Effects of water solubility of acrylonitrile on vinylidene chloride/acrylonitrile/styrene suspension polymerization

The water solubility of acrylonitrile (AN) and its effects on vinylidene ch loride/acrylonitrile/styrene (VDC/AN/St) suspension copolymerization were i nvestigated in this study. It shows that the VDC/St ratio and the presence of suspending agent have no obvious influences on AN phase partition betwee n the monomer and aqueous phases, whereas the water solubility of AN increa ses as temperature increases. Polymerization in the aqueous phase occurs ex tensively with azobis(isobutyronitrile) (AIBN) as initiator, whereas with l auryl peroxide (LPO) as initiator, polymerization in the aqueous phase is n egligible. Theoretical analysis and experimental results indicate that tran sport of the monomer molecule is possible during polymerization. Both VDC a nd AN transfer from the monomer phase to the aqueous phase when AIBN is use d as initiator. AN transfers from the aqueous phase to the monomer phase fo r the polymerization system initiated by LPO. Sodium nitrite (NaNO2), but n ot sodium sulfide (Na2S), can be used to effectively inhibit polymerization in water and exerts less influence on the polymerization in the monomer ph ase. (C) 2000 John Wiley & Sons, Inc.