Crystallization in binary blends of polytetrafluoroethylene with perfluorinated tetrafluoroethylene copolymer

Abstract

Miscibility and crystallization were studied for two binary blends of polytetrafluoroethylene (PTFE) with poly(tetrafluoroethylene-co-10mol% hexafluoropropylene) (FEP) and poly(tetrafluoroethylene-co-2mol% perfluoropropylvinyl ether) (PFA), using DSC and X-Ray diffractometry. In FEP/PTFE blends, FEP and PTFE components were separately crystallized to form their own crystallites, while in PFA/PTFE blends, PFA and PTFE components were cocrystallized to form PTFE-type crystallites incorporating tetrafluoroethylene segments of PFA and PTFE. The crystallization behavior in both blends is discussed in terms of chemical structure, molecular weight, crystallization rate, blending method (how the two components are blended) and comonomer concentration.