Radical telomerisation of vinylidene fluoride with diethyl hydrogenphosphonate: Characterisation of the first telomeric adducts and assessment of the transfer constants

The radical telomerisation of vinylidene fluoride (VDF) with diethyl hydrogenphosphonate (DEHP) was investigated to synthesize fluorinated telomers bearing a phosphonate end-group, as H(VDF)nP(O)(OEt)2. Di-t-butyl peroxide was the most effective radical initiator A minute structural study of typical VDF–DEHP telomers was performed by 1H, 13C, 19F, 31P NMR spectroscopies. These analytical methods allowed us to prove the selective addition of the phosphonyl radical onto the hydrogenated side of VDF, while the telomers containing more than two VDF units were composed of isomers. The kinetics of telomerisation led to the assessment of the six first order transfer constants giving an infinite transfer constant of 0.38 at 140°C for DEHP.