Abstract: It is an effective method that the toughness of polymer-based glass fiber composites is improved by polyethylene glycol (PEG). However，the soft segments of PEG molecular structure have an influence on the thermal properties of composites. In this work，bismaleimide-triazine/glass fiber composites modified by PEG were prepared. The effects of molecular chain length and mounts of PEG on the thermal properties of composites were investigated. The results showed that adding PEG leads to decreases of glass-transition temperature，temperature for the total mass loss of 5%，and the char yield at 800 ℃. There is the highest value of thermal properties，when the molecular weight reaches 4000. Further，the thermal properties of the composites decreased with the increase of PEG amount. The micro-structure analysis showed that the enhanced interface bonding force among PEG，BT resin，and glass fiber are beneficial to the thermal properties，which relaxes the decreased tendency of thermal properties. These results provide a reference for improving the toughness of polymer-based glass fiber using PEG.

Key words: composites, electronic materials, polymers, thermodynamics properties

摘要： 聚乙二醇对树脂基玻璃纤维布复合材料增韧具有优良的效果，但其柔性链段的分子结构本质极大影响了复合材料的耐热性能。本文以聚乙二醇为改性剂制备了聚乙二醇/BT树脂/玻璃纤维布复合材料，系统研究了不同分子链长度以及不同含量的聚乙二醇对复合材料热性能的影响。研究结果表明：聚乙二醇的加入降低了复合材料的玻璃化转变温度、5%热失重温度以及800 ℃残炭率。在聚乙二醇相对分子质量为4000时，复合材料的热性能出现最大值。随聚乙二醇含量的增加，复合材料的热稳定性能逐步下降。由于聚乙二醇、BT树脂、玻璃纤维布之间较大的界面结合力，使基体树脂的链运动受到一定程度的限制，一定程度上缓解了由于聚乙二醇的加入而使复合材料的热稳定性能下降的趋势。研究结果为合理添加聚乙二醇而提高复合材料的韧性提供了热性能方面的参考依据。

关键词: 复合材料, 电子材料, 聚合物, 热力学性质