Gamma irradiation-induced pH-responsive poly(methyl methacrylate- acrylic acid-divinyl benzene) hybrid polymer particles for dye treatment

Abstract

ABSTRACT The environmentally friendly method is used to fabricate spherical poly(methyl methacrylate-methyl acrylate-divinylbenzene) (P(MMA-MA-DVB)) hybrid particles by gamma irradiation-induced suspension polymerization without an initiator. The MMA: MA: DVB of 60: 20: 20 was used to encapsulate 10 wt% oleic coated-magnetic nanoparticles using ultrasonication for monomer droplet preparation. A stable suspension with approximately 90% monomer conversion was produced using 5 kGy gamma-ray to initiate the polymerization. A large quantity of submicrometer-sized free polymer particles as a by-product was formed in an aqueous medium where the radicals were generated by gamma irradiation of water. However, the number of free polymer particles decreased with the decrease in monomer droplet size. The obtained particles were hydrolyzed to form P(MMA-AA-DVB) particles presenting a negative surface charge (> −30 mV) in an alkaline condition. It was found that the prepared particles presented dye adsorption efficiency as the methylene blue (MB) concentration reduced with adsorption time. The MB adsorption efficiency also increased with pH due to the presence of PAA as a pH-responsive material. Moreover, the hybrid polymer particles were easily separated by the application of an external magnet. Therefore, the fabricated pH-responsive hybrid polymer particles would be served as an alternative dye adsorbent for wastewater treatment.