Studies on Wear Properties of Polystyrene in the Presence of Fibrillated Network of Polytetrafluoroethylene

Abstract

Polystyrene (PS) is an important commodity plastic; however, it is not known as a suitable material for tribological applications. It has a relatively high friction coefficient in contact with metallic surfaces and high abrasion loss factor. Polytetrafluoroethylene (PTFE) is a known friction modifier, has a low friction coefficient, and is extensively used to reduce the friction coefficient and wear rate (with engineering plastics to improve tribological properties). It is known for fluoroelastomers and engineering plastics that fine particles of PTFE have the greatest effect on improving the specified properties. Here, oriented, fibrillated network morphology of PTFE in PS matrix was prepared. The wear studies show a large reduction in both the friction coefficient (45% reduction) and the wear rate (2% incorporation of PTFE leads to a 49% reduction). But the friction coefficients do not show any significant change on increasing PTFE. A similar observation was made for the wear rate. Scanning electron microscope (SEM) images of the worn surfaces show a crack tip bridging mechanism, and it was observed that with the increase in PTFE content, the extent of crack tip bridging increases. This extensive improvement may be attributed to the unique morphology of the blend system.