Achieving electrical insulation, high thermal conductivity and high fracture toughness in polyamide 6/carbon nanofiber composites through the interfacial welding effect of elastomer

Abstract Interfacial interaction exhibits important role in determining the performance of polymer composites, especially at high filler content. In this work, illuminated from the braze welding technology that is applied to joint different metals using the welding stick with relatively high plastic deformation ability or high toughness, a new concept of ‘interfacial welding’ was proposed to engineer the strong interfacial interaction of the thermally conductive composites. A commercial elastomer, i.e. anhydride-modified ethylene-based copolymer (AEC), was incorporated into the polyamide 6 (PA6)/carbon nanofibers (CNFs) composites. Due to the presence of the insulating AEC and the stronger interfacial affinity between CNFs and AEC, the ternary PA6/CNF/AEC composite samples showed largely enhanced electrical resistance and comparable thermal conductivity compared with the binary PA6/CNF composite samples. Specifically, largely enhanced fracture toughness was achieved for the ternary composite samples. The concept of ‘interfacial welding’ may be extended to fabricate the other composites with excellent comprehensive performances.