Radical and radiation‐induced grafting of some synthetic high polymers within the temperature range of their glass transition

Abstract

Abstract The temperature dependence of radiation‐induced grafting onto poly(ethylene terephthalate), polyamides, polyacrylonitrile, and polypropylene has been investigated for several monomers. In all cases a maximum grafting yield is obtained when the reaction is performed in the temperature range of the glass transition T g of the polymer used. This maximum yield does not only appear with radiation‐induced simultaneous grafting. It also appears when the graft polymerization is induced by pre‐irradiation or even by thermal decomposition of organic peroxides. It is assumed that the pronounced maximum of the reactivity at T g is obtained because in the glassy state below T g the radicals formed cannot react due to a reduced diffusion of the monomer, whereas above T g the number of radicals available for polymerization will be reduced with increasing temperature.