Dynamic mechanical measurements a t 100 cps were made on homo-, co-, and terpolymers of oxymethylene in the temperature range from -15OoC to the crystalline melting point. The comonomer (ethylene oxide) content was varied from 0 to 5.1 wt.-yo; the terpolymer contained a small amount of a rigid non-crystallizable termonomer. The combined effect of the structural changes and variations in crystallization conditions and annealing provided a range of crystallinity corresponding to densities of 1.396 to 1.435 g/cm3. The y-loss peak located at -60°C remained unaffected by these variations in structure and thermal history. However, the size of the @-loss peak increased uniquely with decreasing density, regardless of how the density was attained. The loss temperature increased from 0 to 10 O C on going from a density of 1.396 to 1.435 g/cm3. The incorporation of a rigid chemical unit raised this temperature by 17°C. The cr-relaxation centered at about 130°C became more prominent with an increase in crystallite size and perfection. A correlation between dynamic mechanical and tensile elongation properties has been obtained. ZUSAMMENFASSUNG:An Homo-, Co-und Terpolymeren des Oxymethylens wurden i m Temperaturbereich von -150 "C bis zum Schmelzpunkt der kristallinen Bereiche dynamisch-mechanische Messungen mit einer Frequenz von 100 Hz ausgefuhrt. Der Comonomergehalt (Athylenoxid) wurde zwischen 0 und 5,l Gew.-yo variiert; das Terpolymere enthielt einen geringen Zusatz eines steifen, nicht kristallisierbaren dritten Monomeren. Durch den kombinierten E i d u B der Anderung der chemischen Zusammensetzung und der Variation der Kristallisations-und Temperbedingungen war es moglich, einen Kristallinitiitsbereich zu erfassen, der Dichten von 1,396 bis 1,435 g/cm3 'entspricht. Das y-Verlustmaximum, welches bei -6OOC beobachtet wurde, wurde durch diese Anderungen der Struktur und der thermischen Vorbehandlung nicht beedul3t. Die Intensitat des p-Maximums dagegen stieg mit abnehmender Dichte einheitlich an, ganz gleich, auf welche Weise der betreffende Dichtewert erreicht wurde. Die Temperaturlage des @-Maximums stieg von 0 bis 10°C an, wenn man die Dichte von 1,396 auf 1,435 g/cm3 erhohte. Durch den Einbau eines steifen Monomeren stieg diese Temperatur urn 17°C. Der cr-Prozel3, der bei etwa 130°C beobachtet wurde, wurde mit steigender KristallitgroBe und wachsender Perfektion der Kristalle immer besser erkennbar. Es wurde eine Beziehung zwischen dem Ergebnis der dynamischmechanischen Messungen und den Resultaten von Spannungs-Dehnungsversuchen gefunden.
To enhance the heat resistance of poly(styrene‐co‐acrylonitrile‐co‐butadiene), ABS, miscibility of poly(styrene‐co‐acrylonitrile), SAN, with poly(styrene‐co‐n‐phenyl maleimide), SNPMI, having a higher glass transition temperature than SAN was explored. SAN/SNPMI blends casted from solvent were immiscible regardless of copolymer compositions. However, SNPMI copolymer forms homogeneous mixtures with SAN copolymer within specific ranges of copolymer composition upon heating caused by upper critical solution temperature, UCST, type phase behavior. Since immiscibility of solvent casting samples can be driven by solvent effects even though SAN/SNPMI blends are miscible, UCST‐type phase behavior was confirmed by exploring phase reversibility. When copolymer composition of SNPMI was fixed, the phase homogenization temperature of SAN/SNPMI blends was increased as AN content in SAN copolymer increased. To understand the observed phase behavior of SAN/SNPMI blend, interaction energies of blends were calculated from the UCST‐type phase boundaries by using the lattice‐fluid theory combined with a binary interaction model. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1131–1139, 2008
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