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  • 1985-1989
  • 1965-1969  (763)
  • 1968  (763)
  • Physics  (496)
  • Chemical Engineering  (257)
  • Life Sciences
  • Rat
  • 1
    Electronic Resource
    Electronic Resource
    Zur Resorption freier und konjugierter Gallensäuren im Dünndarm der Ratte in vitro und in vivo (1968)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 261 (1968), S. 314-328 
    Details
    ISSN: 1432-1912
    Keywords: Rat ; Gut ; Absorption ; Free Bile Acids ; Conjugated Bile Acids ; Ratte ; Darm ; Resorption ; freie Gallensäure ; konjugierte Gallensäuren
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Zur Klärung der Frage, ob für die Anreicherung freier Gallensäuren in Coecum und Colon eine unterschiedliche Resorption freier und konjugierter Gallensäuren im Dünndarm mitverantwortlich ist, wurden in vitro an nicht durchbluteten, isoliert durchströmten Dünndarmsegmenten der Ratte ihr Durchtritt und ihre Bindung untersucht. Die Ergebnisse wurden mit denjenigen verglichen, die in vivo an durchbluteten, abgebundenen Ileumschlingen bei Ratten in situ gewonnen wurden. Folgende Gallensäuren standen zur Verfügung: Cholsäure, deren Taurin- und Glycin-Konjugat; Desoxycholsäure sowie deren Taurin- und Glycin-Konjugat. 2. Die in vitro-Versuche ergaben, daß konjugierte Gallensäuren, gemessen an der Konzentration im Resorbat, in größerem Umfange als freie durch die Mucosa treten. Je polarer die Gallensäure, desto größer die Durchtrittsrate. Beim Durchtritt werden weder freie Gallensäuren mit Taurin bzw. Glycin konjugiert, noch werden Gallensäure-Konjugate in nennenswertem Umfange hydrolytisch gespalten. Der durch die Darmwand gebundene Anteil freier Gallensäuren ist größer als der konjugierter. 3. In vivo erfolgt die Resorption aus Ileumschlingen so schnell, daß innerhalb von 15 min von allen Gallensäuren gleichviel resorbiert wird. Das Ausmaß der Bindung der Gallensäuren in der Darmwand ist unterschiedlich. Von Desoxycholsäure wird auch in vivo doppelt soviel gebunden wie von Glykocholsäure. 4. Das Ergebnis der Versuche besagt, daß in vivo eine geringere Resorption für die Anreicherung freier Gallensäuren im Dickdarm keine Rolle spielt. Die Unterschiede im Durchtritt freier und konjugierter Gallensäuren in vitro sind methodisch bedingt.
    Notes: Summary 1. In order to elucidate the question whether the coecal and colonic accumulation of free bile acids is caused by different absorption of free and conjugated bile acids in the small intestine, their penetration and their binding were studied in vitro in isolated rat gut segments. The results were compared with those in vivo obtained with tied loops in situ. The following bile acids were available: cholanic acid, its taurine and glycine conjugates; deoxycholic acid and both its conjugates. 2. The experiments in vitro showed that relative to the concentration in the absorbed fluid, the penetration rate of conjugated bile acids is higher than that of free bile acids. The more polar a bile acid is the greater is the penetration rate. During penetration neither free bile acids are conjugated with taurine or glycine nor conjugated bile acids are hydrolysed. 3. In vivo absorption in ileal loops is so rapid that within 15 min the absorption rate is nearly the same for all bile acids. The amounts of bile acids bound by the tissue vary. In vivo, as in vitro, twice as much deoxycholic acid is bound as glycocholic acid. 4. The results show that in vivo a lesser absorption is of no significance for the accumulation of free bile acids in the colon. The difference in the absorption of free and conjugated bile acids in vitro is caused by the method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00537176
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  • 2
    Electronic Resource
    Electronic Resource
    Aktiver Transport als Komponente der enteralen Phenolrotresorption (1968)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 259 (1968), S. 260-265 
    Details
    ISSN: 1432-1912
    Keywords: Intestine ; Rat ; Phenol red ; Absorption ; Active transport ; Darm ; Ratte ; Phenolrot ; Resorption ; Aktiver Transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Phenolrot wird aus dem Jejunum der Ratte im wesentlichen passiv durch Diffusion resorbiert. Ein kleiner Anteil der resorbierten Menge folgt jedoch Charakteristica eines aktiven Prozesses. Die Resorption dieses Anteils wird durch p-Aminohippursäure (PAH) unterdrückt. In vitro baut Darmgewebe einen Teil von verabreichtem Phenolrot um, so daß es sich dem photometrischen Nachweis entzieht. Diese Reaktion wird durch PAH nicht beeinflußt. Aus dem Verhalten von PAH wird geschlossen, daß es sich bei der aktiven Elimination von Phenolrot aus dem Darm in vivo nicht um Stoffwechsel, sondern um aktiven Transport handelt, der Ähnlichkeit mit den Säuretransportmechanismen in anderen Organen zeigt. Die Phenolrotresorption ist unabhängig von der Art der Kationen in der zur Resorption angebotenen Phenolrotlösung, soweit es sich um Na-, K- oder Na-K-Ionengemische handelt. Auch wenn in der zur Resorption verabreichten Lösung alle Na- und K-Ionen durch Li-Ionen ersetzt werden, bleibt die Phenolrotresorption ohne signifikante Änderung.
    Notes: Summary Phenol red is absorbed from the jejunum of the rat mainly by diffusion. A small proportion of the amount administered, however, disappears from the gut in a way that suggests an active process. The disappearance of this part is inhibited by p-aminohippurate (PAH). In vitro, phenol red is partly metabolized by jejunal tissue. PAH has no effect on this metabolism. From the interaction of PAH it is concluded that the active elimination of phenol red from the jejunum in vivo is due to absorption by active transport and not to metabolism. This process is similar to the active transport of organic acids known in other organs in that it is inhibited by PAH. Absorption of phenol red is not influenced by the kind of cations present in the solution, as far as sodium, potassium or mixtures of both ions are concerned. Substitution of lithium for sodium and potassium does not result in significant changes in the absorption of phenol red.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00536771
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  • 3
    Electronic Resource
    Electronic Resource
    Zur hormonellen Beeinflussung des Hexobarbitalschlafes der Ratte (1968)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 259 (1968), S. 413-418 
    Details
    ISSN: 1432-1912
    Keywords: Cyproterone Acetate ; Hexobarbital Narcosis ; Rat ; Testosterone ; Enzyme Induction ; Cyproteronacetat ; Hexobarbitalnarkose ; Ratte ; Testosteron ; Fermentinduktion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An geschlechtsreifen Ratten wurde der Einfluß des Antiandrogens Cyproteronacetat auf die Hexobarbitalnarkose bei Ratten in Abhängigkeit vom Hormonstatus geprüft. Cyproteronacetat entfaltet in diesem Versuchsmodell nicht seine sonst bekannte spezifische Hemmwirkung gegenüber endogenem und injiziertem Testosteron. Die Vorbehandlung mit Cyproteronacetat führt zu einer Steigerung der mikrosomalen Fermentaktivität in der Leber und damit wahrscheinlich zu einem schnelleren Abbau von Hexobarbital. Die Folge ist eine erhebliche Narkosedauerverkürzung durch diese Verbindung.
    Notes: Summary The influence of the antiandrogen Cyproterone acetate on Hexobarbital narcosis in relation to the hormonal state was investigated in adult rats. In this test model Cyproterone acetate failed to exert its wellknown specific inhibitory action on endogeneous and injected testosterone. Pretreatment with Cyproterone acetate led to enhanced microsomal enzyme activity in the liver and thus probably to a more rapid metabolism of Hexobarbital. The result of this is a significant shortening of the duration of narcosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00538555
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  • 4
    Electronic Resource
    Electronic Resource
    Der Einfluß von Liganden auf die Retention von Eisen nach oraler Verabfolgung an normale und anämische Ratten (1968)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 261 (1968), S. 225-238 
    Details
    ISSN: 1432-1912
    Keywords: Iron Deficiency ; Iron Absorption ; Iron Complexes ; Rat ; Eisenmangel ; Eisen-Resorption ; Eisenkomplexe ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Die Retention von freiem und komplexgebundenem 59Fe-Eisen wurde 6 Tage nach Verabreichung mit der Schlundsonde bei normalen und anämischen Ratten in einer Ganztiermeßanlage bestimmt. 2. Anämische Ratten nahmen fünfmal mehr Eisen auf als normale Tiere, wenn ionisiertes Eisen angeboten wurde. Alle geprüften Komplexbildner vermindern die gesteigerte Eisen-Retention anämischer Ratten. Bezogen auf die Werte der anämischen Gruppe (=100%) wurde die Retention durch EDTA um 87%, durch Citronensäure um 40%, durch Ascorbinsäure um 32% und durch Nicotinhydroxamsäure um 31% herabgesetzt. 3. In Gegenwart von Komplexbildnern ist die Eisen-Retention anämischer Tiere bei Citronensäure 8,7, von EDTA 6,3, von Nicotinhydroxamsäure 3,7 und von Ascorbinsäure 2,7 mal höher als bei normalen.
    Notes: Summary 1. In normal and anemic rats, the retention of free and complex-bound 59Fe-iron was measured with a whole body counter 6 days after its oral administration. 2. If the iron is administered in the ionic form to iron-deficient rats they show a retention of iron 5 times greater than that of normal animals. The increased iron retention of anemic rats is diminished by all complexing agents tested. EDTA reduced it by 87%, citric acid by 40%, ascorbic acid by 32% and nicotine hydroxamic acid by 31%. 3. When the iron is combined with citric acid its retention by iron-deficient rats was 8.7 times increased in comparison to normal rats, with EDTA 6.3 times, with nicotine hydroxamic acid 3.7 and with ascorbic acid 2.7 times.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00536987
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  • 5
    Electronic Resource
    Electronic Resource
    Correlation between noradrenaline content of the brain and the number of granular vesicles in rat hypothalamus during nialamid administration (1968)
    Springer
    Experimental brain research 5 (1968), S. 79-86 
    Details
    ISSN: 1432-1106
    Keywords: Synapse ; Granular vesicles ; Noradrenaline ; Nialamid ; Ventromedial hypothalamic nucleus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structure of ventromedial hypothalamic nucleus was studied in the rat with the electron microscope under circumstances of elevated brain monoamine level following treatment with a monoamine oxidase inhibitor Nialamid. The number of granular vesicles (size in diameter 450–1100 Å) in synaptic terminals increased after Nialamid treatment significantly, while their size did not change; the number of agranular vesicles remained unchanged. The time courses of the increase of granular vesicles and elevation of brain noradrenaline content were approximately parallel. It is inferred that the granular vesicles of size 450 to 1100 Å may possibly be the storage sites of noradrenaline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238698
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of selective hippocampal lesions in the rat on acquisition, performance, and extinction of bar pressing on a fixed ratio schedule (1968)
    Springer
    Experimental brain research 5 (1968), S. 259-266 
    Details
    ISSN: 1432-1106
    Keywords: Hippocampal Lesions ; Rat ; Fixed Ratio ; Acquisition ; Extinction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Rats with bilateral anterior and posterior hippocampal lesions (APH), anterior hippocampal lesions (AH), and controls were trained on CRF for water, and then switched to FR-20. Both hippocampal groups adapted more readily than controls to the FR-20 schedule and maintained significantly higher rates for 45 days. There were no significant differences on FR-20 between the lesion groups. Following FR-20, the rates of all groups were equalized by training on FR-30. During subsequent extinction, the APH group made significantly more responses than both the AH and control groups, while AH and control groups were indistinguishable. The acquisition results were interpreted as indicating increased emotional reactivity to delay of anticipated reward in both hippocampally lesioned groups. The extinction results suggested that APH, but not AH, lesions also result in increased perseveration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235901
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  • 7
    Electronic Resource
    Electronic Resource
    Effects of methylphenidate, pentobarbital, and reserpine on behavior controlled by a schedule of interresponse time reinforcement (1968)
    Springer
    Psychopharmacology 13 (1968), S. 49-64 
    Details
    ISSN: 1432-2072
    Keywords: Operant Behavior ; Methylphenidate ; Pentobarbital ; Reserpine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Three rats, deprived of water, were given separate injections of methylphenidate and pentobarbital after each had received extensive training on a DRL schedule of reinforcement, modified by the inclusion of a limited-hold. Methylphenidate (2.5, 5.0, and 10.0 mg/kg) increased response rates at each of these dosages; pentobarbital increased response rates at dosages of 2.5 mg/kg and 5 mg/kg but had little effect on overall response rate at 10 mg/kg though, at this dose, performance was characterized by periods of rapid responding alternating with periods of inactivity. The rate-increasing effects of the two drugs were found to be qualitatively different. Several mixtures of the two drugs induced rate increases greater than those found when each drug was given separately. However, pentobarbital (10 mg/kg) reduced the rate-increasing effects of methylphenidate obtained when the latter was given alone at a dosage of 10 mg/kg. Chronic pretreatment with reserpine (0.3 mg/kg for 12 days), given to two animals, progressively reduced rate of responding. Methylphenidate antagonized the effects of reserpine as an increasing function of dosage but the resulting pattern of behavior more closely resembled the effects of methylphenidate given alone than performance recorded in the absence of any drug treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00401618
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  • 8
    Electronic Resource
    Electronic Resource
    Die Abhängigkeit der Oberflächenkräfte isolierter Rattenlungen von Atmung, Temperatur und Stoffwechsel (1968)
    Springer
    Pflügers Archiv 304 (1968), S. 315-321 
    Details
    ISSN: 1432-2013
    Keywords: Lung ; Alveolar Surface Tension ; Aerobic Metabolism ; Breathing Mechanics ; Rat ; Lunge ; Alveoläre Oberflächenspannung ; Oxydativer Stoffwechsel ; Atemmechanik ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Beatmet man isolierte Rattenlungen mit Drucken von 0–25 cm H2O (Überbeatmung), so zeigen sich im statischen Druck-Volumen-Diagramm Veränderungen, die auf eine Zunahme der Oberflächenspannung in den Lungenalveolen hinweisen. Läßt man die Lungen im Anschluß an die Beatmung 30 min im geblähten Zustand, so wiest das Verhalten despV-Diagramms auf ein Wiederabsinken der alveolären Oberflächenspannung hin, wenn die Versuche bei 37°C vorgenommen wurden, während eine derartige Änderung bei 20–24°C nur angedeutet nachzuweisen ist. 2. Wird der oxydative stoffwechsel durch Beatmung der Lunge mit N2 oder Vergiftung mit KCN ausgeschaltet, so zeigen sich prinzipiell sowohl während der Beatmung als auch in der Restitutionsphase die gleichen Verhältnisse, nur daß unter anoxischen Bedingungen die alveoläre Oberflächenspannung während der Beatmung noch etwas stärker ansteigt. Danach spielt der oxydative Stoffwechsel für die beobachteten Erscheinungen eine untergeordnete Rolle. 3. Wahrscheinlich wird durch die Überbeatmung der Oberflächenfilm in den Lungenalveolen mechanisch geschädigt, wobei ein Teil des oberflächenaktiven Materials inaktiviert wird. Eine Restitution könnte durch Wiederspreitung des inaktivierten Materials oder durch Übertreten von LAS aus den Alveolarzellen an die Alveolaroberfläche erfolgen.
    Notes: Summary The effect of ventilation on the lung alveolar lining layer has been demonstrated by analysis of pressure-volume diagrams. Ventilation of isolated rat lungs at intrapulmonary pressures of 0–25 cm H2O caused an increase of surface forces in the lungs. After ventilation was stopped the lungs were kept inflated at intrapulmonary pressures of 25 cm H2O up to 60 min. Subsequent analysis of the pressure-volume diagrams indicated a decrease of surface forces at 37°C while at 20–24°C only little recovery occurred. The influence of ventilation with N2 or poisoning with KCN on aerobic cell metabolism was investigated. The increase of surface forces was only slightly more pronounced by anoxia during lung-ventilation than in the above experiments. Aerobic cell metabolism, therefore, did not play an important role in our experiments. It is very likely that the decrease of surface activity following ventilation was caused by mechanical changes of the alveolar lining layer. We believe that, to some extent, the lung alveolar surfactant was inactivated. Recovery can be explained by new spreading of inactivated materials or by passage of lung alveolar surfactant from the alveolar cells to the alveolar surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00587707
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  • 9
    Electronic Resource
    Electronic Resource
    Methoden der Nierenpunktion bei der Ratte (1968)
    Springer
    Clinical and experimental medicine 145 (1968), S. 260-265 
    Details
    ISSN: 1591-9528
    Keywords: Renal puncture ; Renal needle biopsy ; Rat ; Nierenpunktion ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei 90 Ratten wurden insgesamt 266 Nierenpunktionen durchgeführt. Selbst Serienbiopsien (bis zu acht Eingriffen pro Tier bzw. bis fünf Punktionen pro Niere) mit Intervallen von wenigen Tagen wurden gut vertragen. Drei Methoden wurden versucht: percutane Blindbiopsie, Punktion unter Sicht von dorsal (extraperitoneal) bzw. von ventral (transperitoneal). Bei Berücksichtigung der wichtigsten Momente (Ergiebigkeit des Punktates, Schwierigkeit des Eingriffes — auch bei nachfolgenden Punktionen —, lokale Folgen an der Niere und Umgebung) hat sich dastransperitoneale Vorgehen als dieMethode der Wahl erwiesen und ausgezeichnete Ergebnisse geliefert. Die Nierenpunktion der Ratte kann besonders zum Studium des Verlaufes experimenteller Nierenkrankheiten mit morphologischen Methoden empfohlen werden.
    Notes: Summary In 90 rats 266 renal puncture biopsies were performed. Even serial biopsies (up to eight per animal or up to five punctures per kidney, respectively) were tolerated very well. Three methods were attempted: Percutaneous blind biopsy, puncture under direct vision by a dorsal (extraperitoneal) approach and by a ventral (transperitoneal) one. Considering the most important factors (e.g. amount of the puncture sample, difficulty of the procedure even in subsequent punctures, local damage to the kidney) the transperitoneal approach has proved to be the method of choice and excellent results were obtained. Renal puncture of rats are especially suitable for studying diseases of the kidney by morphological methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02044616
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  • 10
    Electronic Resource
    Electronic Resource
    Normale Verteilung51Cr-markierter Lymphocyten in der Ratte und ihre Änderung nach Antilymphocytenserum (1968)
    Springer
    Clinical and experimental medicine 146 (1968), S. 275-283 
    Details
    ISSN: 1591-9528
    Keywords: Anti-lymphocyte serum ; 51Cr-labelled lymphocytes ; Rat ; Antilymphocytenserum ; 51Cr-markierte Lymphocyten ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. 48 Ratten wurden in Äthernarkose 107 51Cr-markierte Lymphocyten suspendiert in Hankscher Lösung und Heparin in die V. femoralis injiziert. Ein Teil der Tiere bekam gleichzeitig Antilymphocytenserum. Dabei wurde festgestellt, daß der normale Abbau51Cr-markierter Lymphocyten in einer bestimmten zeitlichen Reihenfolge in Lunge, Leber, Milz und peripheren Lymphknoten vonstatten geht und51Cr durch die Niere ausgeschieden wird. Ein Wiederansteigen der Radioaktivität in den erwähnten Organen nach 18–22 Tagen wird mit einem Reutilisationseffekt erklärt. 2. Durch Kaninchen-Anti-Ratten-Lymphocytenserum (ALS) wird diese Verteilung beschleunigt und verändert. In der Lunge findet man eine sehr starke, in der Milz dagegen fast gar keine Anhäufung51Cr-markierter Lymphocyten, was auf eine Schädigung dieses Organs durch ALS hinweisen könnte.
    Notes: Summary 1. 107 51Chromium-labelled lymphocytes have been injected into the femoral vein of 48 rats in aetheranaesthesia. The lymphocytes were suspended in heparinized Hank's solution. 20 animals were treated with antilymphocyte serum at the same time. The normal distribution of51Cr-labelled lymphocytes was found to take place in lung, liver, spleen and peripheral lymphnode in a certain chronological order.51Chromium is eliminated by the kidney. After a period of 18–22 days an increase of radioactivity is found in organs mentioned above which is to be explained by reutilisation of radioactivity. 2. This normal distribution is changed by rabbit-anti-rat-lymphocyte serum. In the lung it is found more of51Cr-labelled lymphocytes in the spleen less than in control animals. These findings suggest a damaging effect induced by antilymphocyte serum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02043637
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  • 11
    Electronic Resource
    Electronic Resource
    The influence of microstructural characteristics on the failure properties of a polybutadiene system (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 89-100 
    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 stress-strain characteristic of polymeric binders and solid propellants are dependent on the crosslink density, molecular weight between crosslinks, molecular weight distribution in the binder formulation, volume fraction of filler, and the interaction between the binder and filler particles. This investigation is directed toward elucidation of solid propellant microscopic response and failure mechanisms through characterization of the constitutive effects of crosslink density, molecular weight distribution and curing agent ratio in the binder formulation, and filler fraction. This was accomplished on the ERLA/PBAA propellant system through investigation of three binder formulations with the same curing agent ratio but different crosslink densities; five binder formulations with different curing agent ratios; and four formulations with up to 69.9% by volume of filler.Uniaxial stress-strain characteristics were determined on each formulation at displacement rates of 0.2 to 20.0 in/min at isothermal test conditions ranging from 75 to -90°F. The failure characteristics of a viscoelastic material represent a curve in the three-dimensional space of stress, strain, and time. The ultimate property data on each formulation are presented as projections of this failure curve on the stress-strain, stress-time, and strain-time planes, respectively. Relationships are developed for the dependence of the stress-time, strain-time, and stress-strain failure envelopes on the volume fraction of bound rubber, crosslink density, molecular weight distribution and curing agent ration in the binder component, and the volume fraction of filler.
    Additional Material: 29 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080204
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  • 12
    Electronic Resource
    Electronic Resource
    Plasticizing ethylene copolymers (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 58-63 
    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: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080110
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  • 13
    Electronic Resource
    Electronic Resource
    Deformation of free holes of arbitrary shape in a viscoelastic plate (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 82-88 
    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 independent methods for predicting the deformation of free openings of arbitrary shape in a viscoelastic plate are illustrated.The first method is experimental and is based on the interference of two systems of lines representing the initial and final positions of the material. To demonstrate the moire method, the creep compliance function for polymethylmethacrylate is determined as preliminary information. This function is used as input data in the ensuing theoretical analysis to insure realistic viscoelastic behavior.The second method involves techniques to approximate viscoelastic displacements from known elasticity solutions and known material properties.The methods are applied to two examples: (1) The square hole - to determine the motion of an opening of complicated shape; and (2) an ellipse loaded at 45° - to indicate qualitative agreement with an existing prediction of the motion of cracks in a viscous plate.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080203
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  • 14
    Electronic Resource
    Electronic Resource
    A simple, versatile and inexpensive rheometer for polymer melts (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 116-125 
    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, versatile biconical rehemoter has been developed. This device provides shear creep and creep recovery data for polymer melts over a temperature range of 200-500°F. and a range of applied shear stresses from 2 × 103 to 9 × 105 dynes/cm2.Extensive reheological data have been obtained for two samples each of polyisobutylene and high-density polyethylene. These illustrate the value of the device in obtaining data useful for predicting and understanding the processing properties of polymer melts.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080207
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  • 15
    Electronic Resource
    Electronic Resource
    Masthead (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968) 
    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.760080301
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    Dependence of mechanical properties on molecular motion in polymersTopic of 1968 International Award in Plastics and Science Engineering lecture, New York City, May 8, 1968. (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 161-185 
    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: Considerable progress has been made in the past 20 years in the synthesis, characterization and fabrication of plastics. Previous SPE Award winners, such as Mark, Natta, and Marvel dealt largely with synthesis; Flory with characterization; Alfrey and Du Bois with fabrication. One of the still unsolved problems lies in the realm of relating mechanical properties, such as impact strenght and creep to molecular structure.The design enginner who wishes to use a plastic part is concerned primarily with how some property such as impact strenght varies with temperature, speed of test, test method, etc. The polymer scientist must know why. Through knowing why, he may be able to design better plastics.This paper attempts to survey some of the world-wide progress made in this area in the past 10 years. The ultimate goal is to understand these mechanical properties in terms of internal molecular motions which occur in solid polymers. Internal motion can be detected by electrical, electromagnetic and dynamic mechanical measurements. When these three methods are applied on a given polymer over a range of temperatures, insights can be gained as to the variation of impact strength and other properties with temperature and frequency for that same polymer. These three fundamental methods, which require very small samples (less than 50 grams), can provide insight into the practical behavior of plastic materials over the wide range of temperatures and frequencies encountered in the real world.
    Additional Material: 23 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760080302
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  • 17
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    Prediction of melt viscosity flow curves at various temperatures for some olefin polymers and copolymers (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 235-240 
    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 knowledge of the variation of melt viscosity of thermoplastic polymers with both shear rate and temperature is of considerable importance to plastics engineers as well as to polymer rheologists. The actual measurement of melt viscosity at a large number of temperatures and shear rates is frequently a tedious and time-consuming task. A technique has been developed, based upon the applicability of shear rate-temperature superposition, for predicting the flow curves of a number of olefin polymers and copolymers at various temperatures from experimental data obtained at one temperature for the material in question. The experimental validity for superimposing log shear stress - log shear rate curves at different temperatures along the log shear rate axis has been established for both high and low density polyethylenes, polypropylene, polybutene-1, and poly (ethylene vinyl acetate) copolymers. The temperature dependence of the resultant shift factors has been determined for each system, and the method of utilizing this information to predict viscosities as a function of temperature and shear rate is discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080309
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  • 18
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    Editorial (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 245-245 
    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.760080402
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  • 19
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    Structure-mechanical property relationships in ethylene methacrylic acid copolymers and their salts (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 267-271 
    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 dynamic mechanical study has been made of an ethylenemethacrylic acid copolymer containing 4.1 mole per cent of methacrylic acid units and its sodium, lithium and calcium salts. On the basis of the results and related physical chemical studies it is proposed that the structures of the ionized copolymers consist of three distinct phases - a crystalline polyethylene phase, an amorphous polyethylene phase, and an ionic phase consisting of ionic domains. It is further proposed that the unionized acid copolymer consists of two phases - a crystalline polyethylene phase and an amorphous phase consisting of polyethylene crosslined with hydrogen bonded, carboxylic acid dimers.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080406
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  • 20
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    Effects of high hydrostatic pressure on the mechanical behavior of a crystalline polymer-polyoxymethylene (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 290-301 
    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 true stress-true strain behavior of polyoxymethylene, n(-CH2O), as an example of a bulk semi-crystalline polymer, has been investigated for constant hydrostatic environmental pressures from 1 atmosphere to 8 kilobars with the principal objectives of elucidating the factors controlling flow and fracture. Experiments were conducted in uniaxial tension at room temperature and constant strain rate. The tensile observations were supplemented by measurements of bulk compressibility and stress relaxation behavior at pressure.In contrast with metals and inorganic compounds, the modulus, yield stress and fracture stress of POM increase strongly with pressure by a factor of approximately three at 8 kilobars. The modulus increase is shown from the stress relaxation measurements to be associated with a pressure-induced increase in the β-transition temperature which points to the potential usefulness of the concept of pressure-temperature super-position of mechanical behavior. The characteristics of the pressure dependence of the yield stress demonstrate that yield criteria based on continum mechanics considerations, including the Mohr or Coulomb-Navier criterion, are not valid for general deformation (non-plane strain) conditions in this polymer. The concept of a critical volume change determining the initiation of yielding is suggested to be applicable to semi-crystalline polymers. Comparison with analogous changes in yield stress with temperature points to an increasing contribution to the control of yielding by the initially disordered regions with increasing pressure or decreasing temperature. The fracture behavior observed at pressure eliminates the concepts of a critical stress as a fracture criterion for POM and of a simple reduction in normal stress at points of stress concentration as the principal effect of the applied pressure on fracture.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080409
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  • 21
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    Adhesion of carboxyl-containing polyolefins (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 41-49 
    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: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080108
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  • 22
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    Electronic Resource
    Masthead (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968) 
    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.760080101
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  • 23
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    Abstracts of articles in this issue (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 3-4 
    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.760080102
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  • 24
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    The determination of acrylonitrile-butadiene-styrene terpolymer in polyvinyl chloride compounds using infrared or near-infrared spectrophotometry (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 19-23 
    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: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080105
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  • 25
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    Designing against fracture in brittle plastics (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 130-141 
    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 fracture toughness of a variety of sharply notched tension, bending and rotating disc specimens of PMMA is examined using linear fracture mechanics. It is observed that rapid fracture with a brittle glassy appearance usually follows a period of slow crack growth, denoted by fan shaped markings of local ductility, though still brittle overall. In this near brittle regime the fracture toughness is sensitive to strain rate so that high values of effective surface energy are easily induced by rapid testing or notch bluntness. At impact rates the toughness increases again. For design purposes, in the absence of environmental effects, the onset of slow cracking and rapid (glassy) fracture, can be associated with fracture toughness K1c of about 800 Ibf/in3/2 (90 kg/cm3/2) and 1600 Ibf/in3/2 (180 kg/cm3/2) respectively. Detailed studies have not been made on other materials but a guide to the levels of notch toughness and notch brittle temperatures are given for several plastics.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080209
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  • 26
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    A study of the tensile modulus of short fiber reinforced plastics (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 186-194 
    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: An experimental study of the tensile modulus of unidirectional short fiber reinforced plastics is reported. The data show poor agreement with the theories for the longitudinal case but better agreement in the other cases. A semi-empirical theory is proposed to explain the longitudinal modulus data.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080303
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  • 27
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    Static testing of polyethylene (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 24-31 
    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: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080106
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  • 28
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    Thermal-oxidative behavior of ethylene alkyl acrylate copolymers (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), 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
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080109
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  • 29
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    Spiral and helical fractures (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 227-234 
    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: Spiral and helical fractures can be formed around high-modulus filaments and yarns which are embedded in brittle, amorphous, crosslinked resins. The phenomena are of particular interest because the stress field imposes a highly regular geometry upon the propagating fractures, and because the formation of the large surface area of the spiral fractures provides an efficient mechanism for dissipating strain energy. Development of the approach of the production of discrete geometrical voids with large surface area at predicatable sites may well provide resistance to impact in inherently brittle materials.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080308
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  • 30
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    Laboratory evaluation of the processing characteristics of rigid PVC compounds (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 310-318 
    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 small scale screw extruder designed for laboratory extrusion studies has been developed and its performance characteristics with powder-blended rigid PVC Compounds have been investigated.The use of the extruder in determining the susceptibility of rigid PVC compounds to various die-induced viscoelastic phenomena (fracture, sharkskin, and swell) is described.An investigation of the phenomenon of “nerve” in rigid PVC extrusions has been carried out. It is concluded that nerve is associated with instabilities in the fluxing process occurring in the transition section of the extruder screw design, the operating variables of the process, and the processing characteristics of the compound.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080411
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  • 31
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    The significance of a particle-flow process in PVC melts (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 5-10 
    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: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080103
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  • 32
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    Meaningful testing in the development of new fibers (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 32-40 
    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: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080107
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  • 33
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    Thermogravimetric analysis of vinyl chloride - propylene copolymers and other PVC resins (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 64-73 
    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: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080111
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  • 34
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    Electronic Resource
    Meet the new editor.… (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 81-81 
    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.760080202
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  • 35
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    Comparative swelling behavior of various thermoplastic polymers (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 110-115 
    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 elasticity of polymer melts is of major concern in the processing of plastics. It is usually reflected by dimensional changes. Since the swelling of polymer extrudates depends on the capillary dimensions and the volumetric flow rate, the blow-up must be examined over a range of conditions. Of course, the swelling is also dependent on polymer structure. Consequently, variations in materials and operating conditions necessiate changes in tooling. This paper describes the swelling behavior of several different polymer types and illustrates that viscosity measurements can not be used to predict elasticity.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760080206
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  • 36
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    Correlation of physical and polymer chain properties (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 142-150 
    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: An idealized polymer model is used to examine the magnitude of the catastrophic tensile breaking energy and stress in terms of primary and secondary bonding forces. Computed strengths for primary and secondary bonding are respectively 8000 and 500 times larger than observed values of a common thermoplastic. From other considerations, the glass transition temperature for both elastomeric and thermoplastic polymers is found to show a linear dependence on the cohesive energy per unit length of polymer chain.In special polymer model, the influence of polymer chains on unidirectional elongation is shown to be a function of chain size. Elongation data reported on a series of modified polycarbonates exhibit a correlation with chain size as described by the model. Published data on the polycarbonate series are used to evaluate the correlation between observed deformation breaking energies and cohesive energies calculated from glass transition temperatures.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080210
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  • 37
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    A study of the tensile strength of short fiber reinforced plastics (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 195-201 
    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
    Notes: An experimental study of the tensile strength of unidirectional short fiber reinforced plastics is reported. The data indicate agreement with existing theories as modified to suit plastics. The theory is extrapolated to provide a means for computing the strength of a random composite.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080304
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  • 38
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    Deformation and aging of quenched polypropylene (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 210-215 
    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 physical properties, i. e., yield stress and stress-strain curve of the quenched (“smectic”) form of polypropylene have been shown to be time dependent at room temperature. The yield stress increases linearly with the logarithm of film age. No changes in the x-ray diffraction pattern, infra-red spectrum, electron diffraction pattern or morphology have been observed corresponding to this change in physical properties. A molecular mechanism is proposed which will explain this again process. Spherulites of the quenched form have been found to deform affinely when drawn. In contrast to this, slow cooled films show complete destruction of internal spherulite (lamellar) order, indicating a complex mechanism of deformation.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760080306
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  • 39
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    Properties of block versus random copolymers (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 216-226 
    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: Physical and mechanical properties of block copolymers are compared and correlated with the corresponding random copolymers. The important properties of melting point, transition temperatures, tensile strength, modulus, and elastic properties depend upon the structural arrangement of the molecular units comprising the polymer strecture. All available data suggest overwhelmingly that properties of block copolymers are superior to those of random copolymers. A block copolymer can have properties characteristic of each of the homopolymers from which it is derived as well as a set of properties due to the polymer strcture as a whole. Block copolymers have an advantage over random copolymers in that a crystalline polymer can be modified without significant reduction of its melting point, modulus, tensile strength, and elastic properties, and by suitable selection of a second component it affords a means of “building in” a particular property.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760080307
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  • 40
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    Stress-strain behavior of the craze (1968)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 8 (1968), S. 281-289 
    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 constitution and properties of crazes in glassy polymers and their relation to crack propagation are reviewed. New evidence is discussed which shows the craze to be much softer than the parent polymer but capable of sustaining large stresses and strains up to the point of failure. Craze failure is much more dependent on polymer molecular weight than is craze formation, and this difference is reflected in changes in both fracture surface morphology and crack toughness with molecular weight. Finally craze mechanical properties are thought to be integrally related to the mechanical behavior of high impact plastics.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760080408
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  • 41
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    Optical studies of the stress-induced crystallization of rubber (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1-30 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The low-angle light scattering by films of stretched natural and synthetic rubbers was investigated. Intense Vv scattering is found under conditions when crystallization occurs which is characteristic of the scattering from aggregates of dimensions comparable with the wavelength of visible light. These were identified with the γ fibrils described by Andrews. The dependence of scattering was studied as a function of light polarization direction, orientation direction, elongation, temperature, degree of swelling, type of swelling liquid, and degree of crosslinking. It was concluded that the scattering unit consists of an assembly of crystals with their chain axes parallel to the stretching direction, but (in the case of natural rubber at high elongations) with the fibril axis at a slight angle to the stretching direction. The scattering is not affected much by swelling but is decreased upon increasing the temperature. Upon recooling the scattering returns, but does so over several hours, indicating that much of the scattering arises from secondary crystallization.
    Additional Material: 23 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060101
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    Molecular weights and molecular weight distribution of polymers by equilibrium ultracentrifugation. Part II. Molecular weight distribution (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 111-127 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A method has been developed for determining the molecular weight distribution of a polymer sample from the sedimentation-diffusion equilibrium data for a solution under pseudo-ideal conditions. From some theoretical examples it appears that the method works well and that the molecular weight distribution can be determined with a reasonable degree of resolution. From three polymer samples (polyethylene, polystyrene, and polycaprolactam) the molecular weight distribution was determined in this way. The average molecular weights, M̄n, M̄w, M̄z, and Mz+1, calculated from these distribution functions agree well with those calculated directly from the equilibrium data.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060105
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  • 43
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    Flow birefringence and polydispersityPresented in part at the International Symposium on Macromolecular Chemistry, Prague, 1965. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 141-154 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Flow birefringence data for dilute solutions of various linear and branched polymers of different degrees of polydispersity are discussed. The polymers considered are polystyrene, polypropylene, and polyethylene. By making use of a well-known stress-optical relation, reduced elastic normal stresses, which can also be interpreted as coil expansions, are plotted against reduced shear stresses. As elastic normal stresses are rather sensitive to the shape of the molecular weight distribution at high molecular weight, a characteristic, p, related to the skewness of the distribution, is obtained. Experimental values of p are compared with theoretical ones based on special types of distribution functions. Attention is paid to the method of extrapolating experimental results to zero shear stress and concentration.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060107
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    Determination of orientation of the crystalline and amorphous phases in polyethylene by X-ray diffraction (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 281-288 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: For polyethylene fibers, orientation parameters of the form 〈cos2 φ〉 were calculated from traces obtained with an x-ray diffractometer equipped with an orientation integrator. The angle φ is that which a crystal or molecular axis makes with the fiber axis. Traces over a continuous range of diffraction angle were obtained for (2/π)Iav, and also the weighted averages (2/π)Iav 〈cos2φ〉 and (2/π)Iav 〈sin2φ〉, where Iav is the intensity averaged over all orientations. The orientation for the crystal a, b, and c axes were determined from area measurements of the {110} and {200} lines, and the orientation parameter for the molecular axis in the amorphous phase was determined from area measurements of the amorphous halos. An undrawn fiber showed a slight a and c axis orientation along the fiber axis, and a slight transverse orientation of the b axis and the molecular axis. For a highly drawn fiber the orientation parameter for the c axis was 0.98 and for the molecular axis 0.65. The degree of crystallinity, measured from the (2/π)Iav versus 2θ traces, were 66.1% and 73.3% for the undrawn and drawn fiber, respectively.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060118
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  • 45
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    Stress-strain behavior of elastic materials. O. H. Varga. Interscience, New York, 1966. 190 pp. $11.00 (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 301-301 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060121
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  • 46
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    Polymer fractionation. II. The analytical problem (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 383-406 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Complete fractionations into 5, 10, and 20 fractions were calculated by a numerical method based on the Flory-Huggins theory in order to evaluate various procedures for determining the molecular weight distribution from fractionation data. If the initial distributions are wide, the differential distribution cannot be accurately reconstructed, not even if each fraction is characterized by two average molecular weights (instead of one, as is customary). In addition to this inadequacy in the evaluation procedure there are the experimental errors which further detract from the accuracy of the result. The integral distribution can, in some cases, be approximated fairly well by means of the Schulz method, provided that the polymer is separated into many fractions with narrow distributions. However, the integral distribution thus obtained does not reflect details in the differential distribution. Polymer fractionation does not appear to be a suitable procedure for accurate determination of the differential distribution. From the assembled material, a thermodynamic method has been derived which seems to hold out better prospects. It should enable the differential distribution to be directly determined from a detailed analysis of the liquid-liquid phase relationships, provided the free energy of mixing function of the system is known.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060205
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  • 47
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    On the possibility of chain folding in solutions of normal paraffins and polyethylene (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 451-456 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A simple statistical thermodynamic argument is presented in which the probability of intramolecular chain folding of normal paraffins and polyethylene in solution is examined. This possibility is based on the existence of low-energy intramolecular conformations which are stable enough to overcome the tendency of a chain molecule to assume a random arrangement in solution. Some rough estimates of the magnitudes of energetic interaction in straight-chain hydrocarbons are made to demonstrate the plausibility of this hypothesis. The experimental support for this model arises from NMR spectra of normal paraffins in aromatic hydrocarbon solvents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060302
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  • 48
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    Electronic and ionic conductivity in nylon 66Presented in part at the 152md American Chemical Society Meeting, New York City, September 1966. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 463-477 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The conductivity of dry poly(hexamethylene adipamide) (nylon 66) was measured as a function of time and temperature. Three temperature ranges were observed in which the time dependence of conductivity differed: (a) below 80°C. the conductivity decreased continuously with time; (b) between 80°C. and 110°C. the conductivity remained constant over long periods; (c) above 120°C. a continuous decrease in conductivity was again observed. In other experiments the volume of gas evolved from the nylon film was measured under continuous potential and compared with the total current passed through the sample. It was observed that above 120°C. the gas evolved corresponded to about one-half the volume calculated if the conduction process involved only protons. Below 120°C. the gas evolved corresponded to an increasingly small fraction of the total current until below 90°C. no evolution of gas was observed. This suggests that at temperatures above 120°C. conduction involves the transport of both protons and electrons, whereas at lower temperatures it is electronic. Mechanisms of conduction are discussed.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060304
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  • 49
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    Identification of a stereoblock poly(methyl methacrylate) sample with a stereocomplex (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 509-516 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Acid hydrolysis of a stereoblock poly(methyl methacrylate) sample leads to a mixture of isotactic and syndiotactic poly(methacrylic acid) which can be separated by electrophoresis. The experiment confirms the stereochemical identity between the so-called “stereoblock” poly(methyl methacrylate) and the stereocomplex which syndiotactic and isotactic poly(methyl methacrylate) form in the ratio 2:1. A possible mechanism of replica polymerization is suggested to account for this effect.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060308
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  • 50
    Electronic Resource
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    Conformation and normal frequency distribution of polymer chains (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 529-558 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It is argued on the basis of a simple model for a polymer chain that characteristics of conformation can be determined from the analysis of the frequency distribution of backbone vibrations. In a chain with one degree of freedom per repeat unit, a fold tends to uncouple the motions on each side of the fold. This transfers highest and lowest modes towards the mean value. Conversely, a local unfolding of a random chain enhances the coupling and produces out-of-band modes. From the ordering of these modes, statistical aftereffects can be detected. The Green's function method allows a calculation of the single localized mode as a function of angular parameters. The dynamical matrix elements of the Kirkwood-Pitzer model are calculated for a folded polyethylene backbone chain. The eigenvalue distribution is determined with the Givens-Sturm procedure. It indicates a one-to-one correspondence between modes in the vicinity of 670 cm.-1 in the stretch-bend gap and chain folds, for low concentration of folds. We conclude that conformations should have two characteristic parameters distinctively reflected in the frequency distribution, namely the range of allowed dihedral angles and the ordering of configurations along the chain. The frequency distribution for a given conformation depends however on the force constant ratios when the degree of freedom is greater than one. Interpretation of the frequency spectrum is then made by adjustment of dynamical and geometrical parameters. These are seen to be dependent variables with respect to the spectrum.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060310
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    Electronic Resource
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    Load drop at the upper yield point of a polymer (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 607-620 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The stress-system curves have been measured for isotropic and oriented specimens of poly(ethylene terephthalate) in extension, shear, and compression. It was found that for all these types of deformations there was an intrinsic yield drop, i.e., a fall in true stress. It is concluded therefore that the stress for initiation is greater than the stress for propagation of yielding.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060314
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    Distribution of tensile data of vulcanized rubbers. I. Tensile data of SBR vulcanizates loaded with light calcium carbonate (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 639-651 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: When the first asymptotic probability function of smallest values was applied to analyze the distribution of tensile strength data for rubbers, good agreement between observed values and theory did not always result. In order to improve the agreement, use of another distribution function, the third asymptotic probability function, was proposed. Experiments verified that this function yielded good agreement with theory for the distribution of tensile strengths of rubbers, especially for SBR vulcanizates loaded with light calcium carbonate. The third asymptotic probability function contains three parameters: the characteristic value V, the lower limit ε, and the shape parameter k which is dimensionless. Analysis is made by use of a logarithmic extremal probability paper on which the probability function plots as a straight line if ε = 0. There appears to be a lower limit for the distribution of tensile strengths but not for the distribution of elongations. This suggests that the tensile properties follow the third asymptotic distribution function, with the breaking elongations following the simplified form of the Weibull distribution.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060316
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    Diffusion in atactic polystyrene above the glass transition point (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 675-685 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Diffusivities and solubilities in the system n-pentane-polystyrene were measured for low penetrant concentrations at several temperatures above the glass transition temperature. The relatively sharp changes in the activation energy of diffusion and the heat of solution near 150°C. are interpreted tentatively as indicating that a second-order transition exists in atactic polystyrene above the glass transition temperature. Evidence indicating the existence of this transition has been obtained by other techniques and the effects observed in this study should also be present in the diffusion of other penetrants in polystyrene. Correlation of these and other available data for diffusion in polystyrene as a function of the molecular size of the penetrant indicates that specific thermodynamic interactions between polymer and penetrant have little influence on the diffusion process.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060403
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    Temperature dependence of the bulk crystallization rate of polymers (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 695-706 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Data already existing in the literature for the overall crystallization kinetics of a variety of polymers have been analyzed according to different possible nucleation mechanisms. The conclusions reached are similar to those previously deduced from an examination of ata for spherulite growth rates. It is demonstrated that, if allowed a reasonable choice for the equilibrium melting temperature, no unbiased selection of a unique nucleation process can be made. Moreover, a set of universal parameters exists for each of the nucleation and growth processes considered which allows the data for all polymers to be represented by a single straight line. The only quantities that are unique to a given polymer are the equilibriun melting temperature and the activation energy for transport.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060405
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  • 55
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    Solution properties of poly(methyl acrylate) and (1:1) poly(styrene-co-methyl acrylate) (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 713-721 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(methyl acrylate) (PMA) and 1:1 poly(styrene-co-methyl acrylate) (PSMA) were prepared by solution and bulk polymerization, respectively. The copolymer was analyzed with NMR to ascertain its composition and microstructure. The solution properties of unfractionated PMA and fractionated PSMA in ethyl acetate were investigated by light-scattering and viscosity techniques at 35°C. Narrow composition heterogeneity as revealed from the light-scattering measurements in different solvents justified the use of a single solvent for the copolymer characterization. The equations relating the limiting viscosity number to molecular weight, the molecular dimension to molecular weight, etc., were found for homopolymer and copolymers in ethyl acetate at 35°C. In the evaluation of the Flory constant K for the unperturbed state by methods based on Flory-Fox-Schaefgen, Kurata-Stockmayer, and Stockmayer-Fixman expressions, only the first method gave a value for PMA in ethyl acetate, consistent with that obtained in other solvents, whereas similar values of K were obtained by the three methods for PSMA in ethyl acetate. The studies indicate reduced thermodynamic interaction for PSMA-ethyl acetate compared to PMA-ethyl acetate, but increased steric effect in the copolymer compared with the homopolymer.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060407
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    Multiple-order light scattering from ringed spherulites (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 783-786 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Light scattering from polymer films containing ringed spherulites may show multiple-order intensity maxima directly related to the period of the banded structure. Calculations based on spherulite models where the angle of twist of lamellae ω varies linearly with radial distance predict only first-order peaks. If the variation of ω is nonlinear, even though the ring spacing remains constant, higher-order intensity maxima will result. Other sources of multiple-order scattering are considered. It is concluded that for polyethylene the presence of multiple-order scattering is due to non-uniform twisting of the lamellae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060412
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  • 57
    Electronic Resource
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    Influence of crystallinity and orientation on sonic velocity and birefringence in poly(ethylene terephthalate) fibers (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 795-800 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060414
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  • 58
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    Crosslinked oligoethylene glycols: Correlation between their structure and some rheological properties (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 801-811 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Six oligoethylene glycols were crosslinked with triphenylmethane triisocyanate, and polymers with systematically changing network chain lengths were obtained and investigated. The 10-sec. torsion moduli versus temperature, glass transition temperatures, and cohesive energy densities of the polymers were determined and studied. The 10-sec. torsion modulus versus temperature plots show that all six polymers have a glassy transition and rubbery region of rheological behavior. The front factor calculated from the equation for the torsion modulus in the rubbery region when measured values of the modulus were used was compared with the front factor computed from equations that take into consideration molecular structures of the rubbery networks. With the exception of the case of crosslinked diethylene glycol the agreement in all the other cases between the values obtained for the front factor in both ways was good. In the investigated range of temperatures the polymers have below the glass transition temperature another transition point. The solubility parameters of the polymers, calculated from swelling experiments, were with the exception of the first member in the series almost identical.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060501
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    Infrared spectrum of poly(vinylidene fluoride) (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 861-869 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two crystalline forms (α and β) of poly(vinylidene fluoride) were studied by infrared spectroscopy. The spectral differences permitted the study of the transformation and the ratio of the two forms. The ordinary \documentclass{article}\pagestyle{empty}\begin{document}$ \vec G,\vec F $\end{document} matrix method was used to calculate the fundamental mode with a Urey-Bradley type potential field, and a preferred set of the force constants was obtained.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060506
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    Electronic Resource
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    Nuclear magnetic resonance study of drawn poly(ethylene glycol) (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 653-656 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060317
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  • 61
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    Isochronal temperature-concentration diagram for a polymer-diluent system (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 687-694 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The results of an investigation of the viscoelastic and thermal properties of the gelatin-glycerol system are presented in the form of a complete temperature-composition diagram. This diagram shows the isochronal (10-sec.) mechanical behavior of the system along lines of constant modulus and thereby affords a convenient assessment of variation in viscoelastic behavior along any isotherm or isopleth of interest. Comparison of the results with previously obtained limited sets of data on a number of other polymer-dilent systems indicates the applicability and utility of such a presentation.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060404
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  • 62
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    Ductile behavior of single crystal mats of an ethylene-propylene copolymer (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 707-712 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It is reported that mats formed by the sedimentation of single crystals of methyl- and ethyl-branched polyethylene exhibit strength and ductility comparable with that of melt-crystallized films. In fact, in the case of methyl-branched polymers, extensions of up to 50× were obtained on cold drawing. Observations on separate crystals suggest that this extension is due to the pulling out of individual lamellae. In view of the magnitude of the extension, this implies unfolding of the molecules. That considerable coherence can be obtained without original molecular ties between crystals is of significance as regards the molecular interpretation of the strength and ductility of crystalline polymers.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060406
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  • 63
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    Unperturbed chain dimensions of isotactic polypropylene in theta solvents (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 735-744 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The unperturbed mean-square end-to-end distance 〈R02〉 and its temperature variation d In 〈R02〉/dT for isotactic polypropylene have been estimated from intrinsic viscosity data in three theta solvents, i.e., diphenyl, diphenyl ether, and dibenzyl ether, measured at their θ temperatures as determined by precipitation temperature measurements. The characteristic ratios, 〈R02〉/nl2, where n is the number of bonds of length l in the main chain, evaluated by assuming Φ = 2.87 × 1021, are 5.80 in diphenyl (at θ = 125.1°C.), 5.41 in diphenyl ether (at θ = 142.8°C.), and 4.56 in dibenzyl ether (at θ = 183.2°C.). These values lead to the temperature coefficient d In 〈R02〉/dT = -4.09 × 10-3 deg.-1 Results are compared with the data previously reported on polyethylene.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060409
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  • 64
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    Influence of microstructure on the hydrodynamic behavior of poly-α-methylstyrene (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 499-508 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The theta temperature of poly-α-methylstyrene in cyclohexane has been found to vary with the stereostructure of the polymer. The observed values range from 305.5°K. for highly syndiotactic material (0.95 syndiotactic diads) to 310.0°K. for anio ically polymerized samples (0.67 syndiotactic diads). Results indicate that the unperturbed dimensions of the polymer increase with increasing isotacticity of the chain, whereas the entropy parameter ψ1, measured in cyclohexane, decreased as the structure became more isotactic. Measurements of the second virial coefficient in toluene showed an increasing interaction with the solvent as the polymer became more syndiotactic.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060307
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  • 65
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    Upturn effect in the Non-Newtonian intrinsic viscosity of polymer solutions. II. Polyisobutylene in polybutene oil (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1011-1020 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: With an increasing gradient, the intrinsic viscosity of a high molecular weight polyisobutylene (M̄n = 7 × 106) in polybutene oil L.100 (ηs = 5 poise) first drops to a minimum and then rises again. The minimum occurs at β = M[η]0ηsG/NkT = 240, which is about ten times the value predicted by the dumbbell model. Such a shift to larger gradient is in good agreement with the more realistic necklace model of macromolecules in a good solvent. The increase of intrinsic viscosity after the minimum is nearly linear with the gradient and continues beyond the value at zero gradient. Experiments with capillaries of different length-to-diameter ratios yield identical flow curves so that one may exclude the possibility that the observed upturn is an artifact caused by end effects or time dependence of viscosity.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060519
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  • 66
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    Depolymerization studies on polyacetaldehyde (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1021-1033 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Depolymerization of amorphous polyacetaldehyde has been studied by measurements of weight loss versus time for thin films of the polymer in vacuum. Temperatures ranged from 40 to 80°C. The samples were prepared by freezing or melting the monomer in contact with treated glass surfaces. Light scattering, osmometry, and intrinsic viscosity measurements were used to characterize the polymers. Depolymerization rates were between second and third order with respect to the unvolatilized fraction, and the activation energy was 26.3 kcal. Much of the evidence points toward a slow unzipping reaction at the chain ends, but the analysis seems to be complicated by structural variations among the samples.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060520
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  • 67
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    Anisotropy of viscoelastic transitions in oriented polyethylenes (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1083-1091 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements have been made of the anisotropy of viscoelastic behavior in cold-drawn low-density and high-density polyethylene sheets. In the low-density polymer the β transition was shown to be highly anisotropic, maximum losses corresponding to shear on planes containing the axis of drawing and on planes perpendicular to this axis. In high-density polyethylene the α transition shows anisotropy.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060604
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  • 68
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    Thermodynamic properties of poly(2,6-dimethyl-1,4-phenylene ether) (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1141-1148 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The thermodynamic properties of crystalline and amorphous poly(2,6-dimethyl-1,4-phenylene ether) (PPORegistered trademark of General Electric Company. polymer, General Electric Co.) have been studied calorimetrically between 80 and 570°K. The calculated configurational entropy of this polymer, of similar magnitude to other glass-forming liquids, is consistent with the combination of an unusually high ratio of Tg/Tm, and a low melting entropy.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060607
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  • 69
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    Dynamic analysis of branching in radical polymerizationPaper presented at the 154th Meeting, American Chemical Society, Chicago, September 1967. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1149-1160 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A method for the theoretical analysis of branching in radical polymerization is presented which includes the dynamics of the process. In particular, the method is applied to a polymerization that occurs by decomposition of initiator, propagation, termination by radical combination, and chain transfer with polymer. By a numerical solution of the kinetic equations (suitably transformed), the time dependence of the number-average degree of polymerization (DP), the weight-average DP, the mean number of branches, and the monomer conversion are obtained. The parameters of the process, that is the rate coefficients and initial concentrations, have the following effects: (1) An increase in the chain transfer coefficient increases the ratio of weight-average to number-average Xw/Xn and the mean number of branches Xb, but does not change the number-average Xn. (2) For a given value of the chain transfer coefficient, a change in the parameters of the process such that Xn increases, causes Xw/Xn and Xb to increase also. (3) Chain transfer with polymer seems to produce relatively few polymer molecules having many branches and a large number of smaller polymer molecules having no branches; consequently, the polymer size (or molecular weight) distribution broadens.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060608
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  • 70
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    Skeletal deformation vibrations and rotational isomerism of methylbutenes and methylpentenes as model compounds of 1,4-polyisoprene (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1419-1434 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Infrared spectra of methylbutenes and methylpentenes in the skeletal deformation region have been measured. The force constants for the skeletal deformation vibrations are determined from the frequencies of isobutylene, isobutylene-d6, and methylbutenes. The frequencies of methylpentenes are calculated for the various conformations, and the stable rotational isomers determined. The energy differences between the isomers are determined from the temperature dependence of the spectra. These results are correlated with the conformations of cis-and trans-1,4-polyisoprene chains, and possible conformations are suggested.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060802
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  • 71
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    Growth and drawing of polyacrylonitrile crystals grown from solution (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1381-1399 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyacrylonitrile crystals were grown from dilute solutions of propylene carbonate by a technique similar to that described by Holland et al. Crystals were also grown on various substrates and sampled at various stages of growth after washing away the uncrystallized solution. The initial single lamellae rapidly develop into complex twinned structures with many overgrowths. The morphology of the full-grown crystal varied considerably with crystallization temperature. Small-angle x-ray and electron microscopy results indicate only a small change in lamellar thickness with crystallization temperature for our polymer. Electron and x-ray diffraction results indicate lateral order can be quite good in these crystals. Our x-ray results indicate that the previously reported a and b parameters should be doubled to give a = 21.18 Å and b = 11.60 Å. However, there was no evidence for chain-axis order. The crystals were stretched at various stages of growth on Mylar film. Multilamellar crystals having their long axis parallel to the draw direction formed large cracks perpendicular to the long axis. Fibers of large diameter (100-250 Å) were observed across these cracks. When the long axis of these crystals was at an angle to the draw direction no large cracks or fibers were observed. Single lamellae generally cracked perpendicular to the draw direction, irrespective of their orientation to the draw direction. Definite fibers were not observable across cracks in single lamellae.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060714
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  • 72
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    Fast passage dispersion signals in inhomogeneously broadened electron spin resonance spectra: Application to the measurement of the spin-lattice relaxation times of free radicals derived from esters and salts of poly(methacrylic acid) (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1451-1456 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The shape of the first derivative of the dispersion mode of an inhomogeneously broadened electron spin resonance spectrum changes markedly on saturation. This behavior provides a convenient and rapid technique for estimating the spin latice relaxation time of the paramagnetic species involved. The technique is described together with the relevant theory. Values for the relaxation times of free radicals derived from poly(methyl methacrylate) and from poly(sodium methacrylate) have been obtained by this method and are found to be in good agreement with those obtained by the progressive saturation technique. A series of salts of polymethacrylic acid have been γ-irradiated, and the spin lattice relaxation times of the resulting trapped radicals were determined at 77 and 299°K. For a given polymer the relaxation times show little variation with temperature. This is attributed to a broad distribution of correlation times.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060804
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  • 73
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    Tensile strength of rubbers (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1561-1566 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A current theory of the tensile strength of rubbers invokes large-scale crosslink interchange at room temperature to explain the high tensile strengths of networks crosslinked with weak linkages. This mechanical lability of certain crosslinks has been assumed from their known thermal lability at higher temperatures. Relaxation of stress experiments at various elongations have been performed at room temperature on networks crosslinked with both weak and strong linkages. Our purpose was to detect mechanically induced crosslink slippage. We have found no evidence of any mechanical lability of weak crosslinks at room temperature. A hypothesis is presented which explains the high tensile strengths of rubbers crosslinked with weak linkages as resulting from an internally relaxed network formed by the thermal lability of the crosslinks at the vulcanization temperature. This theory is shown to be consistent with some previously unexplained experimental results.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060901
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  • 74
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    Effects of temperature and water on the γ → α crystalline transition of nylon 6 caused by stretching in the chain direction (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1317-1329 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effects of temperature and water on the crystal transition of nylon 6 from the γ phase to the α phase, which is caused by stretching along the chain direction, were investigated. The γ-phase fibers with high crystallite orientation were stretched at constant load under various conditions. An inversion of the effect of water on the transition occurs at about -60°C. Stretching in the wet state is more effective for the transition at higher temperature. In contrast, at low temperatures water in the crystalline regions actsasa cohesive agent for the chains and increases the activation energy for the transition. Thus, dry stretching is more effective than wet stretching at very low temperature. The fraction of transformed α-phase crystallites increases abruptly over a narrow range of stress. Thus the critical stress can be determined for the transition. The critical stress changes appreciably with temperature; the higher the temperature, the lower the critical stress. The relation between stretching temperature and critical stress was analyzed by Flory's equation for the shift of transition temperature by stress. About 220°C. was estimated as the zero-stress transition temperature. The heat content of the γ-phase crystal was estimated to be smaller by 500 cal./mole than that of the α-phase crystal. This result suggests that the free energy of the γ-phase crystal is lower than that of the α-phase crystal at temperatures lower than the transition point. The irreversible strain of a sample in which the crystal transition has taken place is very small at low temperature. This small extension of the sample is evidence that the γ → α transition produced by stretching along the chain axis is a crystal-crystal transition.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060709
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  • 75
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    Low-frequency losses in rubbers cross-linked in the presence of diluent (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1371-1379 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements of the complex shear compliance have been made from 0.1 to 7 cycles/sec. and from -5° to 45°C. on several samples of natural rubber cross-linked by dicumyl peroxide in the presence of a diluent oil (volume fraction of rubber, v2, = 0.63 and 0.76) which was subsequently extracted. The properties of the extracted vulcanizates were compared with those having the oil still present and with those of conventional undiluted vulcanizates. Measurements of the diffusion coefficient of radioactively tagged n-hexadecane in trace amounts through the polymer structure were also made both before and after extraction of the oil. The diffusion coefficient was higher in the presence of the oil by an amount consistent with the Fujita theory for concentration dependence of diffusion rate based on free volume considerations. The low-frequency mechanical losses (reduced to 25°C. by the method of reduced variables), as measured by the loss tangent, were shifted to higher frequencies by the presence of oil to a much larger degree than would be expected from the difference in local mobility gauged by the diffusion coefficient. The equilibrium modulus, derived by extrapolation to zero frequency, was diminished by the presence of oil to a greater extent than the factor of v2⅓ expected from the simple theory of rubberlike elasticity. The low-frequency losses in the extracted vulcanizates were smaller than those in conventional vulcanizates with comparable degrees of cross-linking; the differences are attributed to differences in network topology.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060713
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    Relation of the decay of free radicals in irradiated polyethylene to the molecular motion of the polymer and the configurations of the free radicals (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1435-1449 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Decay reactions of the free radicals produced in irradiated polyethylene (high-density and low-density materials) were examined in connection with the molecular motion of the matrix polymer. Three temperature regions, in which the free radicals decay very rapidly, at around 120, 200, and 250°K, were designated TA, TL, and TB, respectively. The decay of the free radicals at these temperatures had activation energies in high-density polyethylene of 0.4 kcal/mole for TA, 9.4 kcal/mole for TL, and 18.4 kcal/mole for TB. In low-density polyethylene these quantities were 0.7 kcal/mole for TA, 23.1 kcal/mole for TL, and 24.8 kcal/mole for TB. Comparison of time constants for the decay reactions and for molecular motion of the matrix polymer indicate that the decay in TA and TB is closely related to molecular motion in the amorphous regions of the polymer. The decay of the free radicals at TL in high-density polyethylene is due to molecular motion associated with local mode relaxation at lamellar surfaces, while that of low-density polyethylene is due to local mode relaxation in the completely amorphous region. Steric configurations of the free radicals which decay in the respective temperature regions were also investigated.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060803
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  • 77
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    Basic gel permeation chromatography studies. III. Mathematical analysis of peak spreadingPresented at the Fourth International GPC Symposium, Miami Beach, Fla., May 23, 1967. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1903-1917 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Peak spreading in gel permeation chromatography has been studied with a range of gels including those whose permeation limit corresponded to about 103, 106, 108, and 109 molecular weight polystyrene. Peak spreading conformed to the equation YV2 = YM2 + YA2 + YI2 + YD2 + YS2, where YV is the peak width of a normal chromatogram, YM is the contribution due to the true molecular weight of the sample, YA is due to peak spreading in the apparatus, YI is spreading in the interstitial volume, YD is diffusional spreading due to time spent in the gel, and YS is due to sorption. Evaluating the appropriate parts of the equation leads to measures of the true molecular weight distribution and the contribution due to diffusion into and out of the gel. The data also allowed estimates as to the diffusional spreading with small molecules. With polystyrene having 100 000 molecular weight, diffusional spreading accounts for 80% of YV,2 but with small molecules the contribution due to diffusion was not detected.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160061106
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    Methods of wood chemistry. vol. II. B. L. Browning, Ed., Wiley, New York, 1967. 498 pp. $18.75 (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1943-1944 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160061112
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    Annealing of polybutene-1 single crystals (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1987-1997 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effects of thermal treatment in the 70-90°C. region on polybutene-1 crystals, prepared by precipitation from dilute pentyl acetate solutions and with lath, hexagonal, and square morphologies, have been studied by using electron microscopy. The stability of polybutene-1 crystals to thermal treatment increases in the order: lath 〈 hexagonal 〈 square. Elucidation of the crystallographic directions in unheated lath crystals with respect to the overall morphology was carried out; evidence for restricted folding in these crystals is discussed.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160061204
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    Flow birefringence of short-chain molecules: Cellulose tricarbanilates in benzophenoneDedication to Prof. Husemann, Freiburg, on occasion of the sixtieth anniversity of her birthday, December 27th, 1968. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1953-1974 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements of flow birefringence of cellulose tricarbanilates were carried out on nine fractions (0.27 × 105 〈 M ≤ 12 × 105) in a temperature range of 55-110°C, with benzophenone as a matching solvent (dn/dc = 0). The ratio of Maxwell constant to intrinsic viscosity, which has been found to be independent of molecular weight for the limiting case of Gaussian molecules, is successfully interpreted as a function of molecular weight in terms of the recent theory of Gotlib and Svetlov (based on the wormlike chain model of Kratky and Porod). From the measurements at 55°C a number of 36.6 monomer units per random link is deduced. This is in accord with results of small-angle x-ray scattering. For the extinction angle curves a clear transition is observed from rodlike to statistical molecules when the molecular weight is increased. At high molecular weights the master curves obtained for anionic polystyrenes and cellulose tricarbanilates coincide. Implications of this observation on the kinetic stiffness of the cellulose tricarbanilate chain are discussed. The intrinsic viscosity-molecular weight relationship is considered. From a comparison with the results of the theory of Eizner and Ptitsyn it is concluded that the cellulose tricarbanilate chain must be highly solvated in benzophenone.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160061202
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    Determination of melt viscosity as a function of hydrostatic pressure in an extrusion rheometer (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 2043-2049 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymer melt viscosity was determined as a function of hydrostatic pressure in an extrusion rheometer. An extrusion rheometer consisting of a barrel and a capillary can be looked upon as two capillaries in series. The barrel itself was used as the main viscometer and several different capillaries having length/diameter ratios of 3.5-100 were used as pressure boosters. For a Phillips type polyethylene of 0.95 g/cc density and 0.4 melt index, the apparent viscosity at 190°C and 7.12 sec-1 was increased nearly fourfold as the average pressure in the barrel was raised from atmospheric to 24000 psi. With colored layers of polyethylene as tracers the flow pattern in the barrel was examined. The velocity profiles in the barrel were well developed and parabolic, and thus indicated regular laminar flow under these conditions.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160061208
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    Significant structures theory of the surface tension of polyethylene (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1686-1688 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060914
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  • 83
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    Variation of crystallite orientation with degree of crystallinity: Isotactic polystyrene (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1733-1745 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The orientation of the crystallographic c axis (chain axis) was followed by x-ray diffraction during the crystallization of four samples of isotactic polystyrene differing in elongation ratio. The crystallite orientation can be expressed by 〈cos2 χc〉, where χc is the angle between the c axis and the stretching direction. The degrees of crystallinity w were estimated from the diffraction data by using density for calibration. It was found that 〈cos2 χc〉 decreases in a linear manner with crystallinity, the rate of decrease being very small when the elongation ratio α is 5, but becoming progressively larger as α is decreased toward unity. A qualitative measure suggests that amorphous orientation decreases during crystallization at a rate which is nearly independent of α. The variation of 〈cos2 χc〉 with w is therefore governed by the orientation of the statistical chain segments prior to crystallization. If the elongation ratio is small, the supply of well oriented statistical segments is limited, and 〈cos2 χc〉 will decrease at a rapid rate during crystallization. A treatment due to Krigbaum and Roe permits evaluation of the ratio, ν/N, where ν and N are the average numbers of statistical segments in the crystallization nucleus of critical size, and in a network chain, respectively. Our polystyrene samples were not crosslinked, so chain entanglements must serve as junction points. Values of ν could not be obtained, since N was unknown. However, the (ν/N) ratio for isotactic polystyrene decreases slowly with α, and the values agree reasonably well with those obtained in a previous study of oriented polychloroprene networks. After nearly complete crystallization (ω ca. 0.30), the long period spacing measured by low angle diffraction was approximately 135 Å, and varied only slightly with elongation ratio in the range α = 1 to 5. It therefore appears that chain folded lamellae are present in both drawn and undrawn samples of isotactic polystyrene.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160061004
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    Crystallization kinetics of isotactic polystyrene. I. Spherulitic growth rate (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1791-1801 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The spherulitic growth rate of isotactic polystyrene has been measured in a wide range of temperature by means of a polarizing microscope provided with a hot stage. It was possible to fit the experimental data to theory by choosing a value of 75 for the constant C2 of the WLF equation. The growth rate parameters were compared with those of polyethylene and polychlorotrifluoroethylene. The slowness of crystallization of isotactic polystyrene is mainly a consequence of the lower mobility of the molecules caused by the bulky phenyl groups.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160061009
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  • 85
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    Dielectric properties of poly(vinyl fluoride) (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1813-1816 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160061012
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  • 86
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    Stress relaxation of monodisperse poly-α-methylstyrene (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 129-140 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The viscoelastic properties of monodisperse poly-α-methylstyrenes of molecular weights of 4 × 104 to 50 × 104 were studied by the tensile stress-relaxation method. The relaxation-time spectra as well as the steady-flow viscosity, the steady-state compliance, the maximum relaxation time, and the modulus associated with the maximum relaxation time were determined. The molecular weight dependences of these quantities were compared with the theory of Rouse and Bueche as modified by Ferry, Landel, and Williams, as well as with data on other polymers reported in the literature.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060106
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  • 87
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    Effect of morphology in the surface region of polymers on adhesion and adhesive joint strength (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 231-240 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The morphological character of the surface region of polyethylene has been considered with respect to adhesion and adhesive joint strength. By melting polyethylene onto a high-energy surface (e.g., aluminum) we have provided for extensive nucleation and the formation of a transcrystalline region in the polymer. Dissolution of the metal rather than peeling the metal from the polymer leaves the surface region of the polymer intact. The polymer sheet is now amenable to conventional adhesive bonding and forms a strong adhesive joint. We conclude from this study that the occurrence of the normal weak boundary layer is a consequence of the morphology of the surface region of the material and is, therefore, influenced by the method of preparation.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060113
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  • 88
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    NMR studies of chlorinated poly(vinyl chloride) and polybutadieneA preliminary report of this work was presented at the 15th Annual Meeting of the Society of Polymer Science of Japan held in Nagoya, May 1966. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 223-230 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Molecular structures of chlorinated poly(vinyl chloride) and polybutadiene have been studied by high resolution NMR. The spectra of the chlorinated polymers give broad signals. New peaks appear in the lower fields of the —CH2— and —CHCl— groups with increasing chlorine content. The chlorination of poly(vinyl chloride) takes place predominantly on —CH2— rather than on —CHCl—, e.g., a 70% chlorinated polymer has about 10 mole-% of —CCl2— groups. Polybutadiene reacts first with chlorine by addition to give a head-to-head poly(vinyl chloride), and then the substitution of the hydrogen atom takes place. Chlorinated polybutadiene with 70% Cl has about 18 mole-% of —CCl2—. The multiplets characteristic of spin-spin couplings in the spectrum of the original poly(vinyl chloride) are still observed in that of the highly chlorinated product. This fact shows that a considerable number of poly(vinyl chloride) sequences of certain lengths persist in the highly chlorinated polymer.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060112
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  • 89
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    Dimensional stability of regenerated cellulose film in relation to orientations of crystalline and noncrystalline phasesPaper presented before the 20th Annual Meeting of the Chemical Society, Japan, University of Tokyo, Tokyo, April 2, 1967. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 197-221 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dimensional stability of regenerated cellulose film on swelling with water is discussed in relation to the biaxial orientation of the two kinds of structural units, cellulose II crystallites and noncrystalline chain segments, and their anisotropic swelling (anisotropic absorption of water). Considerable dimensional stability in the plane of the film but enormous instability of thickness on swelling in water of some commercial cellophanes is qualitatively interpreted in terms of the planar orientation of crystal (101) planes along the film surface and the orientation of the noncrystalline chain segments parallel to the film surface. The dimensional changes on swelling from the completely dry state to 10% moisture regain were further interpreted quantitatively in terms of the degrees of biaxial orientation of the two kinds of structural units and their degrees of anisotropic swelling by modifying the Hermans monophase model for crystalline and noncrystalline biphase structures. The following degrees of anisotropic swelling of the structural units were thus obtained: qc, [101] = 0.40%, qc, [101] = -0.33%, and qa = 2.42%.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060111
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  • 90
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    Network relaxation properties of crosslinked poly(ethyl acrylate) and polydimethylsiloxane in the rubbery plateau region (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 259-263 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The stress relaxation properties of poly(ethyl acrylate) and polydimethylsiloxane were investigated under conditions where oxidative degradation was minimized. The relaxation observed is thought to result from the continued approach to equilibrium of the network chains with cooperative thermal motion. These elastomers, representing two new classes of polymer, and two new types of crosslinking, were found to behave surprisingly like natural rubber and butadiene-styrene copolymer. Relaxation was found to obey a power law in time, with a negative exponent of 0.22 for both polymers.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060116
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  • 91
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    Liquid-liquid phase separation in multicomponent polymer solutions. II. The critical state (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 325-347 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Theoretical and experimental evidence is put forward to prove that the determination of the phase-volume ratio as a function of temperature and concentration is a sensitive and simple means of determining the liquid-liquid critical state. Knowledge of the critical conditions permits very accurate calculations of the interaction parameter g in the free-energy function. In experiments with polystyrene-cyclohexane, g was found to depend on the concentration. The value of g and its concentration dependence agree very well with the results of osmotic measurements by Rehage and Palmen. In experiments with polyethylene-diphenyl ether, g proved to be independent of concentration in the range of measurement. The temperature function was found to be: g = -0.6086 + 482.2/T (at 137-148°C.). Gibbs' expressions for the critical conditions were worked out for a free-energy relation in the form of an extended Flory-Huggins function.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060202
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  • 92
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    Liquid-liquid phase separation in multicomponent polymer solutions. III. Cloud-point curves (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 349-366 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Cloud-point curves (CPC) were calculated on the basis of the Flory-Huggins free-energy relation for various hypothetical polymer samples dissolved in a single solvent. Molecular weight distributions varying widely in shape and width were examined. The shape of the CPC reflects details of the molecular weight distribution. This appears from the location of the critical point on the right-hand branch of the CPC. The latter often shows a depression, which becomes more distinct as the Mz/Mw value increases. These theoretical results were confirmed experimentally with the system polyethylene-diphenyl ether. With the aid of the theoretical data collected it was possible to explain the remarkable agreement between the θ temperatures determined by light-scattering and by the Shultz-Flory method. The latter method is basically incorrect, since it identifies the polymer solution with a binary mixture. An explanation could also be given for the empirical relation which McIntyre et al. recently found between the shape of the top of the CPC and the width of the molecular weight distribution.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060203
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  • 93
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    Electric properties of macromolecules. XIII. Transient electric birefringence of sodium polyethylenesulfonate solutions (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 421-431 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The electric birefringence of sodium polyethylenesulfonate in water has been studied. For a low molecular weight fraction, the electric field dependence followed the Kerr law quite closely. For a higher molecular weight fraction, the specific Kerr constant was much larger, and pronounced saturation of the electric birefringence was observed in fields of 15 kv./cm. The specific Kerr constant increased with decreasing polyelectrolyte concentration in pure water. On the other hand, it decreased on isoionic dilution. The saturation effect was the more marked, the lower the polyelectrolyte concentration. The saturation behavior resembled that of permanent dipole orientation, but this mechanism was not supported by the build-up of the birefringence. The magnitudes of specific Kerr constants of various types of macromolecules in solution are tabulated and discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060207
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  • 94
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    Secondary processes of poly(methyl methacrylate) and their activation energies as determined by shear and tensile creep compliance measurementsPresented in part at the 37th Meeting of the Society of Rheology, Atlantic City, New Jersey, October 31-November 2, 1966. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 433-449 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The results of measurement of the shear and tensile creep compliance of poly(methyl methacrylate) between -150 and 75°C. are presented. The master curves show the creep behavior from essentially elastic response to the onset of the α-process. The logarithmic retardation spectra and shear loss compliance reveal two molecular processes, one process being partially obscured by the α-process and therefore not as well defined as the other. These processes manifest themselves as breaks in an Arrhenius plot of the shift factors at about -35 and +25°C. The activation energies in the -35 to 25°C. and 25 to 80°C. ranges are 17.8 kcal./mole and 42.2 kcal./mole, respectively. The former temperature range and activation energy corresponds to the well-known ß-process in poly(methyl methacrylate), the latter to a process which is apparently detectable using various long-time experimental techniques but whose molecular interpretation is at present obscure. The activation energy in the -150 to -35°C. range is about 8.7 kcal./mole.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060301
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  • 95
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    Nuclear magnetic resonance of poly-β-alanine (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 493-498 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Nuclear magnetic resonance of poly-β-alanine samples differing in solubility in water was studied over a wide temperature range as part of an investigation of their physical properties. Water-soluble poly-β-alanine has more branches and a lower degree of crystallinity than water-insoluble poly-β-alanine. NMR spectra of poly-β-alanine show one component at 77°K. which splits into two components, broad and narrow, at room temperature. Two transition regions were observed in curves for line width and second moment versus temperature. The higher transition temperature, corresponding to the glass transition of the polymer, appears to decrease with increasing water content. The second moment for the water-soluble polymer differs from that of the water-insoluble polymer at 77°K. This is interpreted in terms of the difference in the degree of crystallinity of the polymers.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060306
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  • 96
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    Viscoelastic properties of polybutadienes - linear and lightly crosslinked near the gel point (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 479-492 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Viscoelastic properties of four linear and three very lightly crosslinked polybutadienes (microstructure about 50% trans) were studied. Of the latter, two had not reached the gel point, and their molecular weight distributions were determined by sedimentation velocity analysis; the third was crosslinked just past the gel point, with only 32% gel fraction present. The crosslinking agent was sulfur. Complex shear compliances were measured over a frequency range from 0.1 to 1000 cps at temperatures from -70 to 30°C. with a Fitzgerald transducer and a Plazek torsion pendulum; and torsional creep measurements were made over time periods up to about three days. The creep data were converted to the corresponding dynamic viscoelastic functions at very low frequencies by conventional approximation methods. All data were reduced to 25°C. by shift factors calculated from a previously adopted equation of the WLF form. In the transition zone, the viscoelastic properties of linear samples were almost independent of molecular weight. The entanglement spacing, derived from the minimum in the loss tangent and the inflection in the storage compliance, was 130 to 160 chain atoms. The maximum in the retardation spectrum attributable to motions of individual network strands was closely similar to the corresponding maxima for more highly crosslinked vulcanizates previously studied, showing that even in the latter it is associated with entanglement network strands rather than strands between chemical crosslinks. For a linear sample with molecular weight 180,000, the retardation processes disappear at times beyond about 10 sec. at 25°C. With crosslinking short of the gel point (i.e., branching) the slow retardation processes are enormously increased and prolonged to longer times. With further crosslinking through the gel point and beyond, the slow retardation processes decrease progressively in magnitude. Qualitatively, this behavior resembles the sharp maximum in content of highly branched and aggregated molecular species which is predicted at the gel point by crosslinking statistics; but the slow processes (or low-frequency losses) persist farther past the gel point than would be expected on this basis. The steady-state compliances of the linear samples were smaller, but for a sample crosslinked short of the gel point were much larger, than the prediction of the Rouse theory modified for molecular weight distribution.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060305
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  • 97
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    Acetylation of cellulose I and II studied by limiting viscosity and X-ray diffractionPaper presented in part at 153rd meeting of the American Chemical Society in Miami, Florida, April, 1967. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 745-773 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: When cellulose triacetates and some hydrolyzed acetates are boiled in 2.5N hydrochloric acid there is no residue. Under the same conditions cellulose is hydrolyzed, and a residue is obtained with a limiting viscosity that is related to the average length of the cellulose crystallites. These findings are combined to develop a method for studying the progress of acetylation through the amorphous portion of cellulose and into the crystallites, and to investigate the relative reactivities of cellulose I and cellulose II. Acetates were made from cotton and wood cellulose by a “fibrous” (heterogeneous) esterification involving sulfoacetic acid or perchloric acid catalyst in acetic acid-acetic anhydride; the final acetyl contents (10-41%) were attained by stopping the reaction at various points short of the triester (rather than by hydrolyzing a triester). When these acetates were boiled in 2.5N HCI they did not disappear completely, and the residues were cellulose I, indicating that cellulose acetate had been removed. With increasing acetyl the yield of residue decreased, and beyond about 33% acetyl the viscosity and x-ray measurements showed that the length and width of the crystallites decreased. However, when a nonsolvent such as toluene was added to the acetylation medium, the limiting viscosity did not change over the same acetyl range (up to 40%). Samples of varying acetyl values were taken during a regular acetylation of cotton linters in a mixer with sulfuric acid catalyst. X-ray studies of the residues obtained by boiling the acetates in 2.5N HCI revealed the presence of unreacted cellulose I even after 40% acetyl had been reached. This explains why the manufacture of cellulose esters from cellulose I requires complete esterification before they are hydrolyzed to the desired acetyl level. It was shown that there is a distinct difference between the acetylation reactivity of cellulose I and cellulose II. This indicates the importance of avoiding cellulose II formation during the refinement of cellulose for the manufacture of cellulose acetate in a process involving activation with acetic acid.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060410
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  • 98
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    Phase equilibria in polymer-liquid-liquid systems (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 813-823 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The phase equilibria in polymer-liquid 1-liquid 2 ternary systems have been calculated on the basis of the Flory-Huggins theory of polymer solutions. A new approximation method based on the “cluster” concept has been introduced for mixed solvents comprising a solvent and a nonsolvent. This concept has been verified with polystyrene-solvent-methanol systems.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060502
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  • 99
    Electronic Resource
    Electronic Resource
    Melting of polycaprolactam (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 833-848 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Highly crystalline polycaprolactam was prepared by zone polymerization of ε-caprolactam. Folded-chain crystallized and annealed, melt-crystallized, and solution-crystallized polycaprolactam was produced from commercial polycaprolactam. All samples were characterized by x-ray diffraction, electron microscopy, density measurement, and heat of fusion measurement. The determination of the time-dependent melting by DTA and scanning calorimetry revealed that all the different morphologies show different melting behavior. Zone-polymerized polycaprolactam superheats, and the other morphologies reorganize on heating to different degrees. Densities and heat of fusion vary in the same manner - from highest to lowest - in the order: zone-polymerized, solution-crystallized, annealed, and melt-crystallized. An estimate of heat of fusion, equilibrium melting point, and surface free energy was obtained from the melting points.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060504
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  • 100
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    Heat capacities for atactic polystyrene of narrow molecular weight distribution to 360°K. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 849-860 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Precise heat capacity values are reported over the temperature range from 10 to 360°K. for a sample of atactic polystyrene having a narrow molecular weight distribution. This sample was taken from the stock from which National Bureau of Standards Standard Sample 705, Narrow Molecular Weight Distribution Polystyrene, was established. Data are reported for the sample as received, and after an annealing procedure. At temperatures below about 60°K. a systematic difference comparable with the limits of experimental precision appears between the values obtained for the present sample as received and after the annealing, although at higher temperatures the values for the two conditions showed no systematic difference beyond the limits of precision of the measurements. At temperatures above 100°K., previously published values for atactic polystyrene samples of various molecular weight distributions and for isotactic polystyrene agree within about 0.5% of the values from this investigation. At temperatures below 100°K. significant heat capacity differences appear, especially between values for the atactic and the isotactic isomers, and even between atactic samples of different molecular weight distribution.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060505
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