Unexpected Radical Telomerisation of Vinylidene Fluoride with 2-Mercaptoethanol

Abstract

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)nS(CH2)2OH, under thermal (di-tert-butyl peroxide as the initiator) or photochemical initiations. A careful structural study of a typical H-VDF-S(CH2)2OH telomer was performed by 1H and 19F 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]o 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.

Radiation Curing of Phosphorus Telomer-Based Coatings Using UV LEDs or Medium-Pressure Mercury Lamp

“…However, a less frequently described method of preparation for copolymers with controlled structures is telomerization-a special type of polymerization consisting of a chain reaction between a telogen (also called a chain transfer agent, a molecule with easily radically cleavable bonds, e.g., P-H, C-Br, S-H) and one or more polymerizable compounds (taxogens/monomers, exhibiting ethylenic unsaturation), which leads to the synthesis of low-molecular-weight oligomers with terminal groups derived from telogen [28,29]. Regarding the synthesis of phosphorus-containing oligomers by telomerization, dialkyl phosphites, phosphorus acid, phosphorus tri-and pentachloride, and alkyl dichlorophosphines or dichlorophosphonates are typically used as telogens.…”