Effect of emulsion preparation method on microencapsulation of <i>n</i>-octadecane using melamine-formaldehyde pre-polymers

Abstract

The microcapsules containing <i>n</i>-octadecane as the core material and melamine-formaldehyde resin as the wall material have been synthesized by <i style="">in situ</i> polymerization method. A systematic study has been carried out to investigate the effect of the method used in the preparation of reaction emulsion mixture, and the curing conditions used during the encapsulation process on the properties of microcapsules. The microcapsules so obtained are characterized for their core content, encapsulation efficiency, mean particle size distribution, and thermal & solvent stability. Using the modified encapsulation process with a formaldehyde-to-melamine molar ratio of 8 and core-to-wall ratio of 2, microcapsules with a high core content of 70% and a heat storage capacity of >160 J/g could be obtained. The capsules are found to be stable at temperatures more than 80 °C and to cyclohexane wash.