聚芳醚酮高温长时间下的断裂行为──2．物理老化的影响

THE FRACTURE BEHAVIOR OF POLY (PHENYLENE ETHER KETONE) AT ELEVATED TEMPERATURE FOR LONG TERMS -2. EFFECT OF PHYSICAL AGING

研究了聚芳醚酮在２００℃下长时间放置过程中的密度，热焓，屈服及应力松弛行为随时间的变化规律．结果表明，随放置时间的增长，材料的结构形态与物性随时间的变化速率在１０小时后急剧减慢．文中对物性变化的时间依赖性进行了讨论．在应力松弛过程中出现银纹的现象可归结为物理老化过程中分子链间排列逐渐紧密的结果．

he effeCt of physical aging on the properties of poly(phenylene ether ketone)has been studied. With increasing the aging time at 200 ℃, the stress relaxation rate decreased pronouncedly, while the yield strength, the density, and the excess enthalpy loss increased markedly within the first ten hours. On further aging, only a slow asymptotic approach to equilibrium properties was observed. The time-dependence of the above physical properties was discussed. The occurrence of craze for aged samples during stress relaxation could be attributed to the densification of the glassy matrix in the course of physical aging.