POSS杂化聚硅氧烷复合材料的制备与热性能研究

Preparation and thermal properties of a functionalized polyhedral oligomeric sitsesquioxane and its methyl polysiloxane hybrid materials

以八乙烯基多面体低聚倍半硅氧烷(OVPOSS)和含氢硅氧烷为单体,通过硅氢加成反应制备了一种新型POSS交联剂V2-POSS。将V2-POSS加入到聚甲基硅氧烷中,制备了一系列不同POSS含量的聚甲基硅氧烷。采用热重分析(TGA)、热重-红外联用(TGA-IR)、裂解气相色谱-质谱(PyGC-MS)等手段对POSS杂化聚甲基硅氧烷的热性能、热分解动力学及动态热解性能进行研究,结果表明:V2-POSS在聚甲基硅氧烷中均匀分散,POSS纳米结构的引入可显著提高聚甲基硅氧烷的热性能;V2-POSS添加量(V2-POSS占聚甲基硅氧烷的质量分数)为10%时,氮气氛5%热失重温度从纯树脂的442.2℃提高至469.4℃;热失重率为15%时,热解表观活化能由纯树脂的87.53kJ/mol提高至杂化树脂的251.12kJ/mol。POSS杂化聚甲基硅氧烷的热解机理主要包括聚硅氧烷主链的断裂、高分子链回咬、含硅基团的重排、碳氢化合物的形成以及小分子的逸出。

A novel polyhedral oligomeric silsesquioxane ( POSS) cross-linker V2- POSS has been synthesized by hydrosilylation of octavinyl-POSS and a hydrogen terminated siloxane ( H2) and incorporated into methyl polysiloxane resins in different ratios by thermal curing technology.The thermal properties,thermal degradation kinetics and pyrolysis behavior of the POSS hybrid methyl polysiloxane were investigated by TGA,TGA-IR,and PyGC -MS. The experimental results showed that V2-POSS could be homogeneously dispersed in the methyl polysiloxane matrix. The thermal properties of methyl polysiloxane were significantly improved by addition of V2-POSS.The 5% weight loss temperature of methyl polysiloxane with 10% V2-POSS increased to 469.4 ℃ in N2 ,27.2 ℃ higher than the corresponding value for the pure methyl polysiloxane resin.The thermal decomposition activation energy of the POSS hybrid methyl polysiloxane increased to 251 kJ /mol compared to a value of 88 kJ /mol for the pure methyl polysiloxane resin when the weight loss ratio was 15%.The thermal degradation mechanism of the methyl polysiloxane includes main chain scission,end-initiated unzipping,rearrangement of silicon-containing groups,formation of hydrocarbons and escape of small molecules.