Solution properties of a propylene-tetrafluoroethylene copolymer

Abstract Solution properties of a propylene-tetrafluoroethylene (PTFE) copolymer were studied in a thermodynamically good solvent (tetrahydrofuran, THF) and in poor solvents (n-butyl acetate, methyl isobutyl ketone). Mark-Houwink relations were determined for the copolymer in particular solvents and unperturbed dimensions, K 0 = 1.58 × 10 −3 were established. The low values of the Mark-Houwink exponents of 0.19–0.36 in n-butyl acetate and methyl isobutyl ketone show that the molecules of the copolymer are in the mentioned solvents in a more compact configuration. A segment CH 3 CH 2 CHCH 3 CF 2 CF 2 CH 3 (the basic segment of an alternating PTFE copolymer) was studied by the semi empirical SCF method AM1. The segment was found to contain conformationally a very flexible bond which enables formation of the more compact structures.