Friction coefficient from side chains

The two most often used fillers in thermoplastics are PTFE and PDMS or silicone. The respective functions of the two materials are quite different. PTFE is almost the wonder additive for tribological applications, whether in a solid polymer or liquid lubricant. The mechaiucal properties of PTFE hold over a range of -260°C to 260°C with a melt temperature of 321°C. It is chanicaUy inert and hydrophobic. The effect of PTFE as a solid lubricant can be understood from its performance as a homopolymer. As a homopolymer, PTFE has the lowest coefficient of friction of all polymeric materials sliding against metal surfaces. This is due to the lack of bulky side groups on the molecular chain and the formation of a low friction transfer film on the opposing counterface. However, due to the poor mechanical properties, PTFE alone also... 

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