Yogesh Patil, Ono Taizo, Bruno Ameduri
Institut Charles Gerhardt, Ingénierie et Architectures Macromoléculaires, UMR 5253, Ecole Nationale Supérieure de Chimie de Montpellier, 8, rue de l'Ecole Normale F-34296 Montpellier, France.
National Institute of Advanced Industrial Science and Technology, Research Institute of Instrumentation Frontier, 2266-98, Anagahora, Shimoshidami, Moriyama, Nagoya, Aichi, 463-8560, Japan.
ACS Macro Lett. 2012 Feb 21;1(2):315-320. doi: 10.1021/mz200202a. Epub 2012 Jan 26.
A persistent perfluoroalkyl branched radical (PPFR), perfluoro-3-ethyl-2,4-dimethyl-3-pentyl, was shown to be a good source of CF radicals able to initiate the radical copolymerization of vinylidene fluoride (VDF) with -butyl α-trifluoromethacrylate (MAF-TBE). NMR characterizations of the resulting poly(VDF--MAF-TBE) copolymers showed that copolymerization was exclusively initiated by CF radicals, as evidenced by the thermal decomposition of PPFR above 80 °C. The addition of CF radical onto VDF/MAF-TBE system was regioselective leading to CF-CH-CF radical that further cross propagated onto MAF-TBE unit and the α,ω-trifluoromethyl group acted as an efficient label to assess the molecular weights of the resulting copolymers by F NMR spectroscopy. Three [PPFR]/([VDF] + [MAF-TBE]) initial molar ratios (2.0, 1.0, and 0.5%) led to various molecular weights ranging from 21300 to about 105000 g·mol. When that ratio decreased, both the molecular weights and the thermostability of these original poly(VDF--MAF-TBE) copolymers increased.
一种持久性全氟烷基支链自由基（PPFR），即全氟-3-乙基-2,4-二甲基-3-戊基自由基，被证明是能够引发偏二氟乙烯（VDF）与α-三氟甲基丙烯酸叔丁酯（MAF-TBE）进行自由基共聚反应的CF自由基的良好来源。对所得聚（VDF-MAF-TBE）共聚物的核磁共振表征表明，共聚反应完全由CF自由基引发，这一点在80℃以上PPFR的热分解中得到了证实。CF自由基加成到VDF/MAF-TBE体系上具有区域选择性，生成CF-CH-CF自由基，该自由基进一步与MAF-TBE单元交叉增长，并且α,ω-三氟甲基基团作为一种有效的标记，通过氟核磁共振光谱来评估所得共聚物的分子量。三种[PPFR]/（[VDF]+[MAF-TBE]）初始摩尔比（2.0%、1.0%和0.5%）导致了分子量在21300至约105000 g·mol之间变化。当该比例降低时，这些原始聚（VDF-MAF-TBE）共聚物的分子量和热稳定性均增加。
