GRAFT COPOLYMERIZATION OF METHYL METHACRYLATE (MMA) ONTO CELLULOSE ACETATE IN HOMOGENEOUS MEDIUM: EFFECT OF SOLVENT, INITIATOR AND HOMOPOLYMER INHIBITOR

摘要

Cellulose acetate-g-polymethyl methacrylate (CA-g-PMMA) copolymer was synthesized in homogeneous medium, taking dimethyl sulfoxide (DMSO), 1,4-dioxane, N,N-dimethyl acetamide (DMAc) and acetone as solvents and ceric ammonium nitrate (CAN), benzoyl peroxide (BPO) and tin(II) 2-ethyl hexanoate [Sn(Oct)2] as initiator. The effects of solvents and initiators on graft yield (GY) and grafting efficiency (GE) were studied. The viscosity average molecular weight of grafted PMMA was calculated. The role of methylene blue (MB) as a homopolymer inhibitor and its effect on grafting was also studied. In the presence of MB the molecular weight of the grafted PMMA reduced and consequently grafting efficiency and the number of grafts per polymer chain increased. The products were characterized by FTIR and ~1H-NMR analyses and possible reaction mechanisms for different initiators were deduced. The thermal degradation of the grafted products was also studied by thermogravimetric analysis (TG) and differential thermogravimetry (DTG).