聚芳醚酮高温长时间下的断裂韧性

THE FRACTURE TOUGHNESS OF POLY(PHENYLENE ETHER KETONE) (PEK-C) AT ELEVATED TEMPERATURE

本文采用三点弯曲测平面应变断裂韧性ＪＩＣ的实验方法，研究了高温（２００℃）长时间放置过程中，聚芳醚酮的高温断裂韧性随时间的变化规律．结果表明，随放置时间的增长，断裂韧性ＪＩＣ和临界塑性屈服区尺寸△ＬＣ都逐渐减小；而屈服强度和抵抗裂纹继续扩展的阻力ｄＪ／ｄ（△ａ）皆增大，且在短时间内有较大增值．从分子运动的角度对上述各物理量的时间依赖性进行了讨论．

-integral method was aPPlied to the amorphous poly (phenylene etherketone ) (PEK - C ), which is a high-Performance POlymer with Tg of 220 ℃ made inthis institutinn. The relationships between reta￣g take at temperature of 200 t withthe yield strength fracture toughness J., critical plastic yielded zone size AL. andresistance to stable crack extension aJ/d(△a) of PEK-C were investigated. Withincreasing the retaining table at 200 t, a pronounced increases of the fold strengthand aJ/d(△a) occur within first a few hours and then only a slow asymptotic approachto equilibrium properties is observed. However the J. and AL. decrease slowly withincreasing the retaining take at 200℃. The take--dependence of folding and fracture behavior at the elevated temperature was discussed based on molecular motion.