Preparation of Temperature and Water Responsive Microcapsules Containing Hydroquinone with Spray Drying Method

It was tried to prepare temperature and water responsive microcapsules containing hydroquinone as a water soluble core material with the spray drying method. Microcapsules were composed of ethyl cellulose (EC), methyl cellulose (MC) and P-N-isopropylacrylamid (PNIPAM). P-N-isopropylacrylamid and methyl cellulose were used as a temperature responsive polymer and as a water responsive polymer, respectively. Ethyl cellulose was the main shell material of microcapsule. At the microencapsulation process, the core and shell materials were dissolved in ethyl alcohol dissolving water (20 wt%) and then, spray-dried to prepare microcapsules. In the fundamental operation, the concentration and molecular weight of methyl cellulose were mainly changed. The releasing rate of hydroquinone was repressed at 40°C and increased at 20°C due to temperature responsive PNIPAM. Furthermore, responsibility to water was increased with the concentration of methyl cellulose.