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Preparation and characterization of crosslinked poly(methylmethacrylate) heat sensitive color-developing microcapsules

Puying An, Xinwu Ba, Shuang Lu

The crosslinked poly(methylmethacrylate) (PMMA) heat sensitive color-developingmicrocapsuleswere prepared by emulsion polymerization, in which leucocompound was used as core material and methyl methacrylate and unsaturated hyperbranched poly(amide-ester) aswall-forming materials. The microcapsules were characterized by Malvern particle size analysis, scanning electron microscopy, Fourier transform infrared spectrophotometry (FTIR), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC) and densitometry. Triton X-100 was used as the emulsifier of emulsion polymerization. The effects of the emulsifier content on the particle size distribution andmorphology ofmicrocapsuleswere discussed in detail. The FTIR analysis of leucocompound-containing microcapsules demonstrated that leucocompound was successfully encapsulated in the crosslinked PMMAmatrix. TGA results showed that the prepared microcapsules had good thermal stabilities. The DSC analysis of the resultant microcapsules indicated that the glass transition temperature of the microcapsules was 123.8 °C. The resultant microcapsules had narrower particle size distribution, smoother surface and higher heat sensitive color- developing densitywhen emulsifier mass fractionwas 0.6%.