碳化硼改性酚醛树脂的裂解动力学分析

Pyrolytic kinetics analysis of boron modified phenol-formaldehyde resin

将B4C与酚醛树脂(PF)按一定比例混合并固化形成复合材料B4C-PF。以热重分析为主要手段,分析了B4C-PF的裂解动力学行为。结果表明,裂解反应过程分为两个主要的阶段,前一裂解阶段的代表性机理函数为1-(1-α)1/4,说明决定该阶段反应进程的是B4C的扩散速率。后一裂解阶段的代表性机理函数为(1-α)-2-1,说明决定该阶段反应进程的是B4C与反应物之间的反应活性。后期B4C的扩散速率对反应进程仍有一定的影响。

Boron carbide and phenol-formaldehyde resin were mixed together at some mass ratio. Being cured at 200 ℃,a composite B4C- PF was obtained. Non-isothermal pyrolysis kinetics of B4C-PF was investigated using thermogravimetric analysis( ТGA) at controlled heating rates. The research indicates that the pyrolysis process consists of two stages. In the first stage,the diffusion rate of B4 C was the main factor deciding the velocity of pyrolysis process whose the most probable mechanism function g( α) was 1-( 1- α)1 /4. In the second one,the most probable mechanism function g( α)was( 1- α)- 2- 1,which means the main factor deciding the velocity of pyrolysis process was the reactivity of B4 C and other reactants. At the same time,the diffusion rate of B4 C has some influence on the pyrolysis process.