Tribological and mechanical endowments of polyoxymethylene by liquid-phase exfoliated graphene nanofiller

Abstract

In this study, a viable route to the development of a high-performance polyoxymethylene (POM)-based nanocomposite is proposed to overcome tribomechanical-related issues in high-precision sliding parts. Prior to melt-blending, graphene nanoplatelet (GNP) filler was processed via a series of liquid-phase exfoliation and surface modification with 3-aminopropyltriethoxysilane. Results indicate that GNP is successfully exfoliated with minimum defect ratio and improves interfacial bonding within the matrix. Uniform dispersion and stable load-transfer capability of POM/GNP with 0.5 wt% loading significantly enhanced flexural, tensile and impact strength by overall 26.4%, in contrast to unfilled POM. Dry friction tests against a steel ball also showed the lowest reduction in friction coefficient and wear rate by 22% and 40.6%, respectively, at the same amount of GNP loading due to the large specific surface coverage and lubricious transfer film chelation onto the steel counterface. Furthermore, dissipated energy accumulation by friction work was calculated in the sliding interfaces based on friction force–displacement hysteresis loop where the POM/GNP 0.5 wt% wear surface consumed ca 21.7% less energy in a dry frictional shearing process compared to neat POM. However, lack or excess loading of processed GNP exhibited insufficient or poor matrix–filler adhesion and led to deterioration of the composite properties due to particle agglomeration which can cause stress concentration and serve as a failure site. The adoption of the proposed methodology would demonstrate excellent material characteristics in thin-walled precision parts where both mechanical and tribological performances are the primary concern. © 2024 Society of Chemical Industry.