Emulsion copolymerization of tetrafluoroethylene and propylene with redox system containing tert‐butylperbenzoate. II. Polymerization mechanism

Abstract

AbstractEmulsion copolymerization of tetrafluoroethylene (TFE) and propylene (P) initiated by trilon‐rongalite catalytic system containing tert‐C4H9OH, initial monomer mixture, emulsifier (C7F15COONH4) concentration, and monomer mixture/water ratio on the polymerization rate (R) and molecular weight (M̄n ) was investigated. Both R and M̄n increased considerably with TFE content in monomer mixture up to 75 mol %. Alternating rubber‐like copolymers in a wide range of initial monomer mixture (from 55–85 mol %) were obtained. The reactivity ratio was found to be rTFE = 0.005 ± 0.04 and rp = 0.17 ± 0.07. Above the critical miscelle concentration, the effects of the initiating system Is and emulsifier Cs on R and M̄n were found to obey the following relations: according to which emulsion copolymerization proceeds by the I case of Smith‐Ewart theory. Polymerization mechanism of the reaction studied was suggested. The copolymerization is mainly terminated by degradative chain transfer of the propagating radicals to propylene. © 1994 John Wiley & Sons, Inc.