Synthesis and characterization of poly(acrylic acid) and poly(glycidyl methacrylate) chitosan graft copolymers and their application to cotton fabric

Graft polymerization of acrylic acid (AA) and glycidyl methacrylate (GMA) onto chitosan was independently effected in a homogeneous aqueous phase under different conditions by using potassium bromate/thiourea as a combined redox system. The grafting reaction was monitored for carboxyl and epoxy groups in the case of AA and GMA, respectively. Also monitored were percentages of graft yield (GY%), homopolymer (HP%), and total conversion (TC%). It was found that the extent of the grafting reaction, as measured by such analyses, are dependent upon monomer concentration, initiator concentration, reaction time, temperature, and material-to-liquor ratio. Based on the results obtained, the most appropriate conditions for graft copolymerization of AA onto chitosan were 4/4mmole/L thiourea/potassium bromate and AA 30% based on weight of chitosan at 40 degrees C for 1 hour. On the other hand, graft copolymerization of GMA occurs effectively when 6/6 mmole/L thiourea/potassium bromate and GMA 50% were used at 60 degrees C for 1 hour. With both AA and GMA monomers, a material-to-liquor ratio of 1:25 was adequate. Chitosan-g-poly (AA) and chitosan-g-poly (GMA) were applied to cotton fabric to enhance the easy care properties. Crease recovery angle increased from 115 degrees to 160 degrees in the dry state and from 113 degrees to 230 degrees in the wet state; meanwhile, tensile strength increased from 54 Kg to 66 Kg. Dyeability, expressed as K/S, of cotton fabric treated with these copolymers also increased.