Selective distribution of silica grafted with crosslinked poly(methyl methacrylate) in poly(methyl methacrylate)/poly (styrene-co-acrylonitrile) blend

The selective distribution of silica nanoparticles(NPs) grafted with crosslinked poly(methyl methacrylate) (PMMA) in PMMA/poly(styrene- co -acrylonitrile) (SAN) blend is investigated by varying the crosslinking degree of grafted PMMA. NPs grafted with highly crosslinked PMMA chains mainly tend to be located in the PMMA-rich domains, while NPs grafted with linear PMMA chains mainly tend to be distributed at the interface of blend matrix. NPs grafted with slightly crosslinked chains are located partially at the interface and partially in the PMMA-rich domains. The deviation between the theoretical predication and actual location of modified NPs may be related with the heterogeneity of miniemulsion polymerization. Furthermore, different location of three modified NPs induced by different grafted chain structure may result in their various compatibilization effects on PMMA/SAN blend. NPs grafted with linear or slightly crosslinked PMMA aggregate at the interface of blend matrix to form the jamming structure and further inhibit completely the domain coarsening.