Influence of trans-1,3,3,3-Tetrafluoropropene on the Structure–Properties Relationship of VDF- and TrFE-Based Terpolymers

详细信息    查看全文

• 作者：Thibaut Soulestin ; Pedro Marcelino Dos Santos Filho ; Vincent Ladmiral ; Cedric Totée ; Gilles Silly ; Thierry Lannuzel ; Fabrice Domingues Dos Santos ; Bruno Ameduri
• 刊名：Macromolecules
• 出版年：2017
• 出版时间：January 24, 2017
• 年：2017
• 卷：50
• 期：2
• 页码：503-514
• 全文大小：621K
• ISSN：1520-5835

文摘

trans-1,3,3,3-Tetrafluoropropene (1234ze) was copolymerized under free radical conditions with vinylidene fluoride (VDF) and trifluoroethylene (TrFE), for the first time, leading to statistical poly(VDF-ter-TrFE-ter-1234ze) electroactive terpolymers. The reactivity ratios of the three comonomer couples were determined (r_VDF = 0.77; r_TrFE = 0.32), (r_VDF = 1.67; r_1234ze = 0.00), and (r_TrFE = 7.56; r_1234ze = 0.00), at 48 °C, using the nonlinear fitting Mayo–Lewis method. 1234ze was shown to be regularly incorporated in the terpolymer chains over the entire course of the reaction providing terpolymer chains with statistical monomer distribution and almost constant composition. These new VDF/TrFE-based terpolymers were characterized by ¹H and ¹⁹F liquid state NMR spectroscopy. The characteristic NMR signals of the VDF–1234ze dyads were identified by comparing the NMR spectral signatures of a poly(VDF₈₂-co-1234ze₁₈) copolymer and of a terpolymer. The thermal and electroactive properties of poly(VDF-ter-TrFE-ter-1234ze) terpolymers, with 1234ze content ranging from 0 to 6 mol % and molar masses above 55 kg/mol, were assessed. The randomly distributed 1234ze termonomer units induced the decreases of both the Curie and the melting temperatures of the terpolymer even at low termonomer content (T_Curie = 70 °C and T_m = 126 °C and T_Curie = 72 °C and T_m = 150 °C; for a poly(VDF₆₉-ter-TrFE₂₈-ter-1234ze₃) terpolymer and a poly(VDF₆₅-co-TrFE₃₅) copolymer, respectively). Films of the terpolymers were cast, and their electroactive properties were examined by D–E loops measurements. They showed that the presence of 1234ze decreased the remnant polarization (P_r = 45 mC/m² for a poly(VDF₆₅-co-TrFE₃₅) copolymer to 28 mC/m² for a poly(VDF₆₉-ter-TrFE₂₅-ter-1234ze₆) terpolymer) probably because it also decreased the crystallinity of the terpolymer. The combination of the studies of the reactivity of the monomers, of the terpolymer microstructures, and of the assessment of their physical properties provides insights into their structure–property relationship.