text: difference between cast polyurethane and cast teflon?? we are looking at casting both the compounds so i need to know the diff in physical & chemical properties with respect to application in automobile field. polyethylene (pe) and teflon (ptfe) are very different plastics, with very different physical properties.  also, there are many varieties of both polymers depending on the molecular weight.  higher weight generally equals better mechanical properties.  if you're looking for something with good wear and thermal resistance - that's ptfe.  on the other hand, pe tends to be more tough.  pe is a lot cheaper too.