Equilibrium character of postradiational grafting of MMA to a tetrafluoroethylene-vinylidenefluoride copolymer

The kinetics and mechanism of postradiational graft polymerization of MMA to a copolymer of tetrafluoroethylene and vinylidene fluoride were investigated. The phenomenon of the “limitation” of polymer yield was observed at a constant concentration of monomer in the gas phase and a constant concentration of active centres as determined by the methods of EPR spectroscopy; an increase in monomer vapour pressure leads to resumption of polymerization and to the establishment of a new, higher limiting yield of polymer. By EPR spectroscopic methods with deuterium labelled MMA, the reversible character of monomer addition to the macroradicals was established under the conditions of polymer yield limitation. The specific growth rates of kinetic chains and the rate constant of depolymerization were determined from the kinetics of equilibrium establishment. The possible causes of the observed effects are discussed.