[Bill Edgeworth]

In the world of plastics fluoropolymers (Teflon) has a middle of the road thermal conductance. It is an excellent high temperature service plastic however wood only has about ½ the thermal conductivity of PTFE. But comparing Teflon to aluminum Teflon is 1000 times less thermal conductive.
Cork has about ½ the thermal conductance of wood or ¼ that of Teflon.
So, technically a paper or cork gasket is going to give you far better insulating properties than a Teflon one of the same thickness. Or in the case of thermal spacers wood or paper fiber insulate 2x better than Teflon or nylon.