碳酸钙晶须增强聚醚醚酮自润滑复合材料的动态力学行为

利用热压成型法制备碳酸钙(CaCO3)晶须和聚四氟乙烯(PTFE)填充的聚醚醚酮(PEEK)基自润滑复合材料.用动态热机械分析仪测试了复合材料的动态力学性能.得到了储能模量、耗能模量及损耗因子随温度变化(25～300℃)的曲线,并和纯PEEK进行比较,分析填充组分对PEEK动态力学性能的影响.结果表明:CaCO_3/PEEK复合材料在玻璃化转变温度(Tg)以下的储能模量比纯PEEK大幅度提高,且随着晶须含量增加而增加;在Tg温度以上,CaCO_3/PEEK复合材料储能模量相对纯PEEK仍保持较高的水平,显著提高了复合材料的高温刚性和热变形温度.加入PTFE使CaCO_3/PEEK复合材料在Tg温度以下的储能模量有所降低,但在Tg温度以上没有衰退.CaCO_3晶须和PTFE的协同作用有助于提高PEEK自润滑复合材料的摩擦学性能.

Dynamic mechanical behavior of CaCO_3 whisker and polytetrafluoroethylene filled polyetheretherketone composites

The composite blocks of polyetheretherketone (PEEK) filled with different content of calcium carbonate (CaCO_3) whisker and polytetrafluoroethylene(PTFE) were prepared by compression molding. Dynamic mechanical thermal analysis(DMTA) was performed on PEEK composites in order to investigate thermally activated molecular relaxation processes and their impact on mechanical properties. Dynamic modulus and mechanical loss factor (tanδ) were continuously measured during a DMTA thermo-sean carried out at 25～300℃. The selected test configuration and operating mode were single cantilever stretching and eanstant-amplitude forced flexuraloscillation, respectisely. The analysis results show that all materials show a large change in storage modulus at the glass transition temperature (Tg). CaCO_3 whisker exhibits an significant effect on dynamic stiffness of the composites at low and high temperatures. The increase of whisker content contributes to a rise of the storage modulus. These modulus of CaCO_3 whisker filled PEEK composites are higher than those observed for pure PEEK, especially below Tg.Addition of PTFE, which is closely related to tribologieal behavior, reduces the storage modulus of CaCO_3/PEEK at temperature below Tg, while the storage modulus above Tg do not change much. These effects in thermal mechanical properties are of benefit to improve tribologieal behavior of the fdled PEEK self-lubricating eompesites.