航空聚硫密封剂人工热氧加速老化行为研究

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

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（rr—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20～30d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40d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。

The aging resistance of polysulfide sealant for aviation was tested by artificial accelerated thermooxidative 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 speetrum（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.