Synthesis and polymerization of fluorinated monomers bearing a reactive lateral group 13. Copolymerization of vinylidene fluoride with 2-benzoyloxypentafluoropropene

Abstract

The synthesis of 2-benzoyloxypentafluoropropene (BPFP) and its radical copolymerization with vinylidene fluoride (VDF), initiated by tert-butyl peroxypivalate is presented. In a first step, the preparation of two monomers [F 2CC(CF 3)OCOR were R stands for CH 3 or C 6H 5] was attempted. In contrast to the acetoxy derivative that could not be isolated, the benzoyl monomer was purified and then copolymerized with VDF. A series of 11 copolymerization reactions was achieved starting from initial [VDF] 0/([BPFP] 0+[VDF] 0) molar ratios ranging from 19 to 99 mol%. The molar compositions of the obtained copolymers were assessed by means of 19F nuclear magnetic resonance spectroscopy. From the Tidwell and Mortimer method, this kinetics of copolymerization led to the determination of the reactivity ratios, r i , of both comonomers ( r VDF=0.77±0.40 and r BPFP=0.11±0.32). Hence, the Alfrey and Price equation enabled one to assess the Q and e parameters of BPFP as follows: 0.019 (from Q VDF=0.008), 0.043 (from Q VDF=0.015) or 0.182 (from Q VDF=0.036) and 1.97 (vs e VDF=0.40), 2.07 (vs e VDF=0.50) or 2.77 (vs e VDF=1.20), respectively. These Q– e parameters and r i were compared to those of other fluoroalkenes and are discussed.