含硅氧烷结构聚酰亚胺树脂的耐热稳定性及高温结构演变

Thermal Stability of Polyimide Resins Containing Siloxane Structure and Their High Temperature Structural Evolution

基于含硅芳香二胺双(4-氨基苯氧基)二甲基硅烷(APDS)设计制备了系列苯乙炔基封端的含硅氧烷结构聚酰亚胺树脂预聚物(PEPA-PIS),考察了硅氧烷含量对树脂固化物耐热稳定性的影响规律.利用非反应性苯酐基团封端的模型预聚物(PA-PIS)证明了温度对于硅氧烷结构演变的影响.通过对树脂固化物高温固化处理后耐热稳定性与微观结构和表面形貌的关系进行深入研究,发现在高温下硅氧烷结构发生氧化交联反应,并在树脂表面形成具有无机特性的二氧化硅结构,这种有机/无机杂化特性可显著提高聚酰亚胺树脂的耐热稳定性.

A series of phenylethynyl-terminated imide oligomers( PEPA-PIS) based on siloxane-containing aromatic diamine,i.e.,bis( p-aminophenoxy) dimethyl silane( APDS),was synthesized. The effect of siloxane content on the thermal stability of cured polyimides resins was investigated. The influence of temperature on the evolution of siloxane structure was confirmed by the non-reactive phthalic-terminated model imide oligomers( PA-PIS). The thermal stability of polyimide resins after post-curing at elevated temperature and the correlation with the microstructure and surface morphology were discussed. The results indicated that the oxidative crosslinking reaction of siloxane was occurred at elevated temperature,and even resulting in the formation of inorganic silica on the resin surface. The significant enhancement in thermal stability of polyimide containing siloxane structure is attributed to their organic/inorganic hybrid characteristics.