The aqueous radical homopolymerization of vinylidene fluoride (VDF), as well as its copolymerizations with hexafluoropropylene (HFP) or perfluoromethyl vinyl ether (PMVE), and its terpolymerization with HFP and PMVE, initiated by trifluoromethyl radicals (^•CF₃), generated from the ammonium persulfate (APS) and potassium trifluoromethyl sulfinate (CF₃SO₂K) redox system are presented. The optimization of the experimental conditions in terms of initial reactant molar ratios, temperature, and reaction time was achieved. The best results were obtained at 60 °C, in water, without any surfactant, using 0.9 equiv of APS as the oxidant with respect to CF₃SO₂K. PVDF, poly(VDF-co-HFP), poly(VDF-co-PMVE), or poly(VDF-ter-PMVE-ter-HFP) copolymers were obtained in high yields (varying between 89 and 100%) and with molar masses up to 113,000 g/mol. The ¹H and ¹⁹F NMR spectroscopies revealed that, under optimized conditions, the formed chain ends were exclusively CF₃ or CF₂H. The influence of the nature of the chain end on the thermal stability showed that PVDFs terminated by CF₃ were more stable than their analogues bearing sulfate end groups by 120 °C. In addition, the prepared CF₃-PVDFs had 53% of crystallinity (compared to 47% for PVDF initiated from APS alone), which offers excellent resistance to conventional organic solvents including dimethyl sulfoxide, acetone, and dimethyl formamide.

中文翻译：

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链端功能：影响含氟聚合物热稳定性的关键因素

偏二氟乙烯 (VDF) 的水性自由基均聚，以及它与六氟丙烯 (HFP) 或全氟甲基乙烯基醚 (PMVE) 的共聚，以及它与 HFP 和 PMVE 的三聚反应，由三氟甲基自由基 ( ^• CF ₃ ) 引发，由介绍了过硫酸铵 (APS) 和三氟甲基亚磺酸钾 (CF ₃ SO ₂ K) 氧化还原系统。在初始反应物摩尔比、温度和反应时间方面实现了实验条件的优化。最好的结果是在 60 °C 下，在水中，没有任何表面活性剂，使用 0.9 当量的 APS 作为 CF ₃ SO ₂ K的氧化剂。PVDF，聚（VDF- co-HFP)、聚 (VDF- co -PMVE) 或聚 (VDF- ter -PMVE- ter -HFP) 共聚物以高产率（在 89% 和 100% 之间变化）获得，摩尔质量高达 113,000 g/mol . 的¹ H和^19个F NMR光谱表明，优化的条件下，所形成的链端是专门CF ₃或CF ₂ H.对热稳定的链端的性质的影响表明，通过PVDFs CF终止₃更在 120 °C 时比带有硫酸盐端基的类似物稳定。此外，制备的 CF ₃-PVDF 的结晶度为 53%（相比之下，仅由 APS 引发的 PVDF 为 47%），对包括二甲基亚砜、丙酮和二甲基甲酰胺在内的常规有机溶剂具有出色的耐受性。