氰酸酯改性环氧树脂复合材料的研究

STUDY ON CYANATE ESTER RESIN MODIFIED EPOXY RESIN COMPOSITE

采用双酚A型二氰酸酯对环氧树脂E51进行改性,并制备出玻璃纤维增强复合材料。通过傅里叶红外光谱(FTIR)、动态热力学分析(DMA)对不同质量比的环氧树脂/氰酸酯的共固化产物结构特征以及复合材料的玻璃化转变温度进行了研究,同时测定并讨论了对复合材料的拉伸性能、弯曲性能、吸湿性能的影响。结果表明,在环氧树脂和氰酸酯共固化体系中,随着氰酸酯含量的增加,固化物中三嗪环的相对含量增加,噁唑烷酮的相对含量降低。当环氧树脂/氰酸酯质量比为50/50时,复合材料的玻璃化转变温度为215.6℃,与未改性相比提高了49.7℃;650h后吸水率显著降低,仅为0.69%;但拉伸强度和弯曲强度略有降低。扫描电镜(SEM)分析表明,加入氰酸酯后,增加了复合材料的残余应力,使复合材料呈现出脆性断裂。

The epoxy resin was modified by bisphenl-A dicyanate, and the glass fiber reinforced composites were prepared. The effect of the different mass ratio epoxy resin/cyanate ester resin on the co-cured product structure and glass transition temperature were investigated by fourier transform infrared spectroscopy （FT-IR） and dynamic mechanical analysis （DMA）, tensile property, flexural property and moisture absorption property of the composites were discussed. The results show that, with the increasing of the content of triazine ring, the content of ox- azolidinone decreases as cyanate ester resin increases. When the mass ratio epoxy resin/cyanate ester resin is 50/ 50, the glass transition temperature of the composite is 215.6℃ and increases by 49.7℃ compared to unmodified epoxy resin. After 650 h, water absorption is only 0. 69%, but the tensile strength and flexural strength decrease slightly. Scanning electron microscopy （SEM） shows that the residual stress of composites increase with the incorporation of cyanate ester resin, and composites exhibit brittle fracture.