FACTORS INFLUENCING VAPOR-PHASE PHOTOGRAFTING OF STYRENE ACRYLONITRILE MONOMER MIXTURES ON POLYMER-FILMS

An accelerating effect due to a styrene (St)/acrylonitrile (AN) monomer mixture was investigated in vapor-phase photografting on polymer films, on which a photoinitiator was coated. A maximum percent grafting was observed at a certain St concentration of monomer feed irrespective of the nature of photoinitiator, such as benzoyl peroxide, benzophenone, and alpha,alpha'-azobisisobutylonitrile, and the type of polymer film, such as low- and high-density polyethylene, polypropyrene, and nylon 6. The same effect due to the monomer mixture was recorded for liquid-phase photografting in a water-ethanol mixture solvent. With photoinduced copolymerization of the St/AN mixture using benzoyl peroxide, conversion of AN was sharply reduced by the addition of St to the AN system using DMF, DMSO, methanol, and ethyl acetate solvents. In case of saturated hydrocarbon solvents such as n-hexane, cyclohexane, n-octane, and n-decane, on the other hand, a maximum conversion was observed at a certain St concentration of monomer feed. The accelerating, effect due to the St/AN mixture was discussed in terms of copolymerizability of monomers and a gel effect.