Abstract:
This research attempted to study the preparation of encapsulated capsule polymer for methyl anthranilate (MA) used as essential oil prototype through suspension polymerization using methyl methacrylate (MMA)-based copolymer as polymer shell. This intended to find out the influence of various parameters such as polymerization method, monomer and MA ratio, type and content of low hydrophilic lipophilic balance (HLB) emulsifier on encapsulation efficiency and free polymer particle formation.
The MA encapsulated capsule polymer was prepared by both micro-suspension conventional (ms CRP) and micro-suspension iodine transfer (ms ITP) polymerizations. It was found that large amount of free polymer particle (36-48 %) occurred in aqueous medium by ms CRP while the free polymer formation was significantly decreased using ms ITP. However, there was no free polymer formation using Iodoform (CHI3) as chain transfer agent at 0.006 mol% related to monomer. Due to high water solubility of MA, encapsulation percent was quite low (42%). To overcome this drawback, various emulsifiers (oleic acid, span 80 and PEG 30 dipolyhydroxystearate (DPHS)) with low HLB value were used to retain MA in the monomer droplet or polymerizing particle. Among three emulsifier, DPHS was the best emulsifier to retain MA in microcapsule giving 58% encapsulation. In addition, MA encapsulated inside the capsule was only released 55% in 87 days.
This can be concluded that MA encapsulated capsule polymer using MMA-based copolymer as polymer shell with quite high percent encapsulation and without free polymer particle was successfully prepared. Due to low releasing of MA, the prepared capsule may be able to use in various applications.