温度对碳纳米管纤维/环氧树脂界面剪切强度的影响

Temperature effect on interfacial shear strength of carbon nanotube fiber/epoxy resin composites

碳纳米管纤维具有优异的力学、电学和热学性能,是未来高性能多功能树脂基复合材料的理想增强材料.采用微滴包埋实验方法,结合光学显微镜和扫描电子显微镜等表征手段,研究环境温度对碳纳米管纤维/环氧树脂基体间界面剪切强度的影响,并对其机理进行分析.实验结果表明,在室温至140?C环境温度范围内,界面剪切强度随着温度的升高而明显降低.主要原因是:环氧树脂和碳纳米管纤维的热膨胀系数存在较大差异,环境温度升高时界面处发生热失配;高温下树脂基体软化,与纤维的结合力变弱.研究结果对碳纳米管纤维复合材料设计具有重要的指导意义.

Carbon nanotube(CNT)fibers possess excellent mechanical,electrical and thermal properties,such that they have been considered as ideal reinforcement for future high-performance polymeric composites.This study investigates the temperature effect on the interfacial shear strength between CNT fibers and epoxy resin by performing microdroplet tests,and optical/electrical microscopy analyses.It is found that the interfacial shear strength decreases obviously with increasing ambient temperature.This is mainly because the coefficient of thermal expansion of CNT fibers is much lower than that of the resin so that the fiber/resin interface debonds upon heating.Meanwhile,the resin becomes soft at high temperatures,also degrading the interfacial bonding strength.This study provides guidance for the design of carbon nanotube fibers based composite materials.