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

Abstract

Miscibility and crystallization behavior have been studied for polytetrafluoroethylene(PTFE)/poly(tetrafluoroethylene-co-2 mol-% perfluoropropylvinyl ether)(PFA copolymer) blends by the use of differential scanning calorimetry, electron microscopy, X-ray diffractometry and dynamic mechanical spectroscopy. 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 ≤ 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 of the amorphous state described above. It was conjectured that the crystallization is controlled by the PTFE matrix when the PFA content is ≤ 50 wt.-%, while by the PFA matrix when the PFA content is >50 wt.-%.