Investigation of solid-state transitions in linear and crosslinked amorphous polymers
Investigation of solid-state transitions in linear and crosslinked amorphous polymers
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线性和交联无定形聚合物中固态转变的研究
DOI：
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发表时间：
2005
期刊：
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通讯作者：
J. Halary
中科院分区：
文献类型：
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作者：
L. Monnerie;F. Lauprêtre;J. Halary
本文讨论了非晶态聚合物在低于玻璃-橡胶转变温度下观察到的导致固态转变的分子运动的主要特征的测定和分配。首先，这些二次转变的具体特征(β，y，δ，...)都作了简要的描述。然后分析了各种聚合物体系的行为：聚(环烷基甲基丙烯酸酯)及其环内运动、聚对苯二甲酸乙二酯和双酚A型聚碳酸酯的β转变以及小分子抗塑剂、芳基-烷基聚酰胺转变、聚甲基丙烯酸甲酯及其马来酰亚胺和戊二酰亚胺无规共聚物的β转变的影响。此外，含有或不含有抗塑化剂的线性聚合物，芳基-脂肪族环氧树脂体系，说明了交联型无定形聚合物的情况。虽然所有的体系都是通过动态力学测量和13C固体核磁共振实验来研究的，但有些体系也是通过介电松弛和分子模拟等技术来研究的。聚甲基丙烯酸甲酯和双酚A聚碳酸酯是描述β转变中所涉及的分子运动的最好例子，特别是在转变的高温部分发展的协作性的性质和程度。这是通过结合现有的所有实验和建模技术来实现的。
This paper deals with the determination of the main characteristics and the assignment of the molecular motions leading to the solid-state transitions observed in amorphous polymers at temperatures lower than the glass-rubber transition. First, the specific features of these secondary transitions (β, y, δ,...) are briefly described. Then, the behaviour of various polymer systems is analysed: poly(cycloalkyl methacrylates) and their intracycle motions, poly(ethylene tere-phthalate) and bisphenol A polycarbonate β transition and the effect of small molecule antiplasticisers, aryl-alkyl polyamide transitions, the β transition of poly(methyl methacrylate) and its maleimide as well as glutarimide random copolymers. Additionally linear polymers, aryl-aliphatic epoxy systems, with or without antiplasticisers, illustrate the case of crosslinked amorphous polymers. Whereas all the systems considered were investigated by dynamic mechanical measurements and 13 C solid-state nuclear magnetic resonance experiments, some systems were also studied by other techniques such as dielectric relaxation and molecular modelling. Poly(methyl methacrylate) and bisphenol A polycarbonate constitute the best examples of the level of description of the molecular motions involved in the β transition and, in particular, the nature and extent of the cooperativity which develops in the high-temperature part of the transition. This is achieved by combining all the experimental and modelling techniques presently available.