聚碳硅烷的热裂解动力学行为研究

Pyrolysis Kinetic Behaviours of Polycarbosilane by Thermal Analysis Method

利用综合热分析和Coats-Redfem动力学模型研究了聚碳硅烷(PCS)的热裂解动力学行为。用X射线衍射、红外光谱分析、扫描电子显微镜等分析技术研究了PCS热裂解过程特点和化学反应机理。结果表明,PCS的热解反应过程以一级热分解化学反应为主。热解过程中升温速率对PCS热解过程和热解产物的显微结构有较大影响,以较低升温速率(2℃/min)热解时,热分解反应的活化能较高,达到16.819kJ/mol,热解后固相残余率小,热解产物的显微结构均匀,表明较低的热解速率有利于PCS充分热解,可以获得结构优良的热解产物。

The thermal analysis technique and the Coats-Redfem kinetic model were used to investigate the pyrolysis kinetic behav- iors of polycarbosilane （PCS）. The reaction kinetic characteristics and reaction mechanism of decomposition of polycarbosilane were analyzed by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The results show that the decomposition reaction of PCS is the first order reaction. The pyrolysis heating rate has a great influence on the kinetic behaviors of decomposition reaction and the microstructure of pyrolysis product. The apparent activation energy of decomposition reaction was greater （16.819 kJ/mol）, the pyrolysis remainder became smaller and the microstructure of pyrolysis product was more uniform at a lower heating rate （2 ℃/min）. It was indicated that the lower pyrolysis heating rate could favor the decomposition reac- tion of PCS and the uniform microstructure of pyrolysis products.