On the reactivity of α-trifluoromethylstyrene in radical copolymerizations with various fluoroalkenes

Abstract

The synthesis and radical co- and terpolymerizations of α-trifluoromethylstyrene (TFMST) with various fluorinated and hydrogenated comonomers are presented. The selected fluorinated comonomers were: vinylidene fluoride (VDF), chlorotrifluoroethylene (CTFE), 3,3,3-trifluoropropene (TFP), 1H,1H,2H,2H-perfluoro-1-decyl vinyl ether (FAVE-8), while the hydrogenated one was ethyl vinyl ether (EVE). Though the homopolymerization and most copolymerizations of TFMST failed, the radical terpolymerization of TFMST with VDF and CTFE led to successful reaction in ca. 40–80% yield, when the TFMST feed was lower than 9mol%. The resulting terpolymers were characterized by 1H and 19F NMR spectroscopy that enabled to assess the molar percentages of the three comonomer units and revealed VDF-TFMST and CTFE-TFMST dyads besides expected VDF-VDF, VDF-CTFE, CTFE-CTFE dyads, and various triads composed of these monomers. Molecular weights were in the range of 2000–5000gmol−1 indicating that oligomers were obtained. TGA under air indicated that poly(CTFE-ter-VDF-ter-TFMST) terpolymers do not degrade below 150°C, while DSC experiments confirmed the terpolymer structure as only a single glass transition temperature at about −35°C.