POLY(ACRYLIC ACID)-STARCH COMPOSITES - A KEY FOR IMPROVING SIZABILITY AND DESIZABILITY OF STARCH FROM COTTON TEXTILES

Maize and rice starches were independently polymerized with acrylic acid (AA) using potassium permanganate/citric acid initiation system. The dependence of total conversion (grafting and homopolymerization) on AA, potassium permanganate and citric acid concentrations, time and temperature of polymerization and rate of stirring were studied. Based on the results appropriate conditions for preparation of poly(AA)-starch composites were established. While the total conversion increased by increasing AA concentration from 10% to 30%. based on weight of starch (ows), maximum total conversion occured upon using 0.2% potassium permanganate along with 0.025% citric acid, ows, for 10 min at 40-degrees-C and stirring rate of 300 r.p.m. It was further disclosed that: (a) the total conversion for maize starch is higher than rice starch, (b) the apparent viscosity of the composite increases by increasing AA concentration from 10% to 30% and polymerization temperature from 30-degrees-C to 50-degrees-C, (c) for 10% AA concentration the composite consists of 97.67 starch and 2.33% poly(AA) of which 1.36% is grafted whereas for 30% AA concentration the composite consists of 79.3% starch and 20.7% poly(AA) of which 3.2% is grafted, (d) the sizeability of native starches is considerably improved after polymerization with AA and (e) size removal from cotton fabric with the composites to ca. 80% while wize removal from cotton fabric sized with native starches amounts to ca. 20%.