The copolymerization of VDF-TFE was carried out in aqueous medium containing a fluorosurfactant and with diisopropylperoxydicarbonate (IPP) as initiator and acetone as chain transfer agent. A series of VDF-TBE copolymers of different compositions and different molecular weight ranges have been prepared.The VDF-TFE copolymer shows good mechanical properties and thermal stability. The pyroelectric coefficient of the copolymer attained a maximum value which corresponds to the minimum melting point of the copolymer

at about 20mol% TFE content.