Simultaneously improving vertical thermal conductivity and oil resistance of carbon fiber reinforced composite through layer-by-layer plasma surface treatment

Abstract

Carbon fiber reinforced composite (CFRC) has attracted considerable attention as a robust high-performance material with outstanding strength-to-weight ratio and is widely used in various applications from aerospace to automotive industries. However, this composite commonly suffers from low vertical thermal conductivity and poor oil resistance, thereby limiting the applicability of lightweight CFRC in metal replacement. Here, we present a facile and effective approach to simultaneously improve vertical thermal conductivity and oil resistance of CFRC on the basis of formation of surficial and interfacial hydrophilic oxide layers in the stacked prepregs using the layer-by-layer plasma surface treatment. Thermally conductive and oil-resistant composite was achieved by simple layer-by-layer plasma surface treatment on individual prepregs and subsequent high-pressure compres-sion of plasma-treated prepregs under elevated temperature. It is experimentally revealed that densely inter-locked laminated CFRC with rough and oxidized multiple interlayers where interpenetrated oxide moieties are vertically distributed minimizes interfacial thermal resistance between stacked prepregs, thereby offering an efficient heat dissipation path in a through-thickness direction. Furthermore, the plasma-induced hydrophilic modification of both surface and interlayer endows the CFRC with excellent oil resistance. Consequently, this facile approach affords high vertical thermal conductivity and remarkable oil resistance, as well as an excellent mechanical strength. Compared to conventional CFRC, our versatile composite accomplishes excellent vertical thermal conductivity with 135% enhancement after oil absorption and outstanding oil resistance with 240% improvement.