高温热循环对LP-15聚酰亚胺复合材料界面性能的影响

Influence of High-temperature Cycle on the Interface of LP-15 Polyimide Composites

研究热循环对LP-15/G827聚酰亚胺复合材料界面及其力学性能的影响。结果表明:LP-15浇铸体的热膨胀系数在45×10-6/℃左右,远大于LP-15/G827聚酰亚胺复合材料的热膨胀系数(0.1×10-6/℃～0.3×10-6/℃)。复合材料的层间剪切强度和界面剪切强度均随热循环次数的增加而迅速降低,当热循环次数达到30次以后,层间剪切强度仅能维持在50%左右,而当热循环次数达到80次以后,界面剪切强度仅能维持在20%左右。经扫描电镜研究表明,可能主要是由于上浆剂和树脂基体的降解以及纤维与树脂的热膨胀系数不匹配,导致界面处发生破坏,力学性能下降。

The influence of high-temperature cycle on the interface and mechanical properties of LP-15/G827 polyimide composites were studied.The results showed that the coefficient of thermal expansion(CTE)of LP-15 casting is about 45×10-6/℃,which was bigger than the CTE of LP-15/G827 polyimide composites(0.1×10-6/℃-0.3×10-6/℃).The interlaminar shear strength(ILSS)and the interfacial shear strength(IFSS)of the composites decreased sharply when the times of thermal cycle increased,the ILSS can only maintain about 50% when the times of thermal cycle was 30.However,the IFSS can maintain about 20% when the times of thermal cycle reached 80.From SEM analyzed,the degradation of the sizing and the resin,the mismatch of CTE between fiber and resin were the main reason possibly,so the breakage appeared in the interface and the mechanical properties were decreased.