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  • 1
    Digitale Medien
    Digitale Medien
    Secondary mechanical relaxation effects in some cycloalkyl side groups containing polymers (1966)
    Springer
    Colloid & polymer science 213 (1966), S. 115-120 
    Details
    ISSN: 1435-1536
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Es wurden die dynamischen Eigenschaften im akustischen und im Bereich langsamer Ultraschallfrequenzen (6–60 kHz) untersucht für Polycyclopentylmethacrylat (PCPMA), Polycyclohexylmethacrylat (PCHMA), Polycycloheptylmethacrylat (PCHpMA), Polycyclooctylmethacrylat (PCOcMA), Polycyclohexylacrylat (PCHA), Polyvinylhexahydrobenzoat (PVHHBz) Polyvinylcyclohexyläther (PVCHE) und Polyvinylcyclohexan (PVCH). Die Untersuchungen wurden mit einer elektrostatischen Methode (Biegeschwingung) über den Temperaturbereich von 60 °K bis Raumtemperatur durchgeführt. Alle Polymeren, außer Polyvinylcyclohexanen, zeigen eineγ-Relaxation verbunden mit internen Bewegungen des Cycloalkylrings, deren Aktivierungsparameter wesentlich von der Natur des Rings abhängen. PVCHMA, PVCHA, PVHHBz, PVCHE und PVCH zeigen einen weiteren sekundären Relaxationseffekt (δ-Prozeß) bei tieferen Temperaturen, dessen Lage in der Temperaturskala, Stärke (Peakhöhe) und Aktivierungsparameter von der Natur der Einheiten abhängen, an welchen der Cyclohexylring hängt. Derδ- Prozeß wird irgendeiner komplexen Bewegung des ganzen Cyclohexylrings zugeschrieben, eingeschlossen oszillatorische Rotation desselben um die Einfachbindung, die ihn mit der Hauptkette verbindet. Anders als derδ-Prozeß der Phenylseitengruppen enthaltenden Polymerenketten scheint der hier untersuchteδ-Prozeß emfindlicher von intramolekularen Effekten abzuhängen.
    Notizen: Summary The dynamic mechanical properties at acoustic and low-ultrasonic frequencies (6–60 kHz) have been determined in polycyclopentylmethacrylate (PCPMA), polycyclohexylmethacrylate (PCHMA), polycyclohepthylmethacrylate (PCHpMA), polycyclooctylmethacrylate (PCOcMA), polycyclohexylacrylate (PCHA), polyvinylhexahydrobenzoate (PVHHBz), polyvinylcyclohexylether (PVCHE) and polyvinylcyclohexane (PVCH) Measurements were carried out by an electrostatic method (flexural vibrations) over the temperature range 60 °K to room temperature. All polymers, except for polyvinylcyclohexane, exhibit aγ-relaxation, connected with internal motion of the cycloalkyl ring, whose activation parameters depend exclusively on the nature of the ring. PVCHMA, PVCHA, PVHHBz, PVCHE and PVCH exhibit a further secondary relaxation effect (δ-process) at lower temperature, whose position on the temperature scale, strength (peak height) and activation parameters depend on the nature of the units to which the cyclohexyl ring is attached. Theδ-process is attributed to some complex motion of the whole cyclohexyl ring, involving oscillatory rotation of the same around simple bonds which link it to the backbone chain. Contrarily to theδ-process of the phenyl side group containing polymers, theδ-process of the polymers here examined seems to be more sensibly dependent on intramolecuar effects.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01552520
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  • 2
    Digitale Medien
    Digitale Medien
    Group motions in the glassy state of some substituted polystyrenes and poly(vinyl benzoates) (1966)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 4 (1966), S. 789-796 
    Details
    ISSN: 0449-2978
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Mechanical damping measurements were carried out in the range of 103-105 cps and between 60°K. and the softening point on some substituted Polystyrenes and poly(vinyl benzoates) containing different substituents (methyl groups, methoxy groups, and halogen atoms) either in the ring or in the main chain. The ortho and meta ring-substituted polystyrenes do not show any secondary mechanical relaxation in the glassy state, although all the other substituted polystyrenes, exhibit a low-temperature damping peak (δ process) (which is in some way connected with ring motions) whose height and temperature location depend on nature, position, and number of substituents. Substituents in the para position of the ring or in the α position in the backbone chain shift the δ peak of the unsubstituted polystyrene towards higher temperatures; this shift is accompanied by an increase of the apparent activation energy E*. Substitution in the β position, on the contrary, does not affect the δ peak. Analogous results are obtained for substituted poly(vinyl benzoates), which exhibit, in addition, a β relaxation effect, associated with carboxyl group motions. A very good correlation is found between the values of E* and the limiting relaxation time τ for the δ relaxation of polystyrenes and poly(vinyl benzoates), similarly substituted in the ring, indicating that the δ relaxation leads to absorption curves in the mechanical relaxation spectrum which are characteristic of the structure of the aromatic side chain.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pol.1966.160040510
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  • 3
    Digitale Medien
    Digitale Medien
    Effects of nuclear radiations on structure and molecular motions in some crystalline stereoregular polymersPaper presented at the XX IUPAC Congress, Moscow, July 12-18, 1965.Prod. No. 1312 (1966)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 10 (1966), S. 399-419 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Young's modulus and the mechanical damping factor have been determined between -180 and +280°C. (at a frequency of several kilocycles), in samples of isotactic polypropylene, isotactic polystyrene, and trans-1,4-polybutadiene, subjected to pile irradiation (γ-rays and neutrons) at γ-doses from 90 to 4000 Mrad. In isotactic polypropylene no important structural changes are produced by the irradiation, except for a partial destruction of crystallinity. The samples receiving high radiation doses exhibit a low temperature loss region, which is attributed to the formation of a certain number of branches. Isotactic polystyrene shows very slight modifications of the dynamic mechanical properties at room temperature. At low temperature an increase of intensity of the δ relaxation phenomenon (probably due to oscillations of phenyl rings) with increasing radiation dose is observed. Important structural modifications produced by the radiation, destruction of crystallinity accompanied by crosslinking, which transform the material into a crosslinked rubber, are observed in trans-1,4-polybutadiene. Unlike conventional (sulfur) vulcanization, crosslinking by radiation does not cause a marked shift of the glass transition point. A secondary low-temperature relaxation effect, not existing in the unirradiated material, appears in the mechanical loss curves of the irradiated samples; it is attributed to the formation of —CH2—sequences in the main chains through saturation of C=C bonds. The mechanical spectrum of irradiated polybutadiene is very similar to those shown by crosslinked ethylene-butadiene copolymers.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1966.070100305
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  • 4
    Digitale Medien
    Digitale Medien
    Mechanical secondary relaxation effects in polysulfone (1967)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 1296-1299 
    Details
    ISSN: 0449-2978
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pol.1967.160050624
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  • 5
    Digitale Medien
    Digitale Medien
    Use of the dielectrometer for the determination of the complex dielectric constant in the microwave region in organic high polymers at various temperatures (1966)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 10 (1966), S. 1067-1088 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: A commercial type dielectrometer has been utilized for determining the complex dielectric constant of insulating materials as a function of temperature. For low-temperature measurements, modifications of the apparatus have been made, by which the lower section of the guide, containing the specimen, is insulated from the upper section by means of a Teflon disk, in order to permit measurements under vacuum without difficulties arising from moisture condensation. Taking into account the modifications made, relations between the experimentally measured quantities and the complex dielectric constant have been elaborated, and error analysis made, and best conditions to perform experimental measurements determined. For high- and medium-loss materials, in the low-temperature range, an accuracy of the order of 1% in ∊′ and of 10% in ∊″ have been calculated. Better results can be obtained for measurements at high temperature. The apparatus performance and the accuracy of measurements have been checked through measurements of the complex dielectric constant of different polar polymers at frequencies of the order of 9 × 109 Hz, at temperatures between -150 and 200°C. The experimental results are in good agreement with literature data derived from experimental measurements with other techniques and with the behavior expected on the basis of the results from radiofrequency measurements through considerations of molecular mobility in relation to molecular structure.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1966.070100709
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  • 6
    Digitale Medien
    Digitale Medien
    Young's modulus and secondary mechanical dispersions in polypromellitimide (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 1073-1081 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Dynamic mechanical properties were determined in polypyromellitimide at acoustic frequencies over a wide temperature range (80-750°K). Two distinct secondary relaxation effects were found: one (β′) at lower temperature, characterized by a loss maximum at 250°K, and another (β) at higher temperatures with a loss maximum at 400°K. The lower temperature peak is shifted towards higher temperature with increasing frequency following an Arrhenius-type equation (apparent activation energy: 15 kcal/mole); the relaxation strength increases with water content and becomes practically zero when samples dried under vacuum at 200°C are examined. The β′ relaxation process is thus attributed to the presence of adsorbed water molecules. The higher-temperature (β) dispersion, which persists even after dehydration, on the basis of some results obtained for other polymers containing p-oxylphenylene rings in the backbone, is tentatively attributed to torsional oscillations of aromatic rings along the chain.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1969.070130601
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  • 7
    Digitale Medien
    Digitale Medien
    Dielectric behavior of some polar high polymers at ultra-high frequencies (microwaves)Prod. No. 1475 (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 527-551 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The dielectric behavior of different polar high polymers at ultra-high frequencies has been investigated by means of a dielectrometer, suitably modified to permit measurements at different temperatures. Experimental measurements were made at about 9 × 109 cps over the temperature range of -150 to 200°C. for polyoxymethylene, polythiomethylene, poly(3,3′-chloromethyl)oxetane (Penton), polycarbonate of 4,4′-dioxydiphenyl-2,2′-propane (Makrolon), poly(vinyl alcohol), poly(vinyl acetate), poly(vinyl chloride), vinyl chloride-vinyl acetate copolymer, and two ABS plastics, type B (blend) and type G (graft). On comparing the dielectric behavior of the examined materials at ultra-high frequencies with the corresponding ones determined at low or at radiofrequencies, it is observed that, in the microwave region, all relaxation peaks, either connected with cooperative motions in main chain (primary processes) or with local motions in the backbone or in side chains (secondary processes), usually observed at lower frequencies, tend to disappear; the corresponding relaxation effects, however, manifest themselves through a progressive increase of losses with increasing temperature, which is particularly marked above the glass transition temperature Tg. The latter transition, in spite of the very high frequency, is easily distinguished, in most cases, by the sudden change of slope in the tan δ versus temperature curve which accompanies its onset. This is explained on the basis of the very wide distribution times of molecular relaxation processes in polymers and the increase in strength of the secondary relaxation effects, which is verified at Tg, as a consequence of the increased kinetic energy of macromolecules and of the larger free volume for orientation of side chains. Each case is discussed separately and the experimental results interpreted on the basis of the molecular structure and chain mobility of the examined polymers.
    Zusätzliches Material: 21 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1967.070110404
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  • 8
    Digitale Medien
    Digitale Medien
    Molecular motions in amorphous random ethylene-propylene copolymersDedicated to Prof. G. NATTA on the occasion of his 60th birthday (1963)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 61 (1963), S. 14-21 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Dynamisch-mechanische Eigenschaften (Schallgeschwindigkeit v und Dämpfungsfaktor Q-1) wurden in einigen amorphen “random” Äthylen-Propylen-Copolymeren mittels einer elektrostatisch-dynamischen Methode bei Frequenzen von etwa 104 Hz im Temperaturbereich von -170 bis -15°C bestimmt.Bei allen Proben findet man zwei Temperaturen, T′g (-120°C) und Tg (-30 bis -55°C), bei denen die v-T-Kurven einen Knick zeigen, sowie zwei Dispersionsgebiete in den Q-1- T-Kurven.Die Umwandlung bei T′g und das Dispersionsgebiet bei niedriger Temperatur werden der Bewegung der —CH2-Gruppen der Hauptkette und einer beschränkten Anzahl von Kettenteilen mit seitlichen CH3-Gruppen zugeordnet. Die Umwandlung bei höherer Temperatur wird der Bewegung von längeren Segmenten der Hauptketten zugeordnet.Die experimentellen Ergebnisse werden auf Grund der Struktur der Äthylen-Propylen-Copolymeren diskutiert.
    Notizen: Dynamic mechanical properties (sound velocity and damping factor Q-1) have been determined in some amorphous ethylene-propylene copolymers from -170 to -15°C. by an electrostatic method at a frequency of the order of 104 Hz.Two abrupt changes of slope are observed in the v - T curves, one at T'g (-120°C.) and one at Tg (-30 to -55°C.) and two regions of high dissipation are noticed in the Q-1-T curves, one at temperatures between T'g and Tg and one at temperatures above Tg.The transition at T'g and the lower temperature relaxation phenomenon are both attributed to molecular motions of —CH2— groups in the main chain and of a limited number of chain elements containing CH3 branching. The transition at Tg and the higher temperature relaxation phenomenon are connected with motions of large sections of the chain.The experimental results are discussed on the basis of the structure of ethylene-propylene copolymers and suggestions are made concerning the use of dynamic mechanical data for the characterization of these materials.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1963.020610102
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  • 9
    Digitale Medien
    Digitale Medien
    Polymerization by crystallization of molten trioxane suspended in inert media, in presence of ethylenoxideDedicated to Prof. Dr. W. KERN on the occasion of his 60th birthday (1966)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 93 (1966), S. 137-144 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Die Methode, Trioxan, während es aus einer abkühlenden Lösung auskristallisiert, zu polymerisieren, wird auf die Copolymerisation von geschmolzenem Trioxan mit Äthylenoxid mittels BF3-Ätherat in Suspension in mit Polyisobutylen verdicktem Mineralöl übertragen. Mit ca. 4·10-5 Mol Initiator/Mol Trioxan entstehen Copolymere mit überwiegender Polyoxymethylen-Struktur in 45 bis 60% Ausbeute, welche sich durch hohe Molekulargewichte (ηinh = 1,5 bei 60°C in 0,5-proz. Lösung in p-Chlorphenol) und durch hohe thermische Stabilität (Gewichtsverlust bei 220°C unter Stickstoff = 0, 03%/Min.) auszeichnen.
    Notizen: The method of polymerization of trioxane solutions during crystallization by cooling is extended to molten trioxane in presence of ethylenoxide, suspended in mineral oil (thickened with polyisobutylene) and activated with small quantities of BF3·Et2O. Operating with quantities of catalyst in the order of 4.0/10-5 moles/mole of trioxane, copolymers with prevailing polyxymethylene structure are obtained, characterized by high molecular weight (ηinh = 1.5 in 0.5% solution in p-chlorophenol at 60°C.) and good thermal stability (k220 = 0.03%/min.), with yields of 45 to 60%.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1966.020930109
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  • 10
    Digitale Medien
    Digitale Medien
    Sound velocity and damping in ziegler polythene (1957)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 25 (1957), S. 239-242 
    Details
    ISSN: 0022-3832
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pol.1957.1202510916
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