Aspects of thermal graft copolymerization of methyl methacrylate onto ethyl cellulose in homogeneous media

Abstract

Homogeneous graft copolymerization of methyl methacrylate onto ethyl cellulose using radical initiators such as ammonium persulphate, potassium persulphate and benzoyl peroxide was carried out in benzene/dimethylsulphoxide (1/1 v/v) mixed solvent system. The grafting yield was determined as functions of the polymerization temperature and the concentrations of monomer, ethyl cellulose and initiator. Different techniques were used for confirming the presence of polymethyl methacrylate grafted chains such as IR, TLC and NMR. The efficiency of grafting methyl methacrylate onto ethyl cellulose with ammonium persulphate and potassium persulphate was studied in different solvent systems. The power of solvents for increasing the grafting yield was found as follows: chloroform > toluene > benzene. The highest overall rates for copolymerization of methyl methacrylate onto ethyl cellulose using ammonium persulphate and potassium persulphate initiators were determined as 0.2% min −1 and 0.08% min −1, respectively. Benzoyl peroxide was found to be an unsuitable initiator for grafting methyl methacrylate onto ethyl cellulose. A Trommsdorf effect was observed in certain systems. The mechanism of grafting reaction of methyl methacrylate onto ethyl cellulose is discussed.