Preparation and properties of surface-modified tungsten trioxide-filled polytetrafluoroethylene composites
To improve the wear resistance of polytetrafluoroethylene(PTFE),KH560-surface-modified and non-surface-modified tungsten trioxide(WO3)filled polytetrafluoroethylene composites were comparatively studied.The PTFE/na-no-WO3 composites were prepared through cold pressing and sintering,and their mechanical and tribological properties were investigated by using material testing and wear testing machines.The effects of nano-WO3 content and surface mod-ification on the properties of the composites were also investigated.The results indicated that grafting KH560 on the sur-face of nano-WO3 improved the compatibility between the PTFE matrix and modified nano-WO3 and thus improved the mechanical properties of the PTFE/nano-WO3 composites.Compared to pure PTFE,the composite containing 5 wt%modified nano-WO3 showed a decrease in tensile strength by 17.7%,but an increase in elongation at break increased by 43.5%and in bending strength by 16.1%.Compared to the composites with unmodified nano-WO3,the introduction of modified nano-WO3 effectively improved the wear resistance of PTFE.The friction coefficient and wear rate of the composite containing 5 wt%modified nano-WO3 were reduced by 14.2%and 73.4%,respectively,compared to those of pure PTFE.The findings of this work will provide a technical reference for the application of PTFE and the research and development of new materials.