Ferrous-persulphate Induced Graft Copolymerization of Monomer Mixtures onto Saccharum spontaneum-L Natural Fibre

Grafting of binary vinyl monomer mixtures such as methylmethacrylate (MMA) + acrylamide (AAm), MMA + acrylonitrile (AN) and MMA + acrylic acid (AA) onto Saccharum spontaneum-L (Ss) fibre, was carried out in air. The synthesized graft copolymers were characterized with FTIR spectroscopy, scanning electron microscopy (SEM), TGA/DTA/DTG and X-ray diffraction (XRD) techniques. Initial optimization of different reaction parameters was carried out for graft copolymerization of MMA onto fibre backbone. The different optimized parameters were: reaction time, 180 min; temperature, 40؛C; pH 6; solvent, 125 mL; FAS/KPS (0.225/0.112 g/g) 1/0.75 and MMA, 2.94x10-3 mol/L. The optimum graft yield with MMA was found to be 144.4%. Maximum graft yield was found to be 155.6%, 161.4% and 173.5% with MMA + AA, MMA + AN and MMA + AAm, respectively. On thermal analysis, the rate of weight loss per minute was found minimum in case of Ss-g-poly(MMA+AAm) followed by the weight losses for Ss-g-poly(MMA+AN), Ss-g-poly(MMA+AA) and S. spontaneum-L fibres. Thermal stability of Ss-g-poly(MMA+AAm) was found to be more than that of S. spontaneum-L fibre and other graft copolymers. On grafting, the crystalline lattice of the fibre was disturbed due to incorporation of homopolymer chains onto fibres back bone. Graft copolymers were found to possess lower percentage of crystallinity and crystallinity index. It was observed that graft copolymers were more resistant towards 5N HCl and 5N NaOH as compared to original fibres backbone. The graft copolymer of MMA + AN with S. spontaneum-L fibre was found to be more moisture resistant than the other aformentioned graft copolymers.