Abstract

Jittaya Sadchaiyaphum¹, Pongsathon Phapugrangkul², Preeyporn Chaiyasat^1,3 and Amorn Chaiyasat*^1,3

DOI : http://dx.doi.org/10.13005/ojc/350202

High encapsulation efficiency of magnetite nanoparticles (MNPs; Fe₃O₄) in microcapsules using PDVB as a hydrophobic polymer shell was successfully achieved by microsuspension conventional radical polymerization (ms CRP). MNPs were initially synthesized by co-precipitation of Fe₂⁺/Fe₃⁺ in a binary phase. During the nucleation of MNPs in alkaline aqueous solution existing oleic acid (OA), MNPs were coated with OA (MNPs-OA) before moving to the toluene phase with the addition of salt. At OA concentration of 0.3 wt%, most of the nucleated MNPs were hydrophobic and well dispersed in the toluene phase. Using DVB as a monomer for ms CRP, high encapsulation efficiency (92 %EE) of MNPs-OA was obtained, with low free polymer particle formation. By contrast, large amounts of free polymer particles were observed at low %EE (32%) of MNPs. The main driving force for high %EE was obtained by coating the surface of the MNPs by OA which increased hydrophobicity.

Encapsulation Efficiency; Magnetite Nanoparticles; Microsuspension Conventional Radical Polymerization; Microcapsule

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