PBO纤维纸基复合材料的热老化及高温力学性能研究

Heat Aging and High Temperature Mechanical Properties of PBO Fiber Paper-based Composites

关键词:  PBO纤维纸基复合材料  老化  高温测试  力学性能

Key Words:PBO fiber paper-based composites  aging  high temperature testing  mechanical properties

摘要:本研究采用湿法成形技术制备了聚对苯撑苯并二噁唑（PBO）纸，将其浸渍聚酰亚胺（PI）树脂后，得到PBO纤维纸基复合材料（PBO/PI)，随后对PBO/PI进行300 ℃的老化，并在300 ℃下测试了其拉伸性能。将PBO/PI与模拟蜂窝格壁的间位芳纶浸渍纸（PMIA/PI）进行对比，分析了老化和高温对PBO/PI和PMIA/PI力学性能的影响。结果表明，在300 ℃的高温老化下，由于材料微裂纹的产生及扩展，二者拉伸强度均呈下降趋势，但老化前后PBO/PI的强度均比PMIA/PI更强。动态力学性能显示，老化前后PBO/PI的储能模量大于PMIA/PI的储能模量，说明PBO/PI的刚性比PMIA/PI大，在高温下仍不易发生变形。在300 ℃的高温拉伸测试下，PBO/PI的拉伸强度和保持率均比PMIA/PI要高。PBO/PI在常温及300 ℃高温下的力学性能均优于PMIA/PI，PBO纤维制备的复合材料可用于需要高的抗变形和热稳定性的承重结构和蜂窝部件中。

Abstract:Poly-p-phenylene benzobisoxazole （PBO） paper was prepared by wet forming technology， and then impregnated with polyimide （PI） resin to obtain PBO fiber paper-based composite （PBO/PI）. Then the PBO/PI was aged at 300 ℃， and the tensile properties were tested at 300 ℃. The effects of aging and high temperature on the mechanical properties of PBO/PI and meta-aramid impregnated paper （PMIA/PI） simulated honeycomb lattice wall were analyzed and compared. The results showed that the tensile strength of both PBO/PI and PMIA/PI decreased due to the formation and expansion of microcracks after aging at 300 ℃， whereas the strength of PBO/PI before and after aging was stronger than that of PMIA/PI. The dynamic mechanical properties showed that the storage modulus of PBO/PI before and after aging was greater than that of PMIA/PI， indicating that the rigidity of PBO/PI was greater than that of PMIA/PI， PBO/PI was not easy to deformation at high temperature. The tensile strength and retention ratio of PBO/PI were higher than those of PMIA/PI when they were tested at 300 ℃. The mechanical properties of PBO/PI were better than those of PMIA/PI at room temperature and 300 ℃. The composites prepared by PBO fiber could be used in load-bearing structures and honeycomb parts requiring high deformation resistance and thermal stability.