动态力学分析在氟橡胶热空气老化分析中的应用

Application of dynamic mechanical analysis in analysis of hot air aging of fluoroelastomer

以硫化结构不同的普通氟橡胶及全氟醚橡胶为研究对象,通过动态力学分析研究其热空气老化性能,并结合常规拉伸性能测试对动态力学分析结果进行验证。结果表明,当出现明显的老化现象时,普通氟橡胶及全氟醚橡胶的力学损耗均有明显增大的趋势,同时拉伸强度会出现明显的减小。氟橡胶的硫化结构对其热空气老化性能有重要影响,在250℃下老化24 h后,双酚硫化普通氟橡胶的性能基本无变化,而用过氧化物硫化者出现了明显的老化现象;类似地,在315℃下老化24 h后,用三嗪硫化的全氟醚橡胶仍能基本保持其原有性能,而用过氧化物硫化者的拉伸性能出现了下降。将动态力学分析与常规拉伸性能的测试结合起来,能对氟橡胶的热空气老化行为做出更为立体、全面的描述。

General fluoroelastomer(FKM)and perfluoroelastomer(FFKM)with different vulca-nization structures were selected as the research objects,and their hot air aging properties were studied by dynamic mechanical analysis(DMA),and then the DMA results were verified by conventional tensile properties test.The results showed that the mechanical loss of FKM and FFKM increased obviously and tensile strength decreased obviously when aging phenomenon occured.In addition,the vulcanization structure of fluoroelastomer had an important inf-luence on its hot air aging properties.After aging at 250℃for 24 h,the properties of FKM cured with bisphenol were basically unchanged,while those of FKM cured with peroxide aged obviously.Similarly,after aging at 315℃for 24 h,FFKM cured with triazine could still basically maintain original properties,while the tensile properties of FFKM cured with peroxide decreased.Combined the DMA results with conventional tensile properties test,a stereoscopic and comprehensive description of the hot air aging behavior of fluoroelastomer be given.