MWCNT界面传感器在热塑性复合材料界面监测及自我修复中的应用

Application of MWCNT Interfacial Sensor in in-situ Monitoring and Self-Healing of Thermoplastic Composites

采用纤维/基体界面相填充多壁碳纳米管(MWCNT)技术,探讨水浸泡前后热塑性复合材料界面损伤的原位监测及修复方法。首先,研究了具有最佳性能的MWCNT界面传感器制备方法,确定其最佳工艺参数,并将其植入到纤维/基体界面相中;其次,将试样浸泡在不同温度的水中,研究界面相的吸水行为;再次,开展准静态加载条件下纤维束拔出实验,利用MWCNT的电阻变化原位监测界面相在拔出载荷下的失效过程;最后,通过在界面相中MWCNT的两端施加电压产生电热,原位熔融修复拔出过程中形成的界面损伤。研究结果表明所采用的方法能够得到集抗吸水、原位监测、原位修复功能于一体的多功能热塑性复合材料纤维/基体界面相。该方法可为水浸泡环境中热塑性复合材料的服役安全保障问题提供指导。

In recent years,the development and application of fiber-reinforced thermoplastic resin matrix composites with environmentally friendly and high toughness characteristics have received considerable attention.The fiber/matrix interface bonding properties of thermoplastic composites play an important role in load transfer.However,the water immersion environment can easily cause fiber/matrix interface damage,which seriously threatens its service safety.This article intends to introduce multi-walled carbon nanotube(MWCNT)into the fiber/matrix interface phase in order to explore the in-situ monitoring and self-healing of the interface damage of the thermoplastic composite before and after water immersion.Firstly,the preparation method of the MWCNT interface sensor with the best electrical conductivity is experimentally investigated to determine the optimal process parameters and introduce the MWCNT into the fiber/matrix interface.Secondly,the samples are immersed in water at different temperatures to investigate the water absorption behavior of the interface phase.Thirdly,the fiber bundle pull-out experiment under the quasi-static loading condition is carried out to in-situ monitor the failure process of the interface phase under the pull-out load according to the resistance change of MWCNT sensor.Finally,the interface damage formed during the pull-out process is repaired by in-situ melting using the applied voltage.The results show that the method used in this paper can obtain a multifunctional thermoplastic composite fiber/matrix interface phase that integrates water absorption resistance,in-situ monitoring,and in-situ repair functions.The proposed method provides guidance for the safety of thermoplastic composites in the service of water-immersed environment.