Microencapsulation of Ammonium Bicarbonate by Phase Separation and Using Palm Stearin/Carnauba Wax as Wall Materials

Abstract

Abstract Ammonium bicarbonate microcapsules (AMBCMC) were prepared by phase separation method using palm stearin/carnauba wax (CNW) as wall materials. The morphology of AMBCMC showed that the microcapsules were mainly spherical shapes. DSC analysis results suggested that the microcapsule shells began melting at the temperature 47.9 °C, while the shells were thoroughly destructed at the temperature above 78.1 °C. The particle sizes of AMBCMC were chiefly distributed in the range of 30 ~ 300 μm. Ammonium bicarbonate (AMBC) in microcapsules was highly stable under different relative humidity, and AMBCMC was hardly damaged even at 95% relative humidity. The thermal stability of AMBC increased, while AMBC encapsulated in microcapsules still could decompose and release gas at 70 °C as well as free AMBC. Furthermore, AMBC encapsulated in microcapsules showed strong survivability in the presence of citric acid. The results indicated that the stability and compatibility of AMBC were effectively increased after microencapsulation.