Mechanical Properties of Graft Copolymers of Methyl Methacrylate and Modified Wool

Abstract

Graft copolymerization of methyl methacrylate was performed onto wool chemically modified with caustic soda, formic acid, thioglycollic acid, and sodium bisulfite using ferrous ion-hydrogen peroxide redox system at 45°C. The percent graft-on was found to be higher in modified fibers. The graft-on increases with reaction time up to about 10 hr. Some mechanical properties of such graft copolymers were studied. With polymer formation, the strength decreases a little, probably due to the initiator free radicals; the breaking elongation falls considerably, particularly in reduced fibers. The Young's static modulus decreases after acid and alkali treatment and increases after reduction. The modulus is found to decrease slightly with graft-on in normal, alkali-treated and formic acid-treated wool. However, in case of reduced wool, an initial increase of modulus with polymer uptake is followed by a decrease.