航空聚硫密封剂人工热氧加速老化行为研究

对航空聚硫密封剂进行人工加速热氧老化试验,并采用光学显微镜、光泽度仪、邵氏A硬度计、万能试验机、动态力学分析(DMA)法和红外光谱(FT-IR)法等手段分析了热氧老化对聚硫密封剂的表面微观形貌、硬度、拉伸性能、耐热性和基团特征峰等影响。结果表明:随热氧老化时间延长,聚硫密封剂的光泽度逐渐降低,表面出现明显的泡孔缺陷;当老化时间为20~30 d时,密封剂的拉伸强度和断裂伸长率降幅明显;当老化时间为40 d时,聚硫密封剂的硫化反应更加完全,并且老化期间无可降解新官能团生成,而且其耐热性和室温储能模量基本不变,说明其耐热氧老化性能良好。

Study on artificial accelerated thermo-oxidative aging behavior of polysulfide sealant for aviation

The aging resistance of polysulfide sealant for aviation was tested by artificial accelerated thermo-oxidative aging.And the influences of thermo-oxidative aging on surface microstructure,hardness,tensile properties,thermal stability and group characteristic peaks for polysulfide sealant were analyzed by optical microscope,glossiness meter,Shore A hardness meter,universal testing machine,dynamic mechanical analysis(DMA),infrared spectrum(FT-IR) and other testing meanses.The results showed that the glossiness degree was gradually reduced,and there was obvious bubbly defect on the surface for polysulfide sealant with increasing thermo-oxidative aging time.The tensile strength and elongation at break for sealant were obviously decreased when aging time was 20-30 d.The polysulfide sealant had better post-curing reaction and new degradable functional groups weren’t generated in ageing process,and the polysulfide sealant had good thermo-oxidative aging resistance because its thermal stability and storage modulus at room temperature were almost unchanged when aging time was 40 d.