Tribological Characteristics of Carbon Nanotube Thermoplastic Resin Composites

Abstract

Wear reduction by Carbon Nanotube (CNT) addition in composites with Ultra-High Molecular Weight Polyethylene (UHMWPE), Polyimide (PI), Polytetrafluoroethylene (PTFE), and epoxy resins have been reported separately. We studied Polypropylene (PP) and Polyamide (PA) composites and showed that with the addition of Multi-wall Carbon Nanotube (VGCF: Vapor Grown Carbon Fiber), wear decreased for PA composites but increased for PP composites. Differences in tribological characteristics of CNT composites with different resins were not well understood. In this paper, we compared tribological and mechanical characteristics of VGCF composites with PE, PP, and Polyacetal (POM) resins. Ball-on-Disk wear tests and mechanical strength measurements were performed. It was found that with the increase in VGCF content, specific wear amount (SWA) of VGCF-PE composite decreased while SWA of VGCF-POM composite stayed almost constant and SWA of VGCF-PP composite increased. On the other hand, with the increase in VGCF content, the tensile strength of VGCF-PE composite was increased but those of VGCF-PP and VGCF-POM composite were decreased. Decrease in SWA of VGCF-PE composite corresponded to the increase in tensile strength with VGCF content. We considered that the intermolecular force between side wall of VGCF and PE was strong enough to make both the SWA small and the tensile strength large.