Dielectric properties of block copolymers based on vinylidene fluoride and cyano comonomers
Résumé
The synthesis of poly(vinylidene fluoride)-b-poly(AN, MAN, VCN) (PVDF-b-MCN) block copolymers, using the iodine transfer polymerization (ITP) of vinylidene cyanide, acrylonitrile and méthacrylonitrile, in the presence of PVDF-I, are presented. In a first step, the ITP of vinylidene fluoride in the presence of C6F13I as the chain transfer agents leads to two different isomeric oligomers (PVDF-I), bearing either -CH2I or –CF2I end-groups. The ITP of cyanide monomers (MCN) using those latter fluorinated oligomers as macromolecular chain transfer agents, were achieved as shown in scheme below. The characterization of sampled aliquots by 19F and 1H NMR spectroscopy could monitor the average degree of polymerization in number versus cyanide monomers conversions. ITP of cyanide monomers. These block copolymers were characterized by 19F and 1H NMR and by SEC chromatography. Their thermal properties were also studied by differential scanning calorimetry (DSC), respectively.