Grafting of methyl methacrylate (MMA) onto Antheraea assama silk fiber

Graft copolymerization of methyl methacrylate (MMA) onto nonmulberry silk f iber Antheraea assama was investigated in aqueous medium using the KMnO4- o xalic acid redox system. Grafting (%) was determined as a function of the r eaction time, temperature, and monomer and initiator concentrations. The ra te of grafting increased progressively with increase of the reaction time u p to 4 h and then decreased. The extent of grafting was maximum at 55 degre esC. The extent was also dependent upon monomer and initiator concentration s up to 75.5 x 10(-2) and 6 x 10(-3) M, respectively. The grafted products were evaluated by infrared spectroscopy and their thermal decompositions we re studied by TG and DTG techniques in static air at 20 degreesC min(-1) an d 30 degreesC min(-1) in the range 30-800 degreesC. The kinetic parameters for ungrafted and grafted fibers were evaluated using the Coats and Redfern method. The grafted products were found to be thermally more stable than w ere those of the ungrafted fibers. The surface characteristics of the ungra fted and grafted fibers were evaluated by scanning electron microscopy. The water-retention values (WRVs) of the grafted fibers were in decreasing ord er with increase in the grafting (%). (C) 2001 John Wiley & Sons, Inc.