单丝断裂双树脂法研究碳纤维/环氧树脂界面粘结性能

建立了单丝断裂双树脂体系法, 利用外层树脂的韧性使包埋于内层脆性树脂中的纤维单丝断裂达到饱和, 解决了断裂伸长率较低的树脂基体采用传统的单丝断裂法无法测得界面剪切强度的问题。分别采用界面剪切强度和界面断裂能作为表征参量, 考察了干态及湿热条件下两种T300级和两种T800级碳纤维/环氧树脂的界面性能, 并与单丝断裂单树脂体系的界面性能进行比较。结果表明: 单丝断裂双树脂体系与单树脂体系在表征碳纤维/环氧树脂的界面性能上定性规律一致; 双树脂体系界面断裂能和界面剪切强度均可评价界面的耐湿热性能, 且二者得到的变化规律一致; 湿热处理后界面粘结性能均呈下降趋势, 国外碳纤维体系的界面耐湿热性能明显优于国产碳纤维体系。

Characterization of interfacial bonding property of carbon fiber/epoxy resin using single fiber fragmentation test with dual matrix composites

The dual matrix method in single fiber fragmentation test (SFFT) was established which made it possible to obtain the saturated breakpoints of the single fiber embedded in the inner layer brittle resin because of the protection of the outer layer ductile resin. The matrix with low elongation can be used in this method to obtain interfacial shear strength, where conventional SFFT can not work in this case. Interfacial shear strength and interfacial fracture energy were used to investigate carbon fiber/epoxy resin interfacial properties under dry and water aging conditions. Two kinds of T300 grade carbon fiber as well as two types of T800 grade carbon fiber were adopted. The interfacial fracture energies obtained from dual matrix sample and single matrix sample were compared. The results show that the qualitative changes of interfacial adhesion of carbon fiber/epoxy resin in the dual matrix method and single matrix method are similar. The interfacial fracture energy and interfacial shear strength of dual matrix sample can be used to evaluate the moisture resistance of interfacial property, and the changes of the two parameters are consistent. The interfacial adhesions of all studied carbon fiber/epoxy resin decrease after water aging, and the interfacial properties of imported carbon fiber systems are greater than those of national carbon fiber systems.