Simultaneous enhancement of electrical conductivity and interlaminar fracture toughness of carbon fiber/epoxy composites using plasma-treated conductive thermoplastic film interleaves.

Wei Li,Eileen Harkin-Jones,Lei Wang,Dong Xiang,Bin Wang,Chunxia Zhao,Yuntao Li

doi:10.1039/c8ra05366a

Abstract

Multiwalled carbon nanotube (MWCNT)-doped polyamide 12 (PA12) films with various nanofiller loadings were prepared via a solution casting method to simultaneously improve the electrical conductivity and fracture toughness of carbon fiber/epoxy (CF/EP) composites. The films were interleaved between CF/EP prepreg layers and melted to bond with the matrix during the curing process. To improve the interfacial compatibility and adhesion between the conductive thermoplastic films (CTFs) and the epoxy matrix, the CTFs were perforated and then subjected to a low temperature oxygen plasma treatment before interleaving. Fourier transform infrared (FTIR) spectra results confirm that oxygen-containing functional groups were introduced on the surface of the CTFs, and experimental results demonstrate that the electrical conductivity of the laminates was significantly improved. There was a 2-fold increase in the transverse direction electrical conductivity of the laminate with 0.7 wt% MWCNT loading and a 21-fold increase in the through-thickness direction. Double cantilever beam (DCB) tests demonstrated that the Mode-I fracture toughness (GIC) and resistance (GIR) of the same laminates significantly increased by 59% and 113%, respectively. Enhancements of both interlaminar fracture toughness and electrical conductivity are mainly attributed to the strong interfacial adhesion achieved after plasma treatment and to the bridging effect of the carbon nanotubes.

Highlights

In recent years, there has been much interest in developing composite materials for large primary structures on military and civil aircra in order to achieve lighter structures for signi cantly reduced fuel consumption and reduced environmental impact
Experimental results show that electrical conductivities in the Y and Z-directions of laminates interleaved with 10 wt% Multiwalled carbon nanotube (MWCNT)-doped lm a er plasma treatment increased 2-fold and 21-fold, respectively, compared to the control sample
This is attributed to the increased dispersibility of carbon nanotubes (CNTs) in the resin matrix because of better dissolution of the doped lm in the composite system, and this further reduced the resistance of the resin-rich region

Summary

Introduction

There has been much interest in developing composite materials for large primary structures on military and civil aircra in order to achieve lighter structures for signi cantly reduced fuel consumption and reduced environmental impact. There are increasing demands for CF/EP composites in the aerospace eld.[1] It has been reported that the amount of composite material used in a Boeing 787 Dreamliner and Airbus A350 XWB accounts for more than 50% of the aircra 's structural weight, and this greatly reduces fuel consumption (by 20%) as well as production and maintenance costs.[2,3,4]. CNTs exhibit extraordinary electrical conductivity and have mechanical properties that make them one of the most suitable conductive llers for preparing conductive polymer composites.[13,14,15,16] the high aspect ratio and strong van der Waals interactions between nanoparticles cause severe aggregation and poor dispersion, which may lead to adverse consequences

Methods

Results

Conclusion