Synthesis of Poly(Methyl Methacrylate)/Silica Nano-composites. III. Block Copolymer with Lamellar Structure

Abstract

Three types of poly(methyl methacrylate)-block-poly(methyl methacrylate-co-2-hydroxyethyl methacrylate) [PMMA-block-P(MMA-co-HEMA)] block-random copolymer and two types of poly(methyl methacrylate)-block-poly(2-hydroxyethyl methacrylate) [PMMA-block-PHEMA] were synthesized by atom transfer radical polymerization as precursor polymers for PMMA/silica nano-composites. Nano-composite films of PMMA/silica were synthesized by the reaction of perhydropolysilazane (PHPS) with precursor polymers in 1,4-dioxane and the cast of the 1,4-dioxnae solutions. The effects of the localization of HEMA unit in PMMA-block-P(MMA-co-HEMA) block-random copolymer and the amount of PHPS to HEMA in feed on the microphase separation of nano-composites were investigated. Microphase separation of the nano-composites was observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). It was found that the sub-micrometer silica domains were homogeneously dispersed in a wide area in the nano-composites. The thermal properties of the nano-composites were measured by differential scanning calorimetry and thermogravimetric analysis.