Mechanical, wear and fatigue behavior of functionalized CNTs reinforced POM/PTFE composites

Abstract

The main focus of this work is to improve the strength, stiffness, wear resistance and fatigue strength of polyoxymethylene (POM). For this purpose, POM is incorporated with a lubricating additive polytetrafluoroethylene (PTFE) and reinforced with silanized multiwalled carbon nanotubes (CNTs). PTFE filled POM composites with varying weight fraction of PTFE and hybrid composites with 1 wt% silanized CNTs and varying weight fractions of PTFE were fabricated by melt compounding using a twin screw extruder followed by injection molding. Tensile, flexural, wear and fatigue behavior of the developed composites were evaluated. Incorporation of PTFE resulted in a significant decline of tensile properties, flexural properties and fatigue strength, whereas specific wear rate and coefficient of friction increased significantly. Reinforcing PTFE filled POM composites with 1 wt% functionalized CNTs has led to improvement of strength, stiffness, wear resistance and fatigue strength. Hybrid composites with 10 wt% PTFE and 1 wt% functionalized CNTs resulted in improvement of strength and stiffness by 31% and 50% respectively and decrease in wear rate and friction coefficient by 67% and 44% respectively as compared to pristine POM.