Radical copolymerization of α-trifluoromethylacrylic acid with vinylidene fluoride and vinylidene fluoride/hexafluoropropene

Abstract

The radical copolymerization of α-trifluoromethylacrylic acid (TFMAA) with vinylidene fluoride (VDF), initiated by tert-butyl 2,2-dimethyl peroxypropanoate (or tert-butyl peroxypivalate) is presented. The kinetics of copolymerization were investigated from a series of eight reactions for which the initial [VDF]0/[TFMAA]0 molar ratios ranged between 15.0/85.0 and 89.4/10.6. The compositions of the copolymers, i.e. the molar ratios of VDF and TFMAA monomeric units, were determined mainly by 19F and 1H NMR spectroscopy. According to the Tidwell and Mortimer method, the reactivity ratios, ri, were assessed to be: rVDF = 0.33 ± 0.09 and rTFMAA 0 at 55 °C, leading to copolymers of mainly alternating structure. Then, the radical terpolymerization of TFMAA with VDF and hexafluoropropene (HFP), initiated by 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane is described and the thermal properties of the materials produced are discussed.