Process Parameters and Their Effect on Grafting Efficiency and Degree of Grafting in Styrene-Acrylonitrile-graft Polybutadiene (g-ABS) Using Seeded Emulsion Polymerization

Graft copolymers of acrylonitrile (AN) styrene (SM) onto polybutadiene (PB) were prepared via seeded emulsion polymerization method using a redox initiator system, cumene hydroperoxide-tetrasodium pyrophosphate-ferrous sulfate-dextrose. The effects of initiator, chain transfer agent, reaction temperature, monomer dropping frequency, polymer to grafting monomer ratio on the grafting efficiency and degree of grafting were investigated. It was found that grafting efficiency and degree of grafting depended upon the concentration and initiator dropping frequency; it increased as the concentration and dropping time were increased. The grafting efficiency and degree of grafting increased by increasing monomer dropping frequency. The amount of free SAN was found to decrease concurrently by increasing monomer dropping time. The optimum temperature and monomer addition time for grafting reaction were 70°C and 120 minutes respectively.