Duc Michel, Boutevin Bernard, Ameduri Bruno
Université de Montpellier, CNRS, ENSCM, 34000 Montpellier, France.
Molecules. 2021 May 21;26(11):3082. doi: 10.3390/molecules26113082.
The radical telomerisation of vinylidene fluoride (VDF) with 2-mercaptoethanol as chain transfer agent (CTA) was studied to synthesise fluorinated telomers which bear a hydroxy end-group, such as H(VDF)S(CH)OH, under thermal (di--butyl peroxide as the initiator) or photochemical initiations. A careful structural study of a typical H-VDF-S(CH)OH telomer was performed by H and F NMR spectroscopy. These analytical methods allowed us to explore the selective addition of the thiyl radical onto the hydrogenated side of VDF, and the telomer containing one VDF unit was obtained selectively. Surprisingly, for higher [VDF] initial concentrations, a monoadduct telomer was produced as well as PVDF homopolymer. This feature was related to the fast consumption of the CTA. The kinetics of radical telomerisation led to a quite high transfer constant of the CTA (40 at 140 °C) that evidences the formation of a monoadduct as the only telomer formed.
研究了以2-巯基乙醇作为链转移剂（CTA）对偏二氟乙烯（VDF）进行自由基调聚反应，以合成带有羟基端基的氟化调聚物，如H(VDF)S(CH)OH，反应在热引发（以过氧化二丁基作为引发剂）或光化学引发条件下进行。通过氢谱和氟谱对典型的H-VDF-S(CH)OH调聚物进行了详细的结构研究。这些分析方法使我们能够探究硫自由基在VDF氢化侧的选择性加成，并且选择性地获得了含有一个VDF单元的调聚物。令人惊讶的是，对于较高的[VDF]初始浓度，除了聚偏二氟乙烯（PVDF）均聚物外，还生成了单加成调聚物。这一特征与CTA的快速消耗有关。自由基调聚反应动力学导致CTA具有相当高的转移常数（140℃下为40），这证明了单加成产物是唯一形成的调聚物。
