Grafting of polymethyl methacrylate onto cellulose acetate in homogeneous medium using ceric (IV) ion as initiator

Abstract

CA-g-PMMA copolymer has been synthesized in homogeneous medium of dimethyl sulfoxide (DMSO) using ceric ammonium nitrate (CAN) as initiator. Different grafting parameters, such as graft yield, grafting efficiency and total conversion of monomer to polymer are evaluated at different reaction conditions of temperature, time, monomer and initiator concentrations. It is observed that the graft yield decreases with increase in temperature of grafting. CAN in presence of DMSO forms free radical on cellulose acetate (CA) backbone via ring opening mechanism and polymethyl methacrylate (PMMA) is grafted through homogeneous breaking of the acrylic double bond. The role of methylene blue (MB) as a homopolymer inhibitor and its effect on grafting is also studied. In presence of MB the amount of PMMA homopolymer formation reduces and consequently graft yield increases. The viscosity average molecular weights of grafted PMMA and rate of grafting are also calculated. The products are characterized by FTIR and ¹H-NMR analyses and a possible reaction mechanism is deduced. The thermal degradation of the grafted products is also studied by thermogravimetric analysis and differential thermogravimetry.