Preparation of polymeric microcapsules using modified calcium carbonate as a template
University of New Brunswick
Microcapsules consisting of acrylamide, methyl methacrylate and styrene were prepared via in-situ polymerization on the surface/inside pores of modified calcium carbonate particles as templates, followed by the dissolution of the carbonate cores in hydrochloric acid solution. The capsules were further modified via copolymerization with diallyldimethylammonium chloride (DADMAC) and N-isopropylacrylamide (NIPAM) using similar templates in an attempt to improve their properties. The microcapsules were characterized using confocal laser fluorescence microscopy (CLSM) and scanning electron microscopy (SEM). The adsorption and release properties of these capsules were studied. Results showed that the adsorption of dye on capsules did not occur as both Langmuir and Freundlich models were unfitting despite the high linear regression values. The addition of DADMAC improved the absorbtion of methylene blue while slightly decreasing the cumulative amount released. On the contrary, although NIPAM did not make a significant difference to the adsorption of the cationic dye it did however accelerate the release at 37°C, implying the thermal responsive behaviour induced by NIPAM segments incorporated into the capsules.