Factorial experimental design for grafting of vinyl monomers onto natural rubber latex

Graft copolymerization of styrene (St) and methyl methacrylate (MMA) in the presence of natural rubber latex using cumene hydroperoxide/tetraethylenepen-tamine redox initiator system was prepared at various process variables. The synthesized graft copolymers were purified and then characterized by Fourier transformed infrared spectroscopy analysis. A full 2(4) factorial experimental design was applied to study the effect of various process variables on grafting efficiency. The following four independent variables considered to be mainly affecting the grafting efficiency were reaction temperature, rubber-to-monomer ratio, St-to-MMA ratio, and initiator amount used in the secondary polymerization. It was shown in this study that the reaction temperature significantly influenced the grafting efficiency, increasing as the temperature was increased. The amount of grafting increased with increasing rubber-to-monomer ratio and St-to-MMA ratio, whereas the amount of grafting decreased with increasing amount of initiator. (C) 2004 Wiley Periodicals, Inc.