Effects of Protective Colloid on the MF-UF Double Wall Micro-Encapsulation Containing Essence Oil

Abstract

Essence oil is difficult to microencapsulate and difficult to envelop into wall to prepare pressure sensitive microcapsules. With styrene maleic anhydride copolymer (SMA) as the protective colloid, the paper studied the effects of protective colloid and micro-encapsulation of pressure sensitive perfume microcapsules with melamine formaldehyde resin (MF) and urea formaldehyde resin (UF) as double wall first time by using the re-in situ polymerization method. The microcapsules and emusion process were characterized on morphologies, mean particle size and size distribution, zeta potebtial, wall thickness of microcapsules. It was found that the SMA seemed to be suitable for the emulsification and preparation of microcapsule with MF-UF resin as double wall containing essence oil. The results indicated the S/M mole ratio in MSA molecules affected the preparation and quality of microcapsules, pH value and the dosage of SMA had important impact on zeta value and encapsulation in the process of polymerization. The stirring time and stirring rate in emulsification process with MSA as protective colloid influenced the mean particle size and particle size distribution of microcapsules, SMA was one of the components of microcapsules, SMA amount used affected the mean particle size, size distribution and thickness of microcapsules.