Miscibility and crystallization of polytetrafluoroethylene/poly(tetrafluoroethylene-co-perfluoropropylvinyl ether) blends

Miscibility and crystallization behavior have been studied for polytetraflu oroethylene(PTFE)/ poly(tetrafluoroethylene-co-2 mol-% perfluoropropylvinyl ether)(PFA copolymer) blends by the use of differential scanning calorimet ry, electron microscopy, X-ray diffractometry and dynamic mechanical spectr oscopy. In the amorphous phase, the two components were miscible with each other over all blending ratios, and it was found that the PFA copolymer was compatible with the PTFE matrix. when the PFA content is less than or equa l to 50 wt.-%, while PTFE was mixed in the PFA matrix when the PFA content is >50 wt.-%. All the blends were crystalline as well as PTFE and PFA. The crystallization behavior was closely connected to the polymer composition o f the amorphous state described above. It was conjectured that the crystall ization is controlled by the PTFE matrix when the PFA content is less than or equal to 50 wt.-%, while by the PFA matrix when the PFA content is >50 w t.-%.