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电离辐射在工业上应用的基础是聚合物的辐射交联,它们是绝缘电线和电缆的交联,热收缩性材料的生产,泡沫塑料等等。辐射引发交联已经被广泛地研究,特别是凝胶的形成和聚合物结构、辐照条件对交联度的影响。对于一般法和辐射法交联的聚合物却很少有人研究它的结晶过程。例如,已经证明除了在非常高的吸收剂量外,辐照的聚乙烯中总的结晶度不受影响,但对于聚丙烯和聚丁烯在凝胶点剂量时,它们的结晶度大大减少。辐照聚合物的重新熔融,进一步减少了总结晶度。 本工作表明不仅总的结晶度而且结晶动力学也受辐射引发交联的影响。结晶速率指出结晶划分成二种不同增长机理的过程。冷却速率是一个重要的因素,它决定结晶过程并影响与交联的半晶聚合物的结晶度和形态有关的其它性质。
Ionizing radiation is used industrially on the basis of radiation crosslinking of polymers, which are the cross-linking of insulated wires and cables, the production of heat-shrinkable materials, foams and the like. Radiation-initiated cross-linking has been extensively studied, particularly the formation of gels and the effects of the polymer structure and irradiation conditions on the degree of cross-linking. Few people have studied the crystallization process for polymers that have been cross-linked by both general and radiation methods. For example, the total crystallinity in irradiated polyethylene has been shown to be unaffected except at very high absorbed doses, but their crystallinity has been greatly reduced at gel point doses for polypropylene and polybutene. The re-melting of the irradiated polymer further reduces the total crystallinity. This work shows that not only the total crystallinity but also the crystallization kinetics are affected by radiation-induced cross-linking. The rate of crystallization indicates the process by which crystals are divided into two different growth mechanisms. The cooling rate is an important factor that determines the crystallization process and affects other properties related to the crystallinity and morphology of the crosslinked semicrystalline polymer.