Effects of initiator on the morphology and compatibility of components of poly(methyl methacrylate)/polystyrene composite latex and polymer blends

In this study, the poly(methyl methacrylate) I polystyrene (PMMA/PS) composite latex was synthesized by soapless seeded emulsion polymerization in two steps. In the first step reaction, potassium persulfate (K2S2O8) was used as initiator to synthesize the PMMA seed latex. In the second step reaction, potassium persulfate, 4,4'-azobis(4-cyanovaleric acid) (ABCVA) and azobis(isobutyronitrile) (AIBN) was used as initiator respectively to synthesize polystyrene in the presence of PMMA seed latex to form three PMMA/PS composite latexes with different morphology. The morphology of the PMMA/PS composite polymer latex could be controlled by the initiator in the second step reaction. The three composite polymer latexes were analyzed by TLC-FID. The results showed that there were PMMA-graft-PS copolymer consisted in the PMMA/PS composite polymer latex. The amount of PMMA-graft-PS copolymer was influenced by the initiator used in the second stage reaction. The compatibility of PMMA phase and PS phase in the composite polymer latex was influenced by the amount of PMMA-graft -PS copolymer. The effects of thermal annealing on the morphology of composite polymer latex were investigated. PMMA/PS composite polymer latex was blended with commercial PMMA and commercial PS to form the commercial polymer/composite latex polymer blends. The effects of thermal annealing on the morphology of polymer blends were studied. The results showed that the PMMA/PS composite polymer latex had the ability to stabilize the morphology of the polymer blend during thermal annealing.