X-ray Studies on the Mechanical Behavior of Polymer Crystals

用X射线衍射法研究了各种聚合物结晶区的弹性模量及其与温度的关系(从低温到高温)。将结晶模数与结晶区链条的宏观形变和分子运动进行了比较。所研究的聚合物有：纤维素、纤维素三酯、甲壳素、壳聚糖、聚羟基苯甲酸/聚对苯二甲酸乙二酯共聚物、聚对苯二甲酸乙二醇酯、聚对苯二甲酸丁二醇酯、聚对苯撑苯并双恶唑、热塑性聚酰亚胺、联苯型聚酰亚胺、Kapton型聚酰亚胺、三苯基型聚酰亚胺、环状棒状聚酰亚胺、间规聚丙烯、乙烯-乙烯醇共聚物、等规聚乙烯醇、聚乙烯。在一定的温度下，大多数聚合物的晶格模数降低，链状分子在晶格中的分子运动增强。热膨胀系数在该温度附近突然变化，这也与观察到机械弥散的温度范围一致，即所谓的晶体弥散。

Elastic moduli of the crystalline regions of various kinds of polymers and their temperature dependence (from low to high temperature) were investigated by x-ray diffraction. Comparison were made between the crystal modulus with the macroscopic deformation and molecular motions of the chains in the crystalline regions. The investigated polymers were as follows : cellulose, cellulose triesters, chitin, chitosan, poly (hydroxybenzoic acid) /poly (ethylene terephthalate) copolymer, poly (ethylene naphthalate) , poly (butylene naphthalate) , poly (p-phenylene benzobisthiazole) , poly (p-phenylene benzobisoxazole) , thermoplastic polyimide, biphenyl type polyimide, Kapton type polyimide, triphenyl type polyimide, ridid rod-like polyimide, syndiotactic polypropylene, ethylene-vinyl alcohol copolymer, isotactic polyvinyl alcohol, polyethylene.The crystal modulus gives the informaton on the extensivity of the chain molecule, the deformation mechanism in the crystal lattice, the maximum attainable modulus. The crystal modulus decreased at a certain temperature for most of polymers, where the molecular motion of the chain molecules in the crystal lattice enhanced. The thermal expansion coefficient changed abruptly around that temperature, which also coincided with the temperature range where the mechanical dispesion, so-called crystal dispersion, was observed.