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  • 1970-1974  (4,264)
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  • 1
    Electronic Resource
    Electronic Resource
    On different patterns of dendritic bundling in the cerebral cortex of the cat (1974)
    Springer
    Anatomy and embryology 143 (1974), S. 115-126 
    Details
    ISSN: 1432-0568
    Keywords: Cerebral cortex ; Apical dendrites ; Dendritic bundles ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In frontal, horizontal and sagittal paraffin sections through the cat's brain regional differences in the pattern of dendritic bundling have been investigated. It is shown that in the gyrus splenialis and suprasplenialis 2–5 apical dendrites of layer IV pyramids approach each other to form vertical bundles which run straight through layer IV. In the posterior sigmoid gyrus, on the other hand, most apical dendrites arising from the pyramidal cells bifurcate immediately above layer V and give rise to obliquely running branches which cross each other before turning upwards and joining other dendrites to take part in the formation of bundles. In this region the dendritic tree of the pyramidal cells seems to be characterized by an unexpectedly high degree of directional specialization.—In functional terms the findings can be summarized by stating that in the visual and sensorimotor regions of the cat's cerebral cortex basic differences exist in the relation between the apical dendrites of layer V pyramids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00525764
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  • 2
    Electronic Resource
    Electronic Resource
    Zur histogenese und cytogenese des tapetum lucidum cellulosum der katze (1974)
    Springer
    Anatomy and embryology 146 (1974), S. 141-156 
    Details
    ISSN: 1432-0568
    Keywords: Tapetum lucidum cellulosum ; Cat ; Development ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die postnatale Entwicklung des Tapetum lucidum cellulosum der Katze wird mit licht- und elektronenmikroskopischen Methoden untersucht. Bereits am ersten postnatalen Tag sind im Bereich des prospektiven Tapetum zwei Zellarten voneinander zu unterscheiden: 1. mesenchymale Bindegewebszellen und 2. prospektive Tapetumzellen, die durch elektronendichte Tapetumstäbchen gekennzeichnet sind. Die Mesenchymzellen unterteilen als parallel zur Retinaoberfläche ausgebreitete Zellplatten in der Choriodea am hinteren Augenpol den weiten extracellulären Raum in 20–25 etwa 5 μm hohe Schichten. Die Tapetumzellen liegen zwischen den Mesenchymzellplatten und wachsen im Verlaufe der ersten vier postnatalen Wochen innerhalb der Schichten in die Breite, bis sie den extracellulären Raum vollständig ausfüllen und als polygonale Zellen direkt aneinander grenzen. Im weiteren Verlauf der Entwicklung werden die Mesenchymzellplatten rückgebildet, so daß bei der adulten Katze die Tapetumzellschichten direkt übereinander liegen und nur von Netzen elastischer und kollagener Fasern getrennt sind. Die von einer Elementarmembran umgebenen Tapetumstäbchen enthalten einen elektronendichten, in den ersten postnatalen Wochen mit einer Periode von 100 Å quergestreiften Kern. Zunächst nehmen sie an Zahl und Länge zu und füllen am Ende der vierten postnatalen Woche, zu Bündeln von parallel verlaufenden Stäbchen geordnet, das Cytoplasma der Tapetumzellen. Dann nehmen die Tapetumstäbchen an Dicke zu, und ihre Querstreifung wird von einem elektronendichten Material überlagert. Die Entwicklung der Tapetumstäbchen hat eine starke Ähnlichkeit mit der in der Literatur beschriebenen Entwicklung von Melanosomen in Melanocyten. Das Tapetum lucidum cellulosum wird als ein dichter Verband hochdifferenzierter extrakutaner Melanocyten angesehen.
    Notes: Summary The postnatal development of the tapetum lucidum cellulosum of the cat was studied by light and electron microscopy. Already by the first postnatal day two cell types can be distinguished in the prospective tapeta area: 1. mesenchymal cells and 2. prospective tapetal cells, characterized by electron dense, membrane bound, rod-like inclusions. The flattened mesenchymal elements form 20–25 separate layers of cells, which are arranged parallel to the surface of the retina, subdividing the extracellular space of the chorioidea at the posterior pole of the eye into 5 μm high compartments. These compartments contain the tapetal cells which enlarge (in their longitudinal axis) during the first four weeks post partum until they occupy the extracellular space almost completely. At this stage, the tapetal cells are polygonal in shape and closely attached to each other. During the subsequent period of development there is a gradual involution of the mesenchymal cell plates. Thus, in adult cats the individual layers of tapetal cells are only separated from each other by networks of collagen and elastic fibers. The tapetal rods are bound by unit membranes and contain an electron dense core which, during the early postnatal weeks, exhibits a periodic cross-striation (100 Å). The tapetal rods increase in number and length during the first four weeks post partum; by the end of the fourth week, they occupy the whole cytoplasm of the tapetal cells. Parallelly arranged rods are grouped into individual bundles coursing inside the cytoplasm in different directions. Thereafter, the tapetal rods increase in thickness and their cross-striation becomes obscured by an electron dense material. This development of the tapetal rods closely resembles that of melanosomes. Thus the tapetum lucidum cellulosum can be regarded as a compact tissue made up of modified extracutaneous melanocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315591
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  • 3
    Electronic Resource
    Electronic Resource
    Crossed reticulo-reticular projections in the medulla, pons and mesencephalon (1974)
    Springer
    Anatomy and embryology 143 (1974), S. 127-134 
    Details
    ISSN: 1432-0568
    Keywords: Reticular formation ; Crossed connections ; Autoradiography ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Injection of radioactive leucine in various regions of the brain stem reticular formation has revealed the presence of ample crossed reticulo-reticular connections in the cat. The terminal area for the crossed fibers are almost mirror images of the injected sites. The findings made is another example that hitherto unknown fiber connections can be demonstrated by axoplasmic protein tracing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00525765
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  • 4
    Electronic Resource
    Electronic Resource
    Evolution ultrastructurale du labyrinthe de placenta de chatte (1974)
    Springer
    Anatomy and embryology 146 (1974), S. 1-20 
    Details
    ISSN: 1432-0568
    Keywords: Placenta ; Cat ; Differentiation ; Function ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé L'ultrastructure du labyrinthe de placenta de chatte a été étudiée du 45e au 63e jour de gestation. Cette formation endothéliochoriale est composée: d'un endothélium maternel hypertrophié et de cellules géantes déciduales; d'une couche de «substance inerte interstitielle»; du trophoblaste constitué d'une assise syncytiale continue (syncytiotrophoblaste) et d'une assise cellulaire discontinue (cytotrophoblaste); d'un endothélium foetal accompagné de son environnement mésenchymateux. Les capillaires foetaux envahissent progressivement le syncytiotrophoblaste. L'hypertrophie de l'endothélium maternel diminue en fin de gestation; de ce fait la distance, séparant le sang maternel du sang foetal, peut atteindre en certains points 2 μ. L'endothélium maternel, le syncytiotrophoblaste et l'endothélium foetal présentent des signes ultrastructuraux d'un rôle de transfert. La «substance inerte inerte interstitielle», qui sépare les tissus d'origine maternelle des tissus d'origine foetale, est constante mais d'épaisseur variable; elle est spécifique des structures endothéliochoriales. Les cellules géantes déciduales, dont le nombre diminue en fin de gestation comportent parfois un ou plusieurs «corps glycogéniques». Le syncytiotrophoblaste, siége d'activité de biosynthése de stéroïdes, est riche en ergastoplasme, ce qui autorise à postuler la synthése d'hormones protéiques.
    Notes: Summary The ultrastructure of feline placental labyrinth has been studied from the 45th to the 63rd day of gestation. The endotheliochorial structure is composed of: a thick hypertrophied maternal endothelium with giant decidual cells; an “interstitial inert substance”; a continuous syncytial layer (syncytiotrophoblast) and a discontinuous cellular layer (cytotrophoblast) of trophoblast; and a thin foetal endothelium with its surrounding mesenchyme. Foetal capillaries increasingly invade the syncytiotrophoblast. Maternal endothelial hypertrophy is reduced in the last days of gestation. Thus the interval between maternal and foetal bloods may in some areas become 2 μ, in late pregnancy. Foetal endothelium, syncytiotrophoblast, and maternal endothelium demonstrate ultrastructural features of transfer function. The “interstitial inert substance”, which separates maternal from foetal tissue was always evident though with variable thickness. The giant decidual cells which are reduced in late pregnancy, show one or several “glycogen bodies”. The syncytiotrophoblast, where some steroïd biosynthesis has been demonstrated, has an extensive rough endoplasmic reticulum suggestive of protein hormone synthesis activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00341379
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  • 5
    Electronic Resource
    Electronic Resource
    Function and interaction of on and off transients in vision II. Neurophysiology (1974)
    Springer
    Experimental brain research 19 (1974), S. 507-521 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; LGN ; Transients ; Antagonistic inhibition ; Sensory storage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neuronal responses to interruptions of light stimuli were studied in 58 X-type and 7 Y-type LGN relay cells with intra- and extracellular recording techniques. The responses to interruption were then compared with responses to either appearing or disappearing light stimuli which had the same luminance and size as the interrupted stimulus. The extent to which responses to interruption differed from those to appearance and disappearance was studied as a function of the interstimulus interval (ISI), the duration of the stimulus before the interruption (t1) and after the interruption (t2). Responses to stimuli appearing after interruptions of up to 500 msec were weaker than those to appearance and disappearance. This difference decreased with increasing ISI. The difference between responses to appearance and interruption increased as t2 decreased, and decreased as t1 decreased. The reverse was true for the difference between responses to disappearance and interruption. Stimulation of the mesencephalic reticular formation consistently reduced the difference between responses to appearance and disappearance compared with those to interruption for all stimulus conditions. These results are discussed in the context of the psychophysical study presented in the preceding paper. It is shown that the neuronal reactions are reflected in detail by the ability of humans to detect appearances and disappearances that occur during interruptions. EPSP sequences recorded from LGN relay cells and relay cell responses conditioned by reticular stimulation suggest that the differentiation of responses to interruption and change partially occurs already in the retina. This differentiation is subsequently enhanced by antagonistic inhibition in the LGN. It is proposed that these inhibitory interactions at peripheral sites of the visual pathway store visual information and serve to reduce the redundancy of responses to short interruptions of the visual input. Centrifugal modulation of LGN inhibition is proposed to control the trade off between temporal integration and temporal resolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236114
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  • 6
    Electronic Resource
    Electronic Resource
    Neuronal activity during eye movements in a visual association area of cat cerebral cortex (1974)
    Springer
    Experimental brain research 19 (1974), S. 467-477 
    Details
    ISSN: 1432-1106
    Keywords: Suprasylvian gyrus ; Cat ; Single neurons ; Eye movements ; Direction sensitivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 270 single neurons from the anterior part of the middle suprasylvian gyrus (AMSS) were recorded in awake and non-paralyzed cats (Chronic preparation). 10% were unresponsive to visual stimulation, the remainder reacted well to moving visual stimuli. Half of the units tested were directionally selective. Horizontal, or downward preferred directions predominated. Most neurons were relative insensitive to changes of shape, orientation, contrast, and velocity of the visual stimulus. Some neurons preferred rapid (100°/sec) jerky movements, others required complex motions of irregular shapes, a few strongly preferred objects moving towards the animal in the midsagittal plane. 40% of neurons yielded phasic On-Off reaction to flashing stationary spots. Habituation to repeated stimulation was a common feature and occured in 50% of AMSS neurons. In 19% of neurons tested the discharge rate was not affected by saccadic eye movements, when the animal faced a patterned background. Among the remainder two types of saccade associated responses could be distinguished. Type I discharged prior to or simultaneously with the onset of saccades. This early response was usually associated with saccades of particular directions. Saccades in total darkness yielded weaker and less consistent responses. Type II discharged subsequent to the onset of the saccades after a latency of 40 msec (type IIa), 40–80 msec (type IIb) and 80 msec (type IIc). Responses of type IIa are probably consequences of the retinal effects of eye movements. The saccade associated responses of type Ia, IIb and IIc are tentatively interpreted as results of an eye movement-synchroneous subcortical input, which facilitates transmission in AMSS neurons. Presaccadic facilitation, which generates type Ia responses, may be functionally related to shifts of attention prior to eye movements. It is suggested that postsaccadic facilitation, which underlies the reactions of type IIb and IIc, may be a correlate of visual attention during the fixation period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236111
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  • 7
    Electronic Resource
    Electronic Resource
    Reflexes in postganglionic fibres within skin and muscle nerves after noxious stimulation of skin (1974)
    Springer
    Experimental brain research 20 (1974), S. 125-134 
    Details
    ISSN: 1432-1106
    Keywords: Somato-sympathetic reflexes ; Cutaneous and muscle postganglionic neurones ; Noxious stimulation of skin ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Somomato-sympathetic reflexes in postganglionic neurones to skin and muscle induced by noxious stimulation of skin were studied in cats anaesthetized with chloralose. The reflexes were elicited by mechanical damaging stimuli and by temperature stimuli of more than 45°C. 2. In most cutaneous units the spontaneous activity was depressed during noxious stimulation of skin. Some cutaneous units were excited or showed mixed responses. The depression of the spontaneous activity was maximal from the skin area which was innervated by the cutaneous postganglionic neurones and much weaker or not elicitable from other skin areas. 3. Most muscle units were excited during noxious stimulation of skin. This excitation could be elicited from all over the body surface. 4. The effective cutaneous afferent fibres which are involved in these reflexes are the Group III axones which are excitable by mechanical damaging stimuli and the Group IV axones which are excitable by mechanical damaging and/or by thermal noxious stimuli. 5. These investigations reveal that the somato-sympathetic reflexes have opposite organization in cutaneous and muscle postganglionic fibres. The reflex patterns are discussed in relation to a possible central organization of the sympathetic nervous system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234007
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  • 8
    Electronic Resource
    Electronic Resource
    Role of visual experience in the development of optokinetic response in kittens (1974)
    Springer
    Experimental brain research 20 (1974), S. 297-302 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Selective rearing ; Maturation ; OKN ; Perception of motion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Kittens reared in the dark from birth were exposed one hour a day between the 4th and the 10th week of age, to a visual environment which consisted exclusively of vertical edges moving horizontally at a constant speed, and always in the same direction. Total exposure time varied between 10 and 60 hours. 2. At the 12th week of age, optokinetic nystagmus (OKN) in response to displacements of the visual field, was tested. Displacements in the direction that the kittens had experienced during the exposure period elicited immediately an OKN, the frequency of which was related to the speed of the moving pattern. Displacements in the opposite direction elicited a poorer response, only for slowly moving edges. When the speed of the displacement was increased, OKN failed to adapt and finally disappeared. 3. These results suggest the existence, in this type of visuomotor behavior, of a component built up by early visual experience (adaptative component) overlying another component pre-existing visual experience (pre-programmed component).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238319
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  • 9
    Electronic Resource
    Electronic Resource
    Attention in the cat: Electrophysiological and behavioural studies (1974)
    Springer
    Experimental brain research 21 (1974), S. 67-82 
    Details
    ISSN: 1432-1106
    Keywords: Sensory transmission ; Lateral geniculate nucleus ; Visual cortex ; Attentive behaviour ; Vigilance ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The behaviour of 6 cats was studied in a vigilance task. Each cat was trained to press a pedal on the floor of a training box. A waiting interval of fixed (FI) or variable (VI) duration then followed, after which a stimulus (S), a spot of light or a tone, was presented for a short period of time. The cat gave a correct response if, during this time, it pressed a panel. The animal was then rewarded with food. When an experiment had been completed using one S the cat was trained to respond to the other. The latency of response following the onset of S was measured for each waiting interval in the VI schedules. It was found that the longer latencies were associated with the shorter waiting intervals; that is, the cats responded more quickly to S as expectancy increased. Between the time the pedal and pand were pressed the optic tract (OT) was shocked not more than once and the response of the LGN and visual cortex recorded. The time at which the shock was delivered varied from 1 trial to the next. The responsiveness of the LGN and visual cortex did not vary during the waiting interval in either of the FI schedules or in the VI schedule in which S was a spot of light. However, in the VI schedule in which S was a tone, the responsiveness of the visual cortex to the thalamocortical input declined as the length of the waiting interval increased. No changes were observed at the LGN or in the presynaptic cortical response. These results contrast with those observed during changes in the level of arousal as assessed by the ECoG. When the ECoG passed from the synchronised to the desynchronised state there was an increase in the amplitude of the postsynaptic LGN response to the OT shock, but no change in the responsiveness of the cortex to the increased thalamocortical input. These changes in transmission in the visual pathways are discussed in relationship to the animal's behaviour and to the inferred state of attention.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234258
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  • 10
    Electronic Resource
    Electronic Resource
    Electrotonic coupling between motoneurones in the abducens nucleus of the cat (1974)
    Springer
    Experimental brain research 21 (1974), S. 139-154 
    Details
    ISSN: 1432-1106
    Keywords: Electrotonic coupling ; Antidromic responses ; Abducens motoneurone ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The electrical stimulation of the abducens nerve provokes the classical true antidromic invasion of the abducens motoneurone and a depolarization which is often capable of generating full action potentials in the impaled motoneurone. Experiments studying these depolarizations suggest the existence of electrotonic coupling between the abducens motoneurones of the cat. Intracellular activity of the abducens motoneurones was recorded following intracellular stimulation of the impaled neurone and antidromic stimulation of the abducens nerve. Collision between the outgoing action potential and the antidromic volley differentiated the true antidromic spike from the depolarizations which can induce or not action potentials. The latency of the depolarization ranged between 100 and 1200 μsec. Collision demonstrated that the depolarization and the true antidromic action potential have an independent origin. The depolarizations and action potentials which are not conveyed to the motoneurone by its own axon are interpreted to be generated by electrotonic coupling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234386
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  • 11
    Electronic Resource
    Electronic Resource
    Vertical organization in the visual cortex (area 17) in the cat (1974)
    Springer
    Experimental brain research 21 (1974), S. 315-336 
    Details
    ISSN: 1432-1106
    Keywords: Visual cortex (area 17) ; Cat ; Columnar organization ; Retino-cortical scatter ; Intracortical connections
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Responses of cortical cells in the cat's area 17 (central and paracentral area), recorded successively during electrode penetrations perpendicular to the surface, were averaged (PSTH). All cells recorded during one penetration were stimulated with the same stimulus, a slowly moving light or dark slit oriented optimally for the first cell recorded. Comparisons between successively recorded cells were completed by simultaneous recordings from two neurones with the same microelectrode tip. Eye movements as an error were excluded by simultaneous recording of a geniculate cell throughout a cortical penetration. 2. The centers of excitatory receptive fields (ERFs) of simultaneously or successively recorded cells during a penetration may be separated by more than 4°. The mean scatter around a column average is 0.81±0.99° in both directions. The scatter is independent of the recording depth. Whereas the optimal orientation of cells recorded during one penetration was generally similar, the optimal direction (forward and backward movement of an optimally oriented stimulus) was variable. 3. The ERF diameters as determined from the PSTH were between 〈0.5° and 7.5°. During each penetration, cells with small (up to 3.0°) and large (〉3.0°) ERFs could be discriminated. The inhibitory fields (determined with the conditioning method of Bishop, Coombs and Henry, 1971) were between 2.0 and 8.5° along both the optimal and the non-optimal orientation axis of a cell. The borders of inhibitory fields of cells collected during one penetration were also scattered though overlapping. 4. Response analysis of simultaneously and successively recorded cells with different stimuli indicated that, in spite of considerable ERF-overlap, cells with small ERFs had separate excitatory inputs and that intracortical excitatory connections between cells recorded during one penetration were improbable. 5. The ERFs of cells with large ERFs covered a field approximately corresponding to the fields of cells with small ERFs. But a convergent input from many small ERF cells to single large ERF cells was excluded because of the incompatible functional properties of both types of cells, which correspond to some extent to simple and complex cells respectively. 6. It is concluded that cells within cortical cylinders are not connected through excitatory contacts with each other and that most cells in area 17 are excited by individual excitatory geniculate or cortical inputs. Inhibitory connections seem to be the most important intracortical connections. 7. In an Appendix it is shown that anatomical and physiological data do not support significant excitatory convergence of specific geniculate afferents on cortical neurones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235750
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  • 12
    Electronic Resource
    Electronic Resource
    On the origin of the corticotectal projections in the cat (1974)
    Springer
    Experimental brain research 21 (1974), S. 433-439 
    Details
    ISSN: 1432-1106
    Keywords: Superior colliculus ; Visual cortex ; Layer V-pyramids ; Clare Bishop area ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Stereotaxic injection of horseradish peroxidase into the superior colliculus produced retrograde labelling of layer V pyramides in the Clare Bishop area and the lateral bank of the suprasylvian sulcus, in area 17,18 and 19. Single labelled cells were also found scattered in the splenial, the suprasplenial, the lateral and the suprasylvian gyri. In the cruciate sulcus no labelled cells were observed. Autoradiographically, the lateral bank of the suprasylvian sulcus was also shown to give rise to fibres to the superior colliculus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237905
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  • 13
    Electronic Resource
    Electronic Resource
    The lateral reticular nucleus in the cat II. Organization of component activated from bilateral ventral flexor reflex tract (bVFRT) (1974)
    Springer
    Experimental brain research 21 (1974), S. 487-500 
    Details
    ISSN: 1432-1106
    Keywords: Lateral reticular nucleus ; Bilateral ventral flexor reflex tract (bVFRT) ; Spino-reticulo-cerebellar path ; Cerebellum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Neurones in the lateral reticular nucleus (LRN) activated by the bilateral ventral flexor reflex tract (bVFRT-LRN neurones) were identified by their responses to stimulation of fibres descending in the contralateral ventral quadrant of the spinal cord which activate the bVFRT neurones monosynaptically. 2. Eighty-eight of the 134 bVFRT-LRN neurones encountered could be antidromically activated at a low stimulus strength from small areas of the cerebellar surface assumed to represent cortical termination points. 3. The bVFRT-LRN neurones occurred throughout the parvi- and magnocellular parts of the LRN and terminated bilaterally in the anterior lobe and sparsely in the ipsilateral paramedian lobule and in the pyramis. 4. The responses evoked in the bVFRT-LRN neurones on stimulation of the contralateral ventral quadrant at C5 and L1 made it possible to estimate the approximate spinal level from which the bVFRT fibres originated. On this basis the bVFRT-LRN neurones were divided into cervical, thoracic, and lumbar groups receiving bVFRT afferents from mainly one spinal level and a convergence group receiving bVFRT afferents from several levels. 5. The different bVFRT-LRN groups received excitation from different combinations of nerves in the four limbs. 6. The cervical, thoracic and lumbar groups of the bVFRT-LRN neurones occurred in successively more ventrolateral portions of the LRN. 7. The cervical, thoracic and lumbar groups of the bVFRT-LRN neurones terminated in successively more rostral areas of the anterior lobe. 8. The organization of the bVFRT-LRN path is compared with that of the ventral and rostral spinocerebellar tracts. The possible function of the bVFRT-LRN path is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237167
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  • 14
    Electronic Resource
    Electronic Resource
    The projection of the superior colliculus onto the reticular formation of the brain stem an experimental anatomical study in the cat (1974)
    Springer
    Experimental brain research 19 (1974), S. 1-19 
    Details
    ISSN: 1432-1106
    Keywords: Reticular formation ; Superior colliculus ; Cat ; Experimental anatomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Following altogether 18 stereotactically placed lesions of different location and size in the superior colliculus the efferent fibres to the RF and their distribution were traced in silver impregnated, approximately serial sections (Nauta and Fink and Heimer methods), cut in the transverse, horizontal or sagittal plane. The projection to the mesencephalic RF was found to be almost completely ipsilateral, that to the pontomedullary RF largely contralateral. In the mesencephalic RF the fibres end in its dorsal half approximately. In the pons and medulla they supply only the medial 2/3 of the main RF, with two distinct maxima within the total field of termination. One maximum covers the rostral part of the nucleus reticularis gigantocellularis and the adjoining part of the nucleus reticularis pontis caudalis, the other occupies the rostralmost part of the latter and the caudal part of the nucleus reticularis pontis oralis. Of the precerebellar reticular nuclei the contralateral nucleus reticularis tegmenti pontis receives a distinct component of tectal fibres in a small area dorsomedially. Some fibres end in a restricted part of the nucleus reticularis lateralis and in the paramedian reticular nucleus. The tectoreticular projection appears to be organized according to the same principles as other afferents to the RF. In the main RF the areas of termination of the tectoreticular fibres coincide more or less with the areas of termination of corticoreticular, fastigioreticular and vestibuloreticular fibres. These common terminal areas are those which give off the bulk of reticulospinal fibres. Some functional implications of the pattern of organization in the tectoreticular projection are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233392
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  • 15
    Electronic Resource
    Electronic Resource
    Lack of fixed order of recruitment in cat motoneuron pools (1974)
    Springer
    Experimental brain research 20 (1974), S. 101-114 
    Details
    ISSN: 1432-1106
    Keywords: Size principle ; Motoneurons ; Cat ; Recruitment ; Neurophysiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Henneman et al. have shown that a wide variety of stimuli activate motoneurons in the order of their sizes, though some reversals occur. It is not clear which motoneurons should be included in the “pool” from which recruitment by size takes place. The “pool” may consist of 1. all the motoneurons to a given muscle 2. all the motoneurons in a given ventral root or 3. all the motoneurons activated by a given stimulus. We have examined recruitment in the pool of fibers to a given muscle. A variety of mechanical stimuli to cat's legs were used to elicit bursts of activity in gastrocnemius motor units. In 30% of pairs of units, one unit had a consistently lower threshold, i.e. it always began and ended a burst. In the other 70%, either unit could start or end a burst. For 48% of motor unit pairs recorded in either the medial or lateral gastrocnemius, each unit of the pair had runs of firing of at least 10 spikes while the other was totally inactive. By the same criterion, 23% of pairs of temporalis units showed differential activity. During spontaneous breathing there was no consistent recruitment order in 24% of pairs of units in throat respiratory muscles. These data indicate that reversals of recruitment order are relatively common for motoneurons innervating the same muscle. We discuss the possibility that size principle may hold for motoneurons in a single ventral rootlet whose somas are anatomical neighbors (even though they innervate different muscles), but not for motoneurons that are anatomically distant in the cord (even though they innervate the same muscle).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234005
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  • 16
    Electronic Resource
    Electronic Resource
    Effect of differential blocking of motor axons on antidromic activation of Renshaw cells in the cat (1974)
    Springer
    Experimental brain research 20 (1974), S. 135-143 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Renshaw cell ; Antidromic activation ; Differential blocking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Attempts were made to study differences in the relative effectiveness of different size ranges of motor axons to Renshaw cells by differential blocking of larger fibers of the gastrocnemius nerve in cats anesthetized with Nembutal. 1. Differential blocking of larger fibers in the nerve was successfully obtained by applying trapezoid wave current to the nerve. 2. It was shown that more than half (58.1%) of the Renshaw cells receive homogeneous inputs from a motor axon collaterals, 25.8% of the cell receive collateral inputs from a certain group of fibers, and 12.5% of the Renshaw cells were activated by “γ range” fibers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234008
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  • 17
    Electronic Resource
    Electronic Resource
    Reflexes in postganglionic fibres within skin and muscle nerves after mechanical non-noxious stimulation of skin (1974)
    Springer
    Experimental brain research 20 (1974), S. 115-123 
    Details
    ISSN: 1432-1106
    Keywords: Somato-sympathetic reflexes ; Postganglionic fibres to skin and muscle ; Natural stimulation of skin ; Hair-follicle receptors ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Somato-sympathetic reflexes in postganglionic neurones to hairy skin and to muscle produced by mechanical non-noxious stimulation of skin were studied in cats anesthetized with chloralose. Most of the postganglionic fibres investigated were spontaneously active and had presumably vasoconstrictor function. 2. In 60% of the cutaneous postganglionic neurones stimulation of hairs induced predominantly excitation. This excitation was mostly followed by a slight depression of the spontaneous activity. In 30% of the neurones the spontaneous activity was depressed or predominantly depressed by these stimuli. 3. In most muscle postganglionic neurones the spontaneous activity was depressed by stimulation of hairs. 4. In both types of neurones the reflexes were produced by activity in hair follicle receptors with Group II afferents. Hair follicle receptors with Group III afferents most probably also contributed to this effect. Except for a slight depression of the spontaneous activity in some cutaneous postganglionic neurones by slowly adapting receptors, mechanical stimulation of other types of receptors with Group II afferents had no effect on the postganglionic neurones. 5. Reflexes in postganglionic neurones could be elicited by stimulation of hairy skin all over the body surfaces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234006
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  • 18
    Electronic Resource
    Electronic Resource
    Projections thalamiques des noyaux vestibulaires: Etude histologique chez le chat (1974)
    Springer
    Experimental brain research 20 (1974), S. 273-283 
    Details
    ISSN: 1432-1106
    Keywords: Vestibular nuclei ; Thalamic projections ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electrolytic lesions were placed into the left vestibular nuclei of 22 adult cats. Silver impregnation for degenerated terminal fibres of serial sections revealed the existence of a relay of the corticopetal vestibular pathway in the contralateral thalamus. Its main afferent fibres originate in the superior and medial vestibular nuclei. By crosschecking the results it was possible to demarcate a focus of vestibular projections in the ventro-caudal part of the thalamus, situated between the centre median, the ventro-basal group and the caudal segment of the ventro-lateral nucleus. The direct ascending afferents of this focus are relatively few in number. The functional significance of this vestibular relay with regard to the proprioceptive influx passing through this region of the thalamus is open to discussion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238317
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  • 19
    Electronic Resource
    Electronic Resource
    Bilateral semicircular canal inputs to neurons in cat vestibular nuclei (1974)
    Springer
    Experimental brain research 20 (1974), S. 285-296 
    Details
    ISSN: 1432-1106
    Keywords: Ampullary nerve ; Cat ; EPSP ; IPSP ; Vestibular neuron
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The six ampullary nerves in both labyrinths were separately stimulated by electric pulses in anesthetized cats. Resulting responses in neurons in the vestibular nuclei were recorded intracellularly. Almost all the vestibular neurons showed an EPSP in response to stimulation of the ipsilateral ampullary nerve. These neurons were subclassified as A-, L-, and P-neuron receiving specific projections from the anterior, lateral and posterior canal, respectively. Three fourths of the vestibular neurons recorded from received an IPSP in response to stimulation of the contralateral ampullary nerve. Plane-specific contralateral inhibition was found in most of vestibular neurons; i.e. A-, L-, and P-neuron received IPSP from the contralateral posterior, lateral, and anterior ampullary nerve, respectively. Approximately two thirds of vestibular neurons exhibiting the plane-specific inhibition were recorded in the medial vestibular nucleus. A collision test of impulses in primary afferent fibers were performed during recording of ipsilateral EPSPs produced by strong stimulation of more than one ampullary nerve. No positive evidence was provided for the existence of neural convergence on single vestibular neurons from different ampullary nerves on the same side. It is suggested that the plane-specific contralateral inhibition increase the sensitivity of vestibular neurons during head rotation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238318
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  • 20
    Electronic Resource
    Electronic Resource
    Responses of cat vestibular neurons to sinusoidal roll tilt (1974)
    Springer
    Experimental brain research 20 (1974), S. 347-362 
    Details
    ISSN: 1432-1106
    Keywords: Vestibular nuclei ; Tilt response ; Sinusoid ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Extracellular recordings were made in the lateral and inferior vestibular nuclei of decerebrate, unanesthetized cats. The firing patterns of single units were studied using small amplitude sinusoidal roll tilts of from 0.01 Hz to 1.0 Hz. Three-fourths of the tilt-sensitive units showed greater modulation of their firing rates as the frequency of the sinusoidal tilt was increased. The responses of cells in both nuclei were similar. These responses were virtually unchanged in cats with chronically plugged semicircular canals, indicating a probable otolith origin for the dynamics of the tilt response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237380
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  • 21
    Electronic Resource
    Electronic Resource
    Somatosensory cortical involvement in responses to noxious stimulation in the cat (1974)
    Springer
    Experimental brain research 20 (1974), S. 363-374 
    Details
    ISSN: 1432-1106
    Keywords: Pain ; Somatosensation ; Cerebral cortex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The experiment examines the role of the cerebral cortex in regulating responses to noxious stimulation by studying the effects of cortical ablations in cats on escape from electric shock applied to the foot pads. The latency of escape as a function of shock intensity was measured before and after bilateral ablations of various portions of the cat's somatosensory cerebral cortex. Ablations of the second somatosensory cerebral cortex significantly increased the escape response threshold. If the sulci bordering this region were included in the ablation, the threshold increase was greater and longer-lasting. Ablations of the primary somatosensory cortex increased latencies at most intensities of electric shock, but did not change the response thresholds. Ablations of both primary and second somatosensory cortex increased response thresholds and response latencies. None of these ablations altered the responses, however, if the cat had been overtrained for six to seven months prior to surgery. The results suggest that the second somatosensory region and the sulci bordering the second somatosensory region in the cat cerebral cortex are involved in responses to noxious stimulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237381
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  • 22
    Electronic Resource
    Electronic Resource
    An intracellular study of neuronal organization in the visual cortex (1974)
    Springer
    Experimental brain research 21 (1974), S. 45-66 
    Details
    ISSN: 1432-1106
    Keywords: Visual cortex ; Efferent cells ; Non-efferent cells ; Synaptic connection ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neuronal connections in the visual cortex of cat (areas 17 and 18) were studied with intracellular recording and electrical stimulation techniques under Nembutal anaesthesia. Four types of axonal projection were seen; 1. association efferent cells projecting to adjacent cerebral cortex on the ipsilateral side, 2. commissural efferent cells to visual cortex on the contralateral side, 3. corticofugal efferent cells to the ipsilateral lateral geniculate body and superior colliculus, and 4. non-efferent cells whose projection is confined within the visual cortex. Both association and commissural efferent cells were located in layer III, corticofugal efferent cells in layer V and non-efferent cells in layers II–VI. Upon these cells two types of synaptic actions were exerted by the specific visual afferents that originate from the lateral geniculate body; 1. type I, monosynaptic excitation plus disynaptic inhibition and 2. type II, disynaptic excitation plus trisynaptic inhibition. Type I effects were found in layers III–V, and type II in layers II and VI. In the border region between areas 17 and 18 monosynaptic excitation and disynaptic inhibition were produced also by the commissural efferents originating from the contralateral visual cortex. On the basis of these results, a possible neuronal circuitry in the visual cortex is postulated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234257
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  • 23
    Electronic Resource
    Electronic Resource
    The lateral reticular nucleus in the cat I. Mossy fibre distribution in cerebellar cortex (1974)
    Springer
    Experimental brain research 21 (1974), S. 473-486 
    Details
    ISSN: 1432-1106
    Keywords: Lateral reticular nucleus ; Reticulocerebellar projection ; Cerebellum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The areas of the cerebellar cortex receiving fibres from the mLRN (major portion of the lateral reticular nucleus comprising its parvi- and magnocellular parts) were determined by identifying the low-threshold spots on the cerebellar surface from which 286 mLRN neurones could be antidromically activated. 2. The mLRN fibres terminate bilaterally in the anterior lobe and pyramis, and ipsilaterally in the paramedian lobule. Some fibres terminate also in the rostral part of lobule VI but hardly any in other parts of the cortex. It follows that the mLRN projects almost exclusively to the classical spinal receiving areas. 3. Neurones in the parvi- and magnocellular parts project to similar cortical areas. 4. Two regions in the mLRN were distinguished on the basis of their different projection areas. Region A, a dorsolateral portion of the magnocellular part, projects to the ipsilateral parts intermedia of the anterior lobe and the ipsilateral paramedian lobule. Region B, a ventral portion of the parvi- and magnocellular parts, projects bilaterally to the pars intermedia and vermis of the anterior lobe and sparsely to the pyramis. 5. Neurones throughout the parvi- and magnocellular parts receive monosynaptic excitation from fibres ascending in the ventral part of the ipsilateral lateral funiculus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237166
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  • 24
    Electronic Resource
    Electronic Resource
    The lateral reticular nucleus in the cat III. Organization of component activated from ipsilateral forelimb tract (1974)
    Springer
    Experimental brain research 21 (1974), S. 501-513 
    Details
    ISSN: 1432-1106
    Keywords: Lateral reticular nucleus ; Spinoreticular tract ; Cerebellum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The activation of neurones in the mLRN (major portion of lateral reticular nucleus comprising its parvi- and magnocellular parts) by two spinal tracts ascending through the ventral part of the lateral funiculus has been studied by recording from 277 neurones of which 187 could be antidromically activated by stimulation of the cerebellar surface. Forty-eight % of the neurones were activated by the bVFRT and described in a previous paper (Clendenin et al., 1975b) and 12% were activated by a previously unknown tract denoted the ipsilateral forelimb (iF) tract and described in the present paper. 2. The iF-tract is activated by stimulation of nerves in the ipsilateral forelimb only. The response consists of a train of impulses with a high initial frequency and an almost constant latency. Cutaneous afferents and high threshold muscle afferents contribute to the excitation which is mediated by interneurones. 3. The responses to stimulation of peripheral receptors were weak and difficult to classify. 4. The iF-tract activates neurones in the dorsolateral portion of the magnocellular part of the mLRN which projects to the ipsilateral pars intermedia of the anterior lobe and the ipsilateral paramedian lobule. 5. The possible information carried by the iF-tract is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237168
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  • 25
    Electronic Resource
    Electronic Resource
    The organization of projections from the cerebellar nuclei to the contralateral motor cortex in the cat (1974)
    Springer
    Experimental brain research 19 (1974), S. 36-60 
    Details
    ISSN: 1432-1106
    Keywords: Cerebellar nuclei ; Motor cortex ; Evoked potentials ; Topographical organization ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. A topographical study of cerebello-cortical relations was conducted in cats anesthetized with chloralose. The potentials evoked by punctate stimulation of the cerebellar nuclei were recorded at various sites in the contralateral motor cortex. A map of the cortical responses obtained by stimulating each of the cerebellar nuclei was established. For this purpose, the stimulation thresholds as well as the response amplitudes, polarity and latency were noted. 2. Local stimulation of each cerebellar nucleus evoked responses in particular regions of the contralateral motor cortex. When a stimulus was applied to the interpositus nucleus, short latency responses were recorded in the lateral part of the area 4. Dentate nucleus stimulation induced short latency responses in the medial part of area 4 and in area 6. Furthermore, late responses were also recorded laterally in area 4. 3. The interpositus nucleus was found to project to the portion of motor cortical area controlling the distal forelimb with only a fast conducting pathway. The fastigial nucleus seems to be connected with proximal and axial motor areas. The projection system of the dentate nucleus appears to have a temporal organization: a fast conducting pathway was found to project to the axial and proximal motor area while a slower one seems to transmit impulses to the motor area of the forelimb extremity. 4. The functional aspects suggested by the temporal organization of the cerebellocortical inputs and the distribution of each nucleus projections on the motor cortical areas are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233394
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  • 26
    Electronic Resource
    Electronic Resource
    Effets de la stimulation des fibres et des mécanorécepteurs splanchniques sur l'activité unitaire du cortex somesthésique (1974)
    Springer
    Pflügers Archiv 348 (1974), S. 127-137 
    Details
    ISSN: 1432-2013
    Keywords: Splanchnic Afferents ; G.I. and Peritoneal Receptors ; Cortical Projections ; Microelectrode Technique ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The experiments were performed on cats anesthetized with chloralose or Nembutal. The unitary activity of cortical neurons was recorded in the SI and SII areas by means of extracellular glass microelectrodes. The neurons showed frequently a spontaneous discharge (irregular or regular tonic discharge bursts of spikes). The electrical stimulation of contralateral splanchnic nerves produced different effects on a great number of the neurons: 1. early short activation, 2. late activation, 3. early and late complex activation, 4. partial or total inhibition of the spontaneous activity. These effects were obtained in the different cortical layers. Similar results have been observed by mechanical stimulation of the splanchnic receptors located in the gastro-intestinal tract and in the peritoneum. However in this case, the duration and the amplitude of inhibition and activation were generally weaker.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00586475
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  • 27
    Electronic Resource
    Electronic Resource
    Junctions in the central nervous system of the cat (1974)
    Springer
    Cell & tissue research 149 (1974), S. 121-135 
    Details
    ISSN: 1432-0878
    Keywords: Astrocytic membranes ; Cat ; Orthogonal particle-complexes ; Freeze-etching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Fixed and unfixed astrocytic membranes from the CNS of the cat were studied by means of the freeze-etching technique. A variable number of gap junctions was detected in astrocytic membranes. They are characterized by the well known hexagonal composition of their subunits. Besides this type of highly ordered membrane-bound particles, a second one was found. It is composed of four single particles (diameter 5 nm) which form an orthogonal subunit with a side length of about 10 nm. These membrane-associated orthogonal particle complexes (MOPC) could be observed in different stages of aggregation and expansion. They reveal an accumulation in membranes of the marginal glia layers and in the perivascular astrocytic end-feet. Unfixed, glycerol treated membranes, however, do not show these structures. After glycerol treatment of the unfixed membranes by immersion, the MOPC disintegrate to single particles which form clusters of various extension. The clustering phenomenon is dependent on the length of the time of exposure to glycerol. Shortening of the glycerol treatment by intravasal perfusion of the cryoprotectant agent causes an decrease of the clusters. Fragments and transient forms of the MOPC become visible. By variation of different physico-chemical parameters of the washing solution a similar effect on the MOPC was not achieved. The discussion deals with probable functional aspects of the MOPC. They are considered to act as membrane-bound functional multienzyme complexes which a) might play a role in mediating transmembrane passage of metabolites, or b) are essential for CSF control mechanisms, or c) have a functional relation to the nexus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209055
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  • 28
    Electronic Resource
    Electronic Resource
    Some observations on the ultrastructure of the central amygdaloid nucleus in the cat (1974)
    Springer
    Cell & tissue research 151 (1974), S. 489-498 
    Details
    ISSN: 1432-0878
    Keywords: Limbic system ; Cat ; Amygdaloid body ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present study was undertaken to re-examine the central nucleus of the cat in Nissl stained sections, to describe its fine structural characteristics, and to compare the lateral subdivision of this nucleus with the putamen. In Nissl preparations, it was observed that the lateral subdivision of the central nucleus contains a fairly homogeneous population of small cells while the putamen contains both small and large cells. It is the presence of a few large cells at the lateral periphery of the lateral part of the central nucleus that makes the boundary between the two nuclei indistinct. Examination of the fine structure of the medial and lateral subdivisions of the central nucleus revealed the presence of many boutons containing flattened vesicles and fewer with spheroid vesicles. In contrast, most of the boutons in the putamen have spheroid vesicles. It is concluded that the lateral subdivision of the central nucleus may be distinguished from the putamen, except at its most lateral border, by its homogeneous population of small cells and its many boutons containing flattened vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222994
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  • 29
    Electronic Resource
    Electronic Resource
    The mechanical properties of high-density rigid polyurethane foams in compression: II. Yield behavior (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 72-75 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A series of rigid polyurethane foams of densities varying from 65 kg/m-3 to 400 kg/m-3 have been tested in compression as a function of rate and temperature. Two yield points are observed, the lower one being associated with the surface layers, the higher with the bulk of the material. The yield points may be predicted to a first approximation for the higher density foam using a model based on the buckling of a thinwalled cylinder.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140112
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  • 30
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    Electronic Resource
    The influence of crystallinity on the beta-transition in poly(vinyl chloride) (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 362-365 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of changes in crystallinity on the β-transition in poly(vinyl chloride) was studied by dynamic mechanical measurements of loss tangent (tan δ) and storage modulus (E′) over the temperature range -160° to 85°C. Four frequencies were covered, 3.5, 11, 35, and 110 Hz. The data presented demonstrate that crystallinity has a significant influence on the relaxation processes involved in the β-transition. The restrictions on segmental mobility imposed by crystallinity are most pronounced in the region between Tβ and Tg, with Tβ tending to shift to lower temperatures, Tg shifting to slightly higher temperatures, the magnitude of tan δ decreasing, and engineering tensile strength increasing. Our data also show that individual PVC resins have mechanical and physical properties which differ enough so that comparisons which are often made between them may be inconclusive. Moreover, the properties of one resin may be more sensitive to thermal treatment than those of another. We are continuing this study to establish correlations between the observed trends and other important mechanical properties such as impact strength, toughness, tensile, and compressive strength.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140510
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  • 31
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    Electronic Resource
    Stress-strain behavior of polychloroprene vulcanizates containing polymer-gel particles (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 155-158 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The equations of stress-strain of gel-filled polymer under large deformation were derived by using a simple model i.e. a sphere in a cubic matrix. The author finds for no adhesion between the phases: In case of perfect adhesion between the phases: where σ(α) is the stress of a blend at an elongation ratio of α, σR(α) the stress of a rubber matrix at α, σG(αG) the stress of a gel component at αG, σR (αR) the stress of a rubber matrix at αR, φ the volume fraction of gel. The validity of Eq 1 was shown for the polychloroprene vulcanizates containing polystyrene-gel which exhibits no adhesion with the polychloroprene matrix. This result shows the value of the model proposed here. The tensile strength of polychloroprene vulcanizates filled with polychloroprene-gel at break is discussed by the use of Eqs 2-4.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140212
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  • 32
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    Electronic Resource
    Key indicators for plastics performance in consumer products (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 177-188 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Two overriding characteristics for major applications of plastics in consumer products are: - the need for high volume production and - their exposure to hostile environments.Successful application and continued growth for plastics in these products requires knowledgeable prediction of performance in the process to produce the plastic part and in the environments to which it will be exposed during the product's lifetime. Progress on establishing relationships between material properties and structure are described with emphasis on response to melt process conditions and behavior when exposed to hostile environments.Commercial plastics and the processes by which they are converted into useful applications are complex systems. A multitude of interacting variables must be dealt with in order to achieve successful implementation in commercial products. Specific examples are discussed in the area of processing for non-Newtonian flow characteristics and overt effects in injection molding and extrusion, tailoring of polymers within established rheological limits and the influence of melt processing on physical and mechanical properties. The influence of application environments is discussed and specific examples are given for environmental stress cracking, stress-environment embrittlement and the effects of hot water solutions on polymer systems.
    Additional Material: 27 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140305
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  • 33
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    Flow visualization for injection molding of polyethylene and polystyrene melts (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 212-222 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Flow patterns have been observed during the injection molding of rheologically characterized low-density polyethylene and polystyrene melts under various molding conditions. Some studies of high-density polyethylene were also carried out. Various mold designs were included in the study and the flow patterns investigated under both isothermal and cold cavity wall conditions. In addition to investigating injection molding of single polymer melts, flow patterns in the sandwich molding of polyethylene and polystyrene were studied.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140310
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  • 34
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    Time-temperature superpositioning of viscosity-time profiles of three high temperature epoxy resins (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 50-57 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The chemo-rheological behavior has been elucidated for three high temperature epoxy resins. Constant temperature and shear stress measurements were made on a modified Weissenberg Rheogoniometer. Curing behavior of various temperatures is unified by a time-temperature superposition method. The curing rate of one resin, Ferro E-293, is limited by the chemical reaction. The other resins, 3M PR-286 and PR-288, each have consecutively occurring reactions, both of which are diffusion limited. The chemo-rheological information obtained for these materials is used to model viscosity for compression molding of hand-laidup composites.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140109
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    Electronic Resource
    Masthead (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140201
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  • 36
    Electronic Resource
    Electronic Resource
    The measurement of melt flow and melt stability (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 98-100 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The melt flow of a plastic as measured by the standard method (ASTM D-1238) is at a high enough stress so that the flow is non-Newtonian. If the die in the plastometer is replaced by a nonstandard, tapered die of large orifice, a lower stress can be used and the flows are shown to be comparable to Newtonian viscosities measured in a cone and plate rheometer. Under these conditions the plastometer can be used as a sensitive measure of the melt stability of a plastic.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140204
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  • 37
    Electronic Resource
    Electronic Resource
    The surface area of bulk poly(vinyl chloride) (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 120-123 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The porosity of poly (vinyl chloride) (PVC) resin particles produced in bulk polymerization is sensitive to polymerization conditions. Using scanning electron microscopy, 60μ spherical beads of PVC are shown to be composed of loosely packed 1μ spherical subparticles. This complex morphology is characterized by a variability in surface area. The surface area of bulk PVC materials can be measured by a chromatographic technique. The elution time of n-octane as a probe molecule on PVC packed columns is simply related to PVC surface area. At approximately constant particle size (measured by Coulter counter and optical microscopy), surface areas measured by argon adsorption are correlated to chromatographic elution times. The bulk density, plastisol viscosity and pore volume (from mercury penetration porosimetry) are determined and related to specific surface area.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140207
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  • 38
    Electronic Resource
    Electronic Resource
    Cold rolling of polymers 2. Toughness enhancement in amorphous polycarbonates (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 249-259 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of cold rolling on the Izod impact strength of amorphous polycarbonates has been studied. The impact strength is a function of the roll reduction as well as the original sheet thickness. Sheets varying from 0.125 to 0.645 inches in thickness have been studied and roll reductions up to 50 percent have been utilized. It is shown that enhancement in impact strength occurs at very small percent roll reductions. The orientation release stress has been measured as a function of roll reduction and the internal stresses through the thickness of the sheets have been studied by birefringence methods. It is suggested that the residual stresses are responsible for impact enhancement rather than the molecular orientation.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140402
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  • 39
    Electronic Resource
    Electronic Resource
    Characterization of mechanical properties of thermoplastic films by creep measurements (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 702-705 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Plasticized poly(methyl methacrylate) and methyl methacrylate/acrylate copolymer films were examined by isothermal creep at low loads measured at several temperatures from ∼Tg to Tg + 15°C. Viscosity calculated using η = σ/3\documentclass{article}\pagestyle{empty}\begin{document}$ \dot \varepsilon $\end{document} was plotted vs temperature giving precise values for Tg based on a viscosity criterion of η = 1013 poises. Creep fracture data at various temperatures below Tg were interpreted using the maximum apparent viscosity measured at the minima of strain rate vs strain curves. Plots of ηmax VS stress at several temperatures gave values of ΔTg/Δσ of -1° to 2°C/106 N/m2 in agreement with treatment of ΔTg/Δσ based on free volume. Fracture occurred at low elongations when ηmax was ≥1013 poises, and at higher elongations when ηmax was 〈1013 poises supporting the concept that fracture is related to the lowering of Tg under stress. Plots of log σ VS log εb (the elongation at fracture) had the same form as that for crosslinked elastomers above Tg reported by T. L. Smith. Plots of log \documentclass{article}\pagestyle{empty}\begin{document}$ \dot \varepsilon $\end{document}b VS log εb also had the same form supporting proposals on the rate sensitivity of fracture.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141008
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  • 40
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    Electronic Resource
    Variable development response of resists using electron beam lithography: Methods and applications (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 538-541 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In the manufacture of electronic devices for integrated circuits, reducing the number of resist steps is desirable for a variety of reasons. We describe some experiments on a process aimed at reducing the number of resist and registration steps in electron beam lithography. The process involves locally varying the electron dose in an electron sensitive resist (in this case poly[methyl methacrylate]) so that the different levels of exposure can be distinguished by subsequent developing. Reliable results have been achieved with three levels: (i)Strongly exposed (resist removed after short immersion in developer).(ii)Partially exposed or “metastable” (resist removed only after prolonged immersion in developer).(iii)Unexposed.In strongly exposed regions, operations such as etching may take place while using the metastable and unexposed regions to protect the workpiece. Subsequently, the metastable region may be developed for further processing.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140715
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  • 41
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    Electronic Resource
    Linear polycarboranesiloxanes (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 567-572 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Aspects of the present status of structure-property correlations for linear polycarboranesiloxanes which contain rigid carborane cages and flexible siloxane in-chain linkages are discussed. Low temperature secondary transitions, glass transitions, crystallization and melting transitions, and high temperature chemical transformations in inert and air atmospheres are emphasized. The linear polymers serve as the basis for new high-temperature elastomers.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140805
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  • 42
    Electronic Resource
    Electronic Resource
    Thermoforming conditions in transparent/opaque coextruded sheet (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 810-816 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Processors have encountered processing problems in dealing with thermoforming co-extruded sheet where one layer is semitransparent to incident radiant energy of the heater banks and the other is opaque. An analysis of the radiant heating process shows that significant volumetric absorption of radiant energy takes place within the semitransparent sheet. From the model, it is shown that to minimize temperature excursions within laminated sheets (and thus reduce the tendency for delamination and blistering), heater banks should be programmed to cycle in an on-off mode with a rather short cycle period.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141114
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  • 43
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    Electronic Resource
    Effects of a fluid environment on the stiffness of polymers (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 831-839 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effects of an isopropanol environment on the deformation characteristics of copoly (acrylonitrile-butadiene-styrene) (ABS) and poly (vinyl chloride) (PVC) have been investigated. Creep tests were performed in tension and torsion both in air and in isopropanol. It was noted that accelerated rates of creep were encountered during the tensile tests in isopropanol as compared with air but no differences were noted during the torsion tests. An explanation is proposed that the greatly increased creep strains encountered in tension result from diffusion of the fluid into the polymer. The rate of diffusion is controlled by changes in the free volume which occur on application of uniaxial tensile stresses. The existence of the fluid molecules in the polymer matrix reduce its local creep resistance and produce swelling, both of which are manifested as increased creep strains. The fact that no effects were noted during torsion tests (where the free volume remains constant) or when an unstressed specimen was immersed in the fluid indicates that no significant absorption occurs at the equilibrium (unstressed) free volume.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141205
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  • 44
    Electronic Resource
    Electronic Resource
    Prediction of melt elasticity from viscosity data (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 859-867 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A simple method for predicting the primary normal stress function, θ, from viscosity data is proposed. A relation between θ and the viscosity function, θ, based on the Goddard-Miller rheological equation of state, is given. An easy-to-use generalized chart for estimating θ from θ is presented; in order to use this chart, viscosity data must be available from the zero-shear-rate value of the “power law region.” The method was applied to six polymer melts, three polymer solutions, and an aluminum soap solution for which θ had been measured experimentally. Even though θ varied by a factor of 103 over the examined range of shear rate, the theory and experiment seldom differed by more than a factor of 2. The generalized chart for θ was combined with Tanner's theory to prepare a graph which may be used to estimate jet swell from viscosity data. Comparison with experimental data of jet swell for 4 polymer melts shows good agreement.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141209
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  • 45
    Electronic Resource
    Electronic Resource
    Thermodynamics of dissipative materials with entropic elasticity (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 730-733 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polymer solutions and melts can both dissipate mechanical energy in flow, as well as accumulate elastic energy. If the assumption is made that elastic energy can be accumulated only through a decrease of conformational entropy, the general thermodynamic theory for non-linear viscoelastic materials simplifies considerably. In particular, though no generality is lost as far as the constitutive equation for stress is concerned, the energy equation, which allows in principle a calculation of temperature distributions arising from frictional heating and heat removal, reduces to the usual form which is valid for viscous materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141012
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  • 46
    Electronic Resource
    Electronic Resource
    Polymer surface reflectance-absorptance characteristics (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 717-723 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: During an investigation of the time for ignition of polymeric materials under the influence of radiant heating, it was found that the polymer surface reflectance-absorptance characteristics were a major factor in the variance of the ignition times. A subsequent research study was made of the reflectance-absorptance characteristics of those polymers used in the ignition testing. Reflectance values were obtained over the wavelength of 0.3 to 2.5 microns using a double-beam Cary model 14 spectrophotometer with an integrating sphere reflectometer and over the wavelengths of 1.0 to 10.0 microns using a Gier-Dunkle Hohlraum with a Perkin-Elmer spectrophotometer. Absorptance values were obtained by means of Kirchoff's Law,Drawings and graphs are included which illustrate the test apparatus and type of data collected. A table of average absorptances of several polymers are given and listed according to the particular type of heat source used. \documentclass{article}\pagestyle{empty}\begin{document}$$ \alpha _\lambda + r_\lambda = 1 $$\end{document} Average absorptances of the polymers over the monochromatic wavelength span of the heat sources were calculated using the equation \documentclass{article}\pagestyle{empty}\begin{document}$$ \alpha _{{\rm av}} = \frac{{\int_{\lambda _1 }^{\lambda _2 } {\alpha _\lambda e_\lambda d\lambda } }}{{\int_{\lambda _1 }^{\lambda _2 } {e_\lambda {\rm d}\lambda}}} $$\end{document} Mathematical analyses were developed and are presented for both the integrating sphere reflectometer and Gier-Dunkle Hohlraum unit.Drawings and graphs are included which illustrate the test apparatus and type of data collected. A table of average absorptances of several polymers are given and listed according to the particular type of heat source used.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141010
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  • 47
    Electronic Resource
    Electronic Resource
    Heat distortion and mechanical properties of polymers by thermal-mechanical analysis (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 764-767 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polymer properties were measured as a function of temperature at 5 and 10°C per minute heating rates and as a function of time at constant temperature, using the Du Pont 940 thermal-mechanical analyzer. Data are reported on deflection temperature under load, vicat softening temperature, and creep properties. These results have been correlated with ASTM values. These tests require short times and are applicable to thermoplastics, thermosets, and elastomers.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141105
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  • 48
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    Electronic Resource
    The role of crystallite dimensions in mechanical and diffusion characteristics of uniaxially oriented polymers (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 778-781 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Electron microscopy studies indicate that the microfibrils are a well defined element of many uniaxially oriented polymers. On the basis of these results it was inferred that the mechanical responses of uniaxially oriented polymers are similar to those of a parallel ensemble of the microfibrils. An important consequence of this microfibrillar model is that the type of load transfer is independent of crystallite aspect (length/diameter) ratio. The analysis of anisotropy in modulus of uniaxially oriented nylon 6, however, indicates that the load transfer characteristics of these polymers are dependent on crystallite dimension. A series response is observed only with fibers or films of low and intermediate draw ratio. Highly oriented structures, however, exhibit a nearly isotropic response in load transfer. These results show that uniaxial polymers must be analyzed in terms of a model where the crystallites are embedded in an “amorphous” matrix. The equations are derived for modulus, strength, and coefficient of diffusion in terms of crystallite dimensions, and the results compared with the experimental data.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141108
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  • 49
    Electronic Resource
    Electronic Resource
    Masthead (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141201
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  • 50
    Electronic Resource
    Electronic Resource
    The 1974 SPE polyolefin division award address: Phase behavior of polybutene-1 plus polystyrene in carbon tetrachloride (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 827-830 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Ternary phase diagram for several polybutene-1 and polystyrene resins in carbon tetrachloride have been determined. These show: Almost the entire phase diagram is a two-phase region.The composition of each phase is mainly of one polymer type.Increasing the molecular weight of either polymer diminishes compatibility.To our knowledge, this is the first example of phase separation in common solvent polymer solutions that involves a poly α-olefin. Viscosity and surface tension data on the equilibrium phases indicate the phases have the same surface tensions but far different viscosities. The upper phase is mainly polybutene-1 and is much more viscous than the lower phase which is mainly polystyrene. Slight agitation of the phases gives an “emulsion” that may be cast into a polymer film. The film has a continuous phase of Form III polybutene-1 and a dispersed phase of polystyrene. The polystyrene may be extracted from the film by immersion in methyl ethyl ketone to give a porous polybutene-1 film.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141204
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  • 51
    Electronic Resource
    Electronic Resource
    Extruder scale-up by computer (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 853-858 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Computer simulation technology is used to define the problems in scale-up of extruders from 2.5 to 3.5, 4.5, 6.0, and 8.0 inches in diameter. It is shown that the conventional practice of scaling-up channel depths by the square root of the diameter ratio does not take full advantage of the potential output capacity of larger extruders and a faster rate of channel depth increase is proposed. It is also shown that inherent limitations resulting from decreasing barrel surface area and increasing flight clearance with increasing screw diameter will always result in a higher discharge temperature from the larger machine at any practical output rate. Frictional heat generation and heat removal requirements increase with increasing diameter, regardless of the scale-up system used, and these limit the output capability of the larger sizes at low discharge temperatures.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141208
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  • 52
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    Viscosity and shear modulus of PVC-plastisols during gelation and fusion (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 868-872 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The Contraves balance rheometer has been used in a study of the gelation and fusion process of three DOP-based PVC-plastisols and the results compared with those obtained with the Brabender plastograph. The tensile properties of samples fused at different temperatures have also been determined. The rheometer results relate to the temperature dependence of the viscosity, shear modulus, and loss angle of the plastisols used. The viscosity- and modulus-temperature curves are to some extent reminiscent of the torque-temperature curves obtained with the plastograph; the fusion temperatures are slightly different. The loss-angle-temperature curves measured with the rheometer exhibit sharp maxima in the vicinity of the Tg-point of the base polymer. The shear modulus decreases with time when the temperature is kept constant (above the fusion point). This effect is possibly associated with crystallite melting. The temperature necessary to reach the maximum strength plateau of films fused at various temperatures was found to agree (within 10°C) with the maximum in the modulus-temperature curves (minimum in loss-angle-temperature curves) when the rheometer shear rate was sufficiently low. On the whole, the rheometer allows for better temperature control. Also, the fact that the results are given in terms of viscosity and shear modulus may have some advantage in interpreting gelation and fusion data.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141210
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  • 53
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    The electret effect in cellulose acetate reverse osmosis membranes (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 92-97 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The electret potentials developed by reverse osmosis electret membranes help control the undesirable deposition of charged colloidal particles on the membrane surfaces during membrane desalination. These antifouling electret membranes should help prevent the costly flux declines normally associated with deposition of colloidal iron oxides on the reverse osmosis membrane surfaces.Homocharge and heterocharge behavior of cellulose acetate membrane electrets have been studied. Asymmetric reverse osmosis membranes and dense membrane films were studied. The homocharge and heterocharge of cellulose acetate reverse osmosis electret membranes have been explained.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140203
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  • 54
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    Prediction and evaluation of the susceptibilities of glassy thermoplastics to environmental stress cracking (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 167-176 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Glassy, amorphous thermoplastics experience a nearly universal susceptibility to crack and craze formation in the combined presence of stress and a chemical environment. This susceptibility has been evaluated for styrene-acrylonitrile copolymers according to the factors which effect craze initiation and those which limit the rates of flaw propagation. Molecular weight, styrene-acrylonitrile ratio, rubber content, and rubber phase morphology are variables which were found to affect flaw initiation and propagation. Fundamental characterization of the chemical parameters which control the initiation of craze formation in polysulfone and polycarbonate is also presented. In particular, “3-dimensional” solubility parameters have been observed to be a reasonable means of characterizing susceptibility to environmental stress cracking.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140304
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  • 55
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    The weathering degradation of polyolefins (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 206-211 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The mechanism of weathering degradation of polyolefins is discussed. Variations in spectral radiation, temperature, density, polymer absorption spectra, orientation, and sample thickness are related to property deterioration. Organic ultraviolet stabilizers, zinc oxide stabilization, and UV catalyzed degradation are briefly reviewed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140309
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    Masthead (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140401
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  • 57
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    Cold rolling of polymers 3. Properties of rolled crystallized polycarbonates (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 260-263 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Amorphous polycarbonate sheets up to 1/4 inch in thickness have been crystallized both thermally and by acetone vapor sorption. For thick sheets acetone vapor sorption is the superior technique and a method has been developed for assuring homogeneous crystallized sheets. The crystallized polycarbonate can be cold rolled providing there is a residual acetone content to act as a plasticizer for the sheet. The tensile stress strain characteristics of the as-crystallized sheets as well as the rolled crystallized sheets have been determined as a function of the residual acetone content. It is shown that a crystallized polycarbonate whose thickness is reduced by 74 percent can achieve a true stress at fracture of 27,180 psi and a strain of 33 percent. These values are significantly greater than the values obtained for rolled amorphous polycarbonates.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140403
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    Prediction of diallyl phthalate molding performance from laboratory tests II. Comparison of mechanical spectrometer and brabender torque rheometer (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 273-275 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Two series of glass-reinforced diallyl phthalate molding compounds from two different manufacturers were evaluated using a Rheometrics, Inc. Mechanical Spectrometer and a Brabender Torque Rheometer. Comparison of reactivity and minimum viscosity as measured by these two instruments is presented. The Mechanical Spectrometer appears capable of differentiating smaller changes in melt viscosity than does the Brabender Torque Rheometer.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140405
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  • 59
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    Friction and friction-generated temperature at a polymer-metal interface (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 288-291 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Results are presented of friction and thermal tests of molded polyimide and pyrrone polymers. The coefficient of sliding friction up to surface velocities of 2 m/sec (394 ft/min) and the coefficient of thermal expansion from 300 to 500°K (80 to 440°F) were measured. An apparatus was constructed to measure simultaneously the coefficient of sliding friction and the friction-generated temperature. Measurements were made at a nominal pressure-velocity product of 0.25 MN/msec (7100 lb/in.2 × ft/min) and at temperatures between 300 and 500°K (80 and 440°F).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140408
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  • 60
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    Suspension polymerization of vinyl chloride in the presence of propane (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 338-341 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140506
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  • 61
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    Protein structures and protein fibers - a review (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 81-91 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The biochemistry and stereochemistry of proteins are reviewed and related to molecular structure and specifically to the properties governing fiber formation. The conformation of amino acids, polypeptides and proteins are discussed. The amino acid composition of protein is considered in relation to structure, chain length and molecular weight. General descriptions are also given for typical synthetic polypeptides as well as for non-fibrous natural proteins used in fiber manufacture. Mechanisms and modes are presented for fiber formation including a discussion of molecular criteria involving intermolecular cohesive and crystalline configurational forces which are involved in the fiber forming process. These effects are related to treatments and processes, including thermal, mechanical and chemical modifications, which can be applied to protein for the purpose of forming fibers.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140202
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  • 62
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    Dynamic model of a plasticating extruder (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 112-119 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A theoretical model for the simulation of dynamic operation of a plasticating extruder is proposed. The model can be recommended as a tool to study various dynamic situations of interest in the operation of an extruder. Several responses to changes in operating conditions are discussed. They indicate the occurrence of transient maximas and occasional oscillations. The controlling of flow rate by adjusting a valve at the die seems to cause temporary local high peaks in pressure, whereas its control through screw speed seems to be satisfactory.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140206
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  • 63
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    Chemical thickening of low profile polyester resin systems (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 143-146 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Low profile polyesters and sheet molding compounds, SMC, are two of many resin-glass composites that have been commercialized in the past few years. They have evolved through application of earlier technologies and have opened up possibilities for fiber-reinforced plastics. Because of rapid growth, insufficient time has been spent documenting the technical aspects of making SMC. Techniques are thus described that we have used to characterize the rheological properties of the resin mix during its transition from liquid-like (viscous) behavior of the initial formulation through the solid-like (elastic) behavior of the resultant SMC.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140210
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    A rheological study of aqueous separan solutions (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 16-21 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The concentration dependence of the rheological response of aqueous Separan solutions was measured. The shear and primary normal stress response in steady shearing flow, and the relaxation of shear stress following cessation of steady shear flow, were measured with four different polymer solution concentrations. Two different nonlinear constitutive equations, Bird-Carreau and Meister, were used to analyse the data. The Bird-Carreau model fit the steady shear data very well and the parameters obtained from steady shear data allow reasonable estimates of the stress relaxation of these systems. The Meister model provided a fit of the transient stress relaxation data and could be used to estimate the steady shear response. No quantitative molecular theory was developed in this work. However, the nature of the concentration dependence of the Bird-Carreau parameters suggests that as the polymer concentration of aqueous Separan solutions decreases from 2.0 to 0.05 weight percent the solutions should be modeled less by an entangled network theory and more as slightly overlapping hydrodynamic units. The concentration where this behavior seems to be changing appears to be about 0.25 percent by weight of polymer.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140104
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    Masthead (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140301
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  • 66
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    Design of extruder dies using thermoplastics melt properties data (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 298-307 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The procedures developed in this paper enable the die designer to estimate the dimensions of the die at the exit and to define a flow channel within the body of the die appropriate to the required dimensions and output rate of the extruded product. Design procedures are given for predicting die swell (and hence die exit dimensions) from a knowledge of product dimensions, output rate and the basic shear, elasticity, and viscosity data. Within the body of the die the length and included angle of a convergent tapered section should be such that the critical tensile deformation rate is not exceeded. At the die entry the taper angle is related to the tensile and shear viscosities. Analytical expressions based on flow data are given for predicting pressure drops resulting from flow through circular and slot dies of constant cross-section and through conical and wedge-shaped dies. A numerical example shows how the theory may be applied to the design of a die for a thin-walled tube. For the resultant die design, the likely effects are predicted to changes in output rate and melt temperature for the chosen material, of changes in grade of the same type of polymer, and of changes in polymer type.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140410
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    Phenylation of PVC with triphenylaluminum and related model reactions (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 322-331 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: It was theorized that the heat stability of PVC may be improved by exchanging the “weak” (allylic and tertiary) chlorines by groups of higher bond strength, e.g., phenyl. Thus PVC was phenylated by φ3Al in carbon disulfide slurry for various times (1 to 5 hrs) and temperatures (from -30 to +45°C). The φ3Al concentration, temperature and time of φ3Al treatment greatly affect the ultimate heat stability of PVC. Significant improvement in the heat stability was obtained by treating PVC in carbon disulfide at 25°C for 1 hr. The mechanism of phenylation was studied by model experiments in which the possible structural irregularities in PVC were simulated by small molecule chlorine compounds, i.e., 3-chloro-1-butene, 1,3-dichloro-1-butene, 4-choro-2-pentene were models for terminal and inchain allylic chlorines, t-butyl chloride was the model for tertiary chlorine at branch site, and isopropyl chloride simulated regular secondary chlorines. The reactions between φ3Al and these chlorides were carried out at 35°C for various times and the NMR spectra were analyzed. The φ3Al + tBuCl reaction in carbon disulfide gives t-butylbenzene (Wurtz coupling) and isobutylene oligomers. Evidently φ3Al (or the φ2AlCl formed) dehydrochlorinates tBuCl to isobutylene which rapidly oligomerizes in the presence of Lewis acids. In aromatic diluents, i.e., benzene, chlorobenzene, and o-chlorotoluene, Friedel-Crafts t-butylation of the diluent occurs; in mesitylene t-butylation is absent presumably because of steric hindrance and small amounts of t-butylbenzene are formed by Wurtz coupling. All the allyl chlorides examined are rapidly phenylated by φ3Al in carbon disulfide at 35°C and yield the expected products: 3-chloro-1-butene → 1-phenyl-2-butene; 1,3-dichloro-1-butene → 1-chloro-3-phenyl-1-butene; 4-chloro-2-pentene → 4-phenyl-2-pentene. The kinetics of phenylation by φ3Al of model compounds have been studied and the following rate constants were obtained: kallyl = too fast to measure, ktBuCl = 1.0, and kiPrCl = 9 × 10-4 l/mole min. Evidently the rate of the φ3Al + RCl reaction is mainly determined by the stability of the R⊕ intermediate: substituted allylic⊕ ≫ tertiary⊕ ≫ secondary⊕.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140504
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    Polyvinyl chloride insoluble gels: Their structure and effect on properties of cast films (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 352-356 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of insoluble gel material, crystalline aggregates, and suspension particle membranes on the physical and mechanical properties of solution cast films of suspension PVC has been studied. The chemical structure and morphology of the insoluble gel material was also studied. The suspension particle membranes are found to contain significant amounts of hydroxyl and carbonyl groups but are still predominately PVC. These particles affect the transparency of cast films as well as the surface topography by forming discrete clusters upon drying which are uniformly distributed throughout the films. Finally, insoluble gel material is found to have no significant effect on the low and high speed mechanical properties of the films.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140508
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    Processing-morphology-property studies of poly(vinyl chloride) (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 371-381 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Recent morphological studies of plasticized and unplasticified poly(vinyl chloride) (PVC) are reviewed. Suspension polymerized PVC contains particles in a number of different size ranges 100-200Å, 1000-5000Å, 1μ and larger. The larger size particles are broken down during plasticization but both the 100Å and the 1000Å suspension particles retain their identity. The visibility, and presumably, coalescence of these particles is a function of the processing conditions. In particular, the size of the 100Å particle increases with plasticizer content and is most distinct as characterized both by small angle x-ray scattering and electron microscopy for milling temperatures in the 160-170°C. range. Consideration is given to the effect of these particles, their structure, and interrelationship on the rheological properties of the resins.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140512
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    A hysteresis in plasticized poly(vinyl chloride)Taken from theses submitted by S. B. Shah and V. C. Kapasi to Lowell Technological Institute in partial fulfillment of the requirements for the degree of Master of Science in Plastics. (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 386-388 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Plasticized poly(vinyl chloride) formulations were prepared in solid and foam form, and mechanical hysteresis was measured by low-speed tension and compression on an Instron tester and by high-speed rebound on a resiliometer. Hysteresis was greatest in copolymers with vinyl acetate, at low plasticizer concentration, with inefficient plasticizers, at high concentrations of reinforcing fillers, at high expansion to low density, and at high speed of testing. Conversely, resilience was greatest at high plasticizer concentration, with more efficient plasticizers, with non-reinforcing fillers, and at high density.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140514
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    Crystallization of polyethylene oxide under shearThis work supported by a grant from the National Science Foundation. (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 401-412 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A concentric cyclinder dilatometer was designed and built to study the influence of shear on the crystallization kinetics of polymers. This instrument allows crystallization to be followed at both constant temperature and shear rate. Several samples of polyethylene oxide (Carbowax 4000, Carbowax 20-M, and WSR-205) were used. A low molecular weight fraction of the Carbowax 20-M, as well as the unfractionated material, was crystallized under shear. The WSR-205 was studied only in a mixture with Carbowax 4000. It was shown that the kinetics of crystallization of uncrosslinked melts of polyethylene oxide are altered by shear. The induction times for the appearance of crystallinity are shorter in the sheared systems than in the quiescent melts. The Avrami exponents are also higher for crystallization in sheared melts than in quiescent systems and increase with decreasing supercooling. The high values of the Avrami exponent are attributed to the disruption of crystalline aggregates into particles larger than the critical sized nucleus. These particles will persist in the melt and continue to grow spontaneously. A continuous infusion of growing particles into the melt occurs.At constant temperature and shear rate, the induction time of the crystallization curve is influenced by polymer molecular weight. In moderate to high molecular weight samples, the effect of shear becomes saturated at very low shear rates. Decreasing the molecular weight separates the crystallization curves. The curves from the higher shear rates appear at the shorter induction times. However, decreasing the molecular weight below that at the critical entanglement molecular weight allows the nucleation rate, strongly dependent upon the supercooling, to influence the relative positions of the sheared crystallization curves.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140602
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    Analyses for mechanical and electrical properties of epoxy resins used as potting compounds (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 478-480 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Chemical batch-to-batch variations of an acrylonitrile-modified epoxy potting compound were monitored by infrared spectroscopy and correlated to capacitance and hardness measurements of the cured product before and after exposure to high humidity. The reversion resistance of the cured material was dependent upon the amount of a carbonyl functionality in the uncured potting compound. This relationship is an approach to assess the reversion resistance of these types of potting compounds.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140613
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    Stability of polymer composites as positive-temperature-coefficient resistors (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 706-716 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This is a study of materials which are positive-temperature-coefficient resistors. Such materials, composed of conductive particles dispersed in a crystalline polymeric matrix, have been found to be of limited stability. An example is carbon black in high-density polyethylene. On repeated cycling through the anomaly temperature or on extensive heating at or above the anomaly temperature, the room temperature resistivity rises and the anomaly height falls to zero. This phenomenon has been shown to be caused by the absorption of oxygen by the polymer matrix which alters the structure, reduces the crystallinity, and induces an unusual form of crosslinking of a reversible nature.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141009
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    Predicting radiant energy transmission through polymer sheets (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 760-763 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The flux models can be used to accurately predict the transmission or absorption of radiant energy through an absorbing scattering plastic. The apparent absorbing and scattering coefficients are dependent upon the physical characteristics of the body and the incident radiation as well as the actual absorption and scattering coefficients of the material. The apparent interfacial reflectivity can be estimated from the degree of scattering within the material.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141104
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    The significance of capillary rheology testing temperature for predicting PVC extrudability (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 773-777 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A rheological investigation of the saturated fatty acids as lubricants for PVC was made in a Sieglaff-McKelvey rheometer over a wide temperature range. Results reveal that with an increase in carbon chain, fatty acids became more effective in reducing the melt viscosity of PVC. It was also discovered that the maximum viscosity variation due to these materials was observed at 350°F. At test temperatures of 400°F and above, no major viscosity differences were observed. Furthermore, the changes in the melt viscosity were more pronounced at shear rates less than 200 sec-1. The usefulness of the measured viscosity variations at the critical test temperature of 350°F was shown by extrusion. An excellent correlation between the apparent melt viscosity and extrusion melt temperature was found. The criticalness of the test temperature in assessing the effect of lubricants on PVC flow is discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141107
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    Blade-coating of a viscoelastic fluid (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 791-796 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A theory is presented which describes the dynamics of blade-coating of a viscoelstic fluid onto a moving sheet. The method begins with the usual “lubrication” approximation, and develops the solution as a perturbation about the Newtonian case. Viscoelasticity is described by an empirical constitutive equation which shows non-Newtonian viscosity and finite normal stress behavior consistent with typical observations of polymeric fluids. Theoretical results indicate a small increase in coating thickness due to departure from Newtonian behavior, and a significant decrease in the magnitude of the pressure developed under the blade. Consequently, the blade loading can be reduced significantly by viscoelastic effects. The results for the loading may be an artifact of the specific constitutive model, since it can be shown that some viscoelastic fluids, specifically an “elastic Newtonian” fluid, would exhibit increased loading relative to the inelastic Newtonian case.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141110
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  • 77
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    The influence of additives on the flow behavior of ABS (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 806-809 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The flow and processing behavior of commercial plastics is determined not only by the characteristics of the base resin but also by the presence of additives of various kinds. In this study the influence of a number of additives on the rheological behavior of molten ABS was investigated using a capillary extrusion rheometer and a Weissenberg rheogoniometer. The additives studied included molding lubricants, rubber impact modifiers, flame-retardant additives, and residual unreacted components remaining from the polymerization process. The mechanisms by which these species affect flow characteristics are described.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141113
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  • 78
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    Electronic Resource
    A melting model for reciprocating screw injection-molding machines (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 553-559 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A theoretical model for melting in reciprocating screw injection molding machines is proposed. The model permits the calculation of the solid bed profile as a function of time during the injection cycle. It consists of a dynamic extrusion melting model for the rotation period, a transient heat conduction model with a phase transition for the screw rest period, and a proposed model for the drifting of the beginning of melting during the injection cycle.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140803
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  • 79
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    A comparison between simple shear, elongation, and equal biaxial extension deformations (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 573-576 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The rheology of a high molecular weight polyisobutylene “Vistanex” L-80 is measured at 20°C under constant stress creep loading in simple shear and simple elongation and compared with published data for biaxial extension. These data can be reduced to a single curve by the application of simple geometric parameters and instability during extensional flows may be interpreted on the basis of the Considère construction. The results are further extended by dynamic measurements to estimate the viscoelastic response of this material over a time scale of nine orders of magnitude. The rheological response shows an approximately linear relationship with stress up to elongation strains of 1.0, and, because of this, the results do not illuminate the present controversy over the selection of different equations of state to represent non-linear polymer melt flow. However, this body of data, which the authors believe to be the most comprehensive presently available in terms of strain level and deformation geometry, does demonstrate that a viscoelastic polymer can respond to different deformation geometries in a simple manner.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140806
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  • 80
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    Electronic Resource
    Characterization and control of a structural epoxy adhesive (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 597-603 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Problems associated with single-lap shear testing of a structural epoxy adhesive are discussed relative to analyses of the epoxy by infrared spectroscopy, gel permeation chromatography, scanning electron microscopy and other instrumental methods. The value of analytical techniques for assessing the adhesive's cure are shown, including a peculiar correlation of lap shear bond strength with the adhesive's initial uncured state as defined by infrared spectroscopy and gel permeation chromatography. This resulted in the development of definitive batch-to-batch adhesive quality control methods and specifications involving the water content, curing agent, and oxirane concentrations of the uncured system.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140902
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  • 81
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    The mechanical properties of oriented discontinuous fiber-reinforced thermoplastics. I. Unidirectional fiber orientation (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 633-640 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The mechanical properties of a series of thermoplastics reinforced with unidirectionally oriented short fibers are reported. Both organic and inorganic fiber reinforcements were used in fiber volume fractions of 0.10 to 0.50. A number of these composites were found to have excellent strength and stiffness properties combined with good toughness and low density. The dependence of composite properties on the properties of the constituent materials is discussed. Fiber efficiency factors for strength and modulus are presented and models for predicting composite mechanical behavior are reviewed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140908
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  • 82
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    Preface (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 677-677 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: No. Abstract.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141002
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  • 83
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    A step toward molecular-level understanding of the toughness of glassy plastics (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 687-690 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Rigid, glassy plastics differ over a wide range in the amount of energy they can absorb before fracturing under the influence of an applied stress. It is here proposed that molecular structure influences energy absorption more significantly by determining the onset of fracture than by its effect on the energy-dissipating processes themselves. Emphasis has been placed, therefore, on finding a relationship between molecular structure and the onset of fracture. Since many relationships between molecular structure and bulk mechanical response have already been established, it should be a useful step to relate the onset of fracture to bulk mechanical responses. The hypothesis is developed that the appropriate bulk property is the stress-deformation function of the material. The observed stress-deformation function is of such a nature that a highly non-homogeneous deformation is produced at any point of stress concentration. Typically, this is a narrow region in which the material is highly deformed while the deformation in adjacent material is still slight. Fracture initiation is postulated to occur in such a region of high deformation. Differences among polymers in the shape of the stress-deformation function are demonstrated experimentally. These differences correlate with tough-brittle behavior. An explanation is proposed in terms of the probability of fracture initiation.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141005
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  • 84
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    The effect of sudden strain-rate change on the yield behavior of bisphenol-A polycarbonate (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 691-695 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: We wish to investigate the path dependence of yield processes in glassy polymers and to understand this dependence, if any, in terms of molecular mechanisms. To this end the effect of sudden strain-rate change on the yield behavior of bisphenol-A polycarbonate has been investigated. In the experiment, a specimen was initially deformed at a constant elongation rate R1; at an elongation Δlc the rate was suddenly changed to another constant elongation rate R2. R1 was either lower or higher than R2. The yield stress subsequent to the rate change was found to be lower than if the entire deformation was at R1. These results can be satisfactorily explained in terms of Robertson's theory of the yielding of glassy polymers if it is assumed that the “bond flexing” in his theory manifests itself in anelastic deformation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141006
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  • 85
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    Electronic Resource
    Thermal expansion instability and effect on creep of a highly crosslinked polyurethane (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 724-729 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: It was found after heating that the thermal expansion of polyurethane decreased markedly in several hundred hours at constant temperature; after cooling the thermal contraction decreased with time but more slowly. The role of cross-linking as a possible cause of this effect is discussed. Creep during the expanded phase after heating is shown to be much greater than creep after thermal expansion has stabilized at the same temperature. Experiments are described which suggest that the effect of temperature on creep results primarily from thermal expansion rather than from thermal oscillation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141011
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  • 86
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    Electronic Resource
    A study of chain addition polymerization with temperature variations: I. Thermal drift and its effect on polymer properties (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 737-753 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Models of chain addition polymerizations have been analyzed for effects of reaction parameters on thermal behavior during reaction and, consequently, on properties of the polymer formed. Emphasis was placed on the investigation of thermal drift phenomena in particular. Several dimensionless parameters were identified and their role in predicting thermal behavior was established.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141102
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  • 87
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    A design approach to a computer-controlled injection-molding machine (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 768-772 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Plastics injection molding is a complex, multi-variable process which has not yet been clarified. The hardware controller is difficult to build without a realistic mathematical model. One powerful technique for solving such a difficulty is to employ digital control technology which can utilize sophisticated control strategies in order to optimize the system performance. Machine operation and resultant production can be tightly controlled by using computer monitoring, data storage and data logging. This paper presents elements of the various problems that process engineers may encounter in designing a computer-controlled system for plastics injection-molding machinery. The variables of the process and a functional analysis of process control are discussed. A hardware system design; including specification of computer, selection of peripheral devices, system design, and input/output interfacing; is presented.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141106
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  • 88
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    A special mold and tracer technique for studying shear and extensional flows in a mold cavity during injection molding (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 797-800 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A specially-designed mold with interchangeable cavity plates was built and used with an Instron capillary rheometer, type MCR, to investigate the injection molding process. Flow patterns in the mold cavity were illustrated with a visual tracer technique. The complete deformation history of the tracers was recorded on a motion picture for several runs. The flow patterns provide data for computing the components of the rate-of-deformation tensor which is used to identify specific shear and extensional flows. The tracer marks in the cross section of a molding offer information on the skin thickness and the dimensions of the core channel.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141111
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  • 89
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    Nature of fatigue behavior and effect of flaw size in polystyrene (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 801-805 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Fatigue tests under reversed tension-compression have been made on polystyrene specimens in both the unnotched and notched condition. For the notched specimens subject to a stress amplitude of 2500 psi, the log of the fatigue life was found to be a linear function of the log of the notch size. From the data, it was possible to determine an inherent flaw size for polystyrene subject to alternating loading and this value is compared to corresponding values obtained from static tests. Fracture surfaces were examined by scanning electron microscopy and the changes produced by notching are discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141112
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  • 90
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    Electronic Resource
    Molding polycarbonate: Moisture degradation effect on physical and chemical properties (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 817-822 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Proper drying techniques prior to molding can eliminate the overall effects of moisture on the physicochemical properties of polycarbonate. Problems associated with moisture in polycarbonate during molding are described in detail. Moisture absorption is very rapid with the maximum allowable moisture content of 0.03 percent reached within 30 minutes at 49 percent RH and 75°F. Molding with excess moisture content causes a chemical and physical degradation resulting in reduction in tensile impact strength, tensile elongation, ultimate tensile strength, proportional limit and molecular weight. New and existing techniques and procedures for degradation detection were investigated, such as intrinsic viscosity, infrared spectrometry, and thermal methods of analysis. Gel permeation chromatography (GPC) proved the most satisfactory. GPC provided information on the average molecular weight and polydispersity.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141202
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  • 91
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    Segmented polyether ester copolymers - A new generation of high performance thermoplastic elastomersContribution No. 318. (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 848-852 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This paper reviews a series of high-melting thermoplastic polyether esters prepared by transesterification from dimethyl terephthalate, polytetramethylene ether glycol (MW 600-2000), and 1,4-butanediol. The resulting copolyesters exhibit a two-phase domain structure consisting of amorphous polyether ester soft segments and crystalline tetramethylene terephthalate hard segments. By proper selection of the relative amounts of soft and hard segments, polymers ranging from relatively soft elastomers to impact resistant elastoplastics may be obtained. The preparation, polymer structure as well as the physical and environmental properties of polyether esters are discussed. The combination of good melt flow properties, excellent melt stability, and rapid hardening rates permits the processing of these polymers by a wide variety of methods. The excellent processing characteristics in conjunction with the unusual physical and mechanical properties of segmented polyether esters has led to their wide acceptance.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760141207
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  • 92
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    Capillary rheometry of raw elastomers, butadiene-acrylonitrile copolymers (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 137-142 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Capillary rheometry of four butadiene-acrylonitrile copolymer raw elastomers was performed at 125°C over a wide shear rate range. The data were corrected for the effect of pressure on viscosity, for pressure loss in the barrel and at the capillary entrance, for the non-Newtonian velocity profile (Rabinowitsch correction) and for the temperature rise at high shear rates (shear heating). The corrected results were compared to the tensile stress strain data obtained at comparable strain rates. The agreement between the capillary flow data and the tensile stress strain data was quite good, however, some slight systematic differences were noted. The difference was interpreted as the consequence of slipping of materials at the capillary wall. Die swell values were measured and presented as functions of shear rate and capillary length. Extrudate distortions are described.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140209
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  • 93
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    Editorial (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 161-161 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140302
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  • 94
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    The SPE international award address - 1973 the development of impact polystyrene-a review (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 1-11 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The development of impact polystyrene and types of processes used is traced from its inception. Our accidental discovery of the process has resulted in the process being termed unique in that no other commercial polymerization has a like phenomenon that occurs in the shearing agitation step. The prior art and patent picture, before and after the issue of the Dow basic patent, is discussed. The litigation that has centered around the patent is reviewed. Information presented shows that this basic process for impact polystyrene has experienced an unusual degree of commercial success and has led to this family of plastics becoming of major commercial importance. These impact plastics have been accepted and used on a global basis.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140102
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  • 95
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    Free radical formation in oriented polybutadiene during mechanical deformation below Tg (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 22-27 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The tensile behavior of oriented polybutadiene at 83°K is systematically studied as a function of strain rate and pre-test orientation. Electron spin resonance studies of radical formation are made in conjunction with the mechanical tests. Three different modes of mechanical behavior are observed (brittle, crazing and a second ductile behavior without crazing), depending on test conditions. Radical formation is observed in association with the two ductile modes of behavior. The ESR spectra obtained are attributed to a combination of allyl radicals formed by chain scission between the α-methylene groups and peroxy radicals. The relative quantity of the two radical species present is thought to be related to the ratio of cis/trans-isomerism. Stability of the radicals observed with time and with an increase in temperature is studied. Further studies are made of the quantity of environmental test gases absorbed during crazing.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140105
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  • 96
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    Thermoset characterization for moldability analysis (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 231-239 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The injection molding of thermosetting compounds involves complex interactions between material parameters and molding conditions, on one hand, and moldability and the ultimate properties of molded parts, on the other hand. The main role of the molding variables may be related to their effects on the cure time and temperature and on the flow and thermal phenomena that affect orientation and residual stresses. These effects are manifested in the ultimate mechanical properties and shrinkage of the molded articles. Only scattered empirical data are available on the effects of material parameters, like the basic kinetic, thermal, rheological, and pressure-volume-temperature properties of thermosetting compounds. The lack of useful information in this area may be related to the unavailability of sufficient, satisfactory data on the above properties. This situation has also resulted in limitations on meaningful work towards the mathematical modelling of the molding process, which would be useful for the optimization of production rates and product quality. The paper summarizes the status of work in this area with emphasis on recent results relating to kinetic, thermal, and rheological characterization of thermosetting molding compounds.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140312
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  • 97
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    Prediction of diallyl phthalate molding performance from laboratory tests I. Characterization and quality control of diallyl phthalate compounds (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 264-272 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The purpose of this study was two-fold: To determine the relationship between the composition and curing characteristics of glass-reinforced diallyl phthalate (DAP) compounds and their molding performance.To develop quality control tests in order to assure their satisfactory processing.DAP compounds were analyzed with regard to composition, flow, curing characteristics, and heat stability. Tests involving “Spiral of Archimedes” and differential scanning calorimetry (DSC) were used to determine the flow and curing characteristics, respectively. A Brabender torque rheometer was employed to measure both flow and curing properties of DAP. The results obtained indicate that curing properties are of major importance in controlling the DAP processing. Good correlation was observed between the Brabender processing time, the onset curing temperature as measured by DSC, and the molding performance. A computer program was developed capable of calculating the kinetic parameters from the dynamic DSC scan of uncured DAP compounds. The curing data obtained from this method agree with those determined by isothermal DSC. A method based on the penetration of a hot metallic cone has been developed to measure rapidly the percent cure of molded DAP parts. The above mentioned techniques are recommended for the quality control of DAP molding compounds.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140404
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  • 98
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    A sliding scale method for rapid interpretation of rheological measurements (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 292-297 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A simple method has been developed for interpreting rheological data from virtually any of the common rheometers. The method involves the use of an overlapping scale to provide a direct readout of apparent viscosity. The procedure can accommodate data from either rotational or capillary instruments and for the conditions of either shear rate or shear stress control. The method is fully described along with several examples of its application.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140409
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  • 99
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    Electronic Resource
    Structural relationship between thermomechanical history and strength of polymeric solids (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 162-166 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Ultimate properties in polymeric solids strongly depend on thermomechanical history. We have shown that the polymer structure which depends on thermomechanical history can be quantitatively described by the relative amounts of enthalpy and entropy. The excess enthalpy decreases upon annealing and increases under the tensile stress. The increase in excess enthalpy reduces the relaxation time; thus a local brittle-to-ductile transition may be induced by stress concentration. It follows that in a well-annealed material, this transition is more difficult to induce. Effects of molecular weight and orientation are also discussed in terms of dissipation of strain energy as the condition required for the strength of polymeric solids.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140303
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    Electronic Resource
    Electronic Resource
    Structure and properties of flexible vinyl foamsTaken from theses presented to Lowell Technological Institute by Vikram C. Kapasi and Costas N. Georgacopoulos in partial fulfillment of the requirements for the degree of Master of Science in Plastics. (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 193-201 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 28 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140307
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
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