Synthesis and kinetics of ascorbic acid initiated graft copolymerized delignified cellulosic fiber



Graft copolymerization of delignified Grewia optiva fiber with methyl methacrylate (MMA) as vinyl monomer was attempted using ascorbic acid/H2O2 as redox initiator. Different reaction conditions affecting the grafting percentage (Pg) were optimized to get the maximum Pg (32.56%) of MMA onto delignified Grewia optiva fibers. Grafted and ungrafted fibers were subsequently subjected to evaluation of physico-chemical properties such as swelling behavior and acid and alkali resistance. The rate expression for the grafting reaction (Rg = k [ASC]0.12 [H2O2]0.53 [MMA]0.05) was evaluated and a suitable mechanism for grafting was suggested. The overall activation energy of the copolymerization reaction was found as 11.97 kJ mol−1 at temperature range 25–65°C. Further, morphological and structural analysis of raw, delignified, and grafted Grewia optiva-g-poly(MMA) were studied by using Fourier-transform Infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis.The tensile properties of grafted and ungrafted fiber samples were also reported. POLYM. ENG. SCI., 55:474–484, 2015. © 2014 Society of Plastics Engineers