氰酸酯/环氧树脂共混物热分解动力学

利用动态TGA方法研究了双酚A二缩水甘油醚环氧树脂和酚醛环氧树脂与双酚A二氰酸酯的两类共混物的热稳定性。用Coats-Redfern研究了不同配比共混物的热分解动力学。结果表明,氰酸酯含量大的双酚A二缩水甘油醚环氧树脂/双酚A二氰酸酯共混物具有两阶段分解机理,而环氧含量大的双酚A二缩水甘油醚环氧树脂/双酚A二氰酸酯共混物具有均一的热分解活化能;相比较而言,酚醛环氧树脂/双酚A二氰酸酯共混物的分解活化能基本上不随温度和组成变化。从后期失重温度和活化能看,酚醛环氧树脂/双酚A二氰酸酯共混物具有比双酚A二缩水甘油醚环氧树脂/双酚A二氰酸酯共混物更高的热稳定性。

KINETICS OF THERMAL DECOMPOSITION OF CYANATE/EPOXY BLENDS

Dynamic thermogravimetric analysis (TGA) of two kinds of cyanate/epoxy blends was performed. The effects of molar ratios of cyanate and epoxy on thermal stability were disclosed. Coats Redfern Equation was used to compute the weight loss data and calculate the activation energies of decomposition. It is found that the cyanate rich blends containing bisphenol A diglycidyl ether have a two step decomposition process and epoxy rich blends have a single mechanism. The activation energy of thermal decomposition of the blends containing novolac epoxy, which is greater than that of the blends containing bisphenol A diglycidyl ether, is independent of the temperature and concentration of the epoxy, indicating much better thermal stability than that of the blends containing bisphenol A diglycidyl ether.