酞侧基聚芳醚酮冲击断裂韧性的研究

A Study of the Impact Fracture Toughness of Phenolphthalein Polyether Ketone

本文用仪器化冲击仪研究了酞侧基聚芳醚酮（ＰＥＫ－Ｃ）的冲击断裂韧性对温度的依赖性。依据线弹性断裂力学原理，通过１．５ＹＰＬ／ＢＤ２对ａ－１／２作图，所得直线斜率即为应力强度因子Ｋｃ；用Ｕ对ＢＤΦ作图，所得直线斜率即为扩展裂纹所需的能量Ｇｃ。在不同温度下测试，便可得到Ｋｃ－Ｔ，Ｇｃ－Ｔ的依赖关系图。温度对冲击断裂韧性的影响，是ｔａｎδ损耗和裂尖前缘热钝化共同作用的结果。在１００～１４０℃之间，断裂韧性的升高主要是由于β转变作用的结果。通常ｔａｎδ对能量吸收过程的影响，要比裂尖前缘热钝化的影响小，只有当裂尖前缘区域的有效温度Ｔｅ低于软化温度Ｔｓ时，ｔａｎδ才起作用。当Ｔ＝１８０℃，Ｔｅ＝２０２．４３℃，大于软化温度Ｔｓ时，裂尖前缘热钝化开始起作用。

The temperature dependence of impact fracture toughness of phenolphthalein polyether ketone(PEK-C) was studied by using an instrumented impact tester.On the principle of linear elastic fracture mechanics,the stress strength factor K c was the linear slope in the graphic chart of 1.5 YPL/BD 2 vs a 1/2 ,and the crack expanding energy G c was the linear slope in the graphic chart of U vs BDΦ .The dependence of K c on T and G c on T could be obtained by determinations at different temperatures.The effect of temperature on impact fracture toughness was a result of the joint effect of tan δ loss with crack tip thermal blunting.When the temperature was 100～140℃,the increase of fracture toughness was mainly a result of β transition.The effect of tan δ on energy absorption was usually smaller than that of crack tip thermal blunting on energy absorption.Only when the effective temperature T e was lower than softening temperature T s, tan δ had its effect on the toughness.When T s was 180℃, T e was 202.43℃,higher than softening temperature T s,crack tip thermal blunting had its effect on the toughness,and the toughness increased with the increase of temperature.