Abstract
trans-1,3,3,3-Tetrafluoropropene (1234ze) was copolymerizedunder free radical conditions with vinylidene fluoride (VDF) andtrifluoroethylene (TrFE), for the first time, leading to statisticalpoly(VDF-ter-TrFE-ter-1234ze) electroactive terpolymers. The reactivityratios of the three comonomer couples were determined (rVDF = 0.77;rTrFE = 0.32), (rVDF = 1.67; r1234ze = 0.00), and (rTrFE = 7.56; r1234ze = 0.00),at 48 °C, using the nonlinear fitting Mayo−Lewis method. 1234ze wasshown to be regularly incorporated in the terpolymer chains over theentire course of the reaction providing terpolymer chains with statisticalmonomer distribution and almost constant composition. These newVDF/TrFE-based terpolymers were characterized by 1H and 19F liquidstate NMR spectroscopy. The characteristic NMR signals of the VDF−1234ze dyads were identified by comparing the NMR spectral signaturesof a poly(VDF82-co-1234ze18) copolymer and of a terpolymer. The thermal and electroactive properties of poly(VDF-ter-TrFEter-1234ze) terpolymers, with 1234ze content ranging from 0 to 6 mol % and molar masses above 55 kg/mol, were assessed. Therandomly distributed 1234ze termonomer units induced the decreases of both the Curie and the melting temperatures of theterpolymer even at low termonomer content (TCurie = 70 °C and Tm = 126 °C and TCurie = 72 °C and Tm = 150 °C; for apoly(VDF69-ter-TrFE28-ter-1234ze3) terpolymer and a poly(VDF65-co-TrFE35) copolymer, respectively). Films of the terpolymerswere cast, and their electroactive properties were examined by D−E loops measurements. They showed that the presence of1234ze decreased the remnant polarization (Pr = 45 mC/m2 for a poly(VDF65-co-TrFE35) copolymer to 28 mC/m2 for apoly(VDF69-ter-TrFE25-ter-1234ze6) terpolymer) probably because it also decreased the crystallinity of the terpolymer. Thecombination of the studies of the reactivity of the monomers, of the terpolymer microstructures, and of the assessment of theirphysical properties provides insights into their structure−property relationship.