The Effect of Process Factors to the Kinetic Studies of Emulsion Copolymerization of Natural Rubber and Styrene

Abstract

Graft copolymer of styrene on natural rubber was prepared in laboratory by emulsion polymerization using potassium persulfate and sodium laurysulfate as an initiator and an emulsifier, respectively. The concentrations of initiator and emulsifier were varied in the range of 0.7 to 2.0 parts and 5.0 to 11.0 part per 100 parts of organic compositions, respectively. The gross polymers were purified by soxhlet extraction to remove ungrafted polystyrene and ungrafted natural rubber to obtain the graft copolymer (NR-g-PS). Characterization of graft copolymer was confirmed by FTIR spectroscopy. The results of the conversion, the kinetic rate of polymerization and grafting efficiency as a function of initiator and emulsifier concentration were studied. It was found that the conversion and the rate of polymerization increased with initiator and emulsifier concentration. At 1.0 parts of initiator and 5.0 parts of emulsifier were the optimum values. Therefore, the conversion and grafting efficiency can be used to predict the reaction conditions as a guideline for the graft copolymer production in pre-scale up reactor.