The unusual thermal expansion behaviour of PTFE/GF composites incorporating PTFE/GF recyclate

This study examines the thermal expansion behaviour of virgin and recyclate polytetrafluoroethylene (PTFE)/glass fibre (GF) composites using two new sintering approaches - with and without pressure. In the case of composites sintered without pressure, the thermal expansion behaviour showed an unusual trace for both virgin and recycled samples. The introduction of a small amount glass fibre (<15 vol%) will increases the overall thermal expansion in the compression direction. This unusual behaviour could relate to pores entrapped and the alignment of the glass fibre in the structure.