湿热老化对PBO纤维/环氧树脂单向复合材料弯曲性能的影响

Effects of hygrothermal aging on bending properties of PBO fiber / epoxy resin composite

研究了在湿热老化过程中,PBO纤维/环氧树脂单向复合材料弯曲性能的变化规律,发现PBO纤维/环氧树脂复合材料具有不同于一般的纤维增强树脂复合材料的湿热老化特点。研究发现PBO纤维/环氧树脂单向复合材料在湿热老化过程中,相比温度而言,湿度对复合材料弯曲性能的影响更为显著,复合材料在老化过程中吸水率增加的同时,弯曲性能相应降低。其主要原因在于PBO纤维的表面为化学惰性,表面形貌光滑,与环氧树脂浸润性不好,界面粘接力主要是较弱的范德华力。在湿热老化过程中,水分的吸收和渗透造成PBO纤维与环氧树脂基体之间的界面的破坏,构成了该类复合材料独特的湿热老化特性。

The effects of hygrothermal aging on the PBO fiber/epoxy resin unidirectional composites were investigated through studying the bending properties, the surface physical and chemical state of PBO fiber, the water absorption ratio, and the interfacial shear strength of PBO fiber and composites. The results show that the bending properties of PBO fiber/epoxy resin unidirectional composites are more sensitive to the humidity during hygrothermal aging. The bending properties of composites decrease when the water absorption ratio of composites increases during aging. The possible reason is that the surface of PBO fiber is smooth without active groups;the interfacial binding force between PBO fiber and epoxy resin presents mainly Van der Waals force, which is weak and is easy to be broken by water. During hygrothermal aging, the absorption and the penetration of water would result in the sharp decrease of interfacial binding force between fiber and resin and would destruct the bond between fiber and composites. This is the particular character of the hygrothermal aging of PBO fiber/epoxy unidirectional composite.