Radiation grafting polymerization of N,N-dimethyl acrylamide on polypropylene

The radiation grafting of N,N-dimethlacrylamide (DMAA) on polypropylene (PP) films was investigated by the following three methods. In the mutual grafting, the effect of solvents on the grafting was notable. The grafting did not occur in the aqueous solution of DMAA due to the formation of insoluble homopolymers. The suitable solvent for the grafting was benzene. The maximum grafting occurred in 45 - 65% monomer concentration. In the grafting on peroxidized PP, the effect of solvents on the grafting was notable. The grafting did not occur in the aqueous solution of DMAA due to the formation of insoluble homopolymers. The suitable solvent for the grafting was benzene. The extent of grafting increased with increasing DMAA content. The graft polymerization was induced above 50 deg C, and increased with the rist of reaction temperature. In the grafting by trapped radicals, the graft polymerization was induced even at 0 deg C. The conversion of DMAA homopolymer was very small, and the extent of grafting was larger than that obtained by two methods mentioned above. The PP films on which more than 500 % of DMAA was grafted were easily obtained. It is important for the grafting to suppress the formation of DMAA homopolymer outside PP films, and to diffuse monomer into PP films. The graft polymerization was induced only in the amorphous region of PP films. (Kako, I.)