新型含硅芳基乙炔的固化及成炭机理研究

通过FTIR、DSC、TG和XRD等分析了新型含硅芳基乙炔树脂的组成、固化反应、炭化过程、炭化机理及热分解动力学.结果表明,树脂主链上含有Si元素,在222 ℃发生Diels-Alder固化反应;固化树脂的起始热分解温度为380 ℃,900 ℃的残留率为89.5%.热解动力学分析表明,树脂的炭化分为几个阶段,在250～445 ℃阶段,为引发阶段,结构变化小;450～725 ℃为热分解阶段,聚合物的主链破坏并转变为玻璃态炭结构;在830～855 ℃是芳环发生脱氢交联反应引起的放热阶段;860～895 ℃为碳化物逐渐向乱层石墨结构转变,此阶段以后热稳定性高.XRD和拉曼光谱表明, 1 500 ℃处理后出现SiC峰,2 200 ℃处理后出现石墨峰,表明材料在高温处理时可发生部分石墨化.

Study on curing and pyrolytic mechanism of new PSAA resin

Composition, cure reaction, pyrolytic mechanism and thermal decomposition kinetics of PSAA were investigated by u-sing FTIR,DSC,TG and XRD. The results show that main chain of resin contains Si element, and Diels- Alder cure reaction occurs at 222℃; initial thermal decomposition temperature of cured resin is 380℃,and the char yield at 900℃ is 89.5%. Thermal pyroly-sis kinetic analysis shows that the pyrolytic process of resin could be divided into four steps,i. e. less structure change stage at 250 ～445℃,thermal decomposition stage at 450～725℃,during which main-chain of polymer can be destructed and transited into glass carbon structure,exothermic reaction stage at the 830～855℃ due to aromitic ring dehydrogenation,and the stage at 860～ 895℃,during which the carbide can be changed into random layer graphite structure and the thermal stability becomes higher. XRD and Raman spectra shows that the SiC and graphite peak appear after 1 500℃ and 2 200℃ treatment respectively, which indicates that resin had been graphitized partly during high-temperature treatment.