Synthesis and Characterization of Polypropylene-Grafted Gelatin

Modification of polypropylene (PP) has been successfully carried out by graft copolymerization of gelatin, by chemical method using benzoyl peroxide (BPO) as radical initiator. PP was preirradiated by gamma rays at a constant dose rate of 3.40 kGy/h before grafting to introduce hydroperoxide groups. Optimum conditions pertaining to maximum percentage of grafting were evaluated as a function of different reaction parameters. Maximum percentage of grafting of gelatin (115%) was obtained at BPO concentration = 4.132 x 10(-2) mol/L in 120 min at 70 degrees C using 30 mL of water. Characterization of PP-g-gelatin was carried out through FTIR, thermogravimetric analysis, and scanning electron microscopy. Swelling studies were carried out in pure, binary, ternary, and quaternary solvent systems comprising distilled water, ethanol, dimethylsulphoxide (DMSO), and N,N-dimethyl-formamide (DMF) in different ratios. Maximum swelling of PP-g-gelatin (both composite and true graft) was observed in pure solvents that is, DMSO followed by DMF, ethanol, and water and was higher than that observed in the mixed solvent system. Water retention studies of unmodified PP, that is, pristine PP and PP-g-gelatin (both composite and true graft) were investigated at different time periods, temperatures and pH. Maximum water retention for PP-g-gelatin (composite; 170%) was observed in 8 h at 50 degrees C in neutral medium (pH = 7). (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 1226-1236, 2010