Functionalization of poly(propylene) fabric with 4-vinylpyridine, N,N-dimethylacrylamide and styrene by γ-radiation-induced grafting in an aqueous environment

VP and co-monomers DMAAm and ST were successfully grafted onto a PP fabric in an emulsion copolymerization process initiated by T-radiation. The radiation dose, concentration of VP, the ratio of VP/DMAAm and VP/ST in the reaction solution, and the reaction temperature dependent graft copolymerization were investigated. The order of dependence of the initial rate of grafting on the radiation dose I was found to be in the range of 1.2 to 0.93 for VP; 0.84 to 0.70 for VP/DMAAm and for VP/ST was in the range of 0.59 to 0.41. The activation energy of the graft copolymer reaction was determined to be 40.18 J (.) mol(-1) for 0.464 mol (.) L-1 VP. In the case of co-monomer mixtures (VP/DMAAm: 0.464/0.5) the energy of activation was noticeably higher at 49.71 J (.) mol(-1) while for VP/ST (0.464/0.436) the activation energy was same as that of VP. XRD results showed that overall crystallinity significantly decreased with the increase of graft weight with a noticeable change in the chemical structure of the PP, indicating that the graft copolymer reaction was taking place both in the I amorphous and crystalline regions of PP. A similar characteristic behavior was also obtained by DSC, which revealed the presenence of an endotherm process in the range of 25 to 130 degrees C depending on the degree of grafting, attributed to the grafted chains of the monomer/co-monomers. In order to determine the graft copolymer reaction of VP, DMAAm and ST onto the backbone of PP, the reaction products were characterized by FTIR spectroscopy. A good correlation was found between changes of crystallinity and level of graft copolymerization as determined by WAXRD and DSC.