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 hydrog enphosphonate (DEHP) was investigated to synthesize fluorinated telomers be aring a phosphonate end-group, as H(VDF)(n)P(O)(OEt)(2). Di-t-butyl peroxid e was the most effective radical initiator A minute structural study of typ ical VDF-DEHP telomers was performed by H-1, C-13, F-19, P-31 NMR spectrosc opies. These analytical methods allowed us to prove the selective addition of the phosphonyl radical onto the hydrogenated side of VDF, while the telo mers containing more than two VDF units were composed of isomers. The kinet ics of telomerisation led to the assessment of the six first order transfer constants giving an infinite transfer constant of 0.38 at 140 degreesC for DEHP. (C) 2001 Elsevier Science B.V. All rights reserved.