One-pot synthesis of polystyrene bead bearing surface charge for dye adsorption

Abstract

Preparation of polystyrene bead bearing surface charge was carried out using one pot suspension polymerization of styrene and divinylbenzene (DVB) in the presence of cationic functional monomer, (3-methacryloylamino) propyl trimethyl ammonium chloride (MAPTAC), using K[subscript 2]S[subscript 2]O[subscript 8] and AIBN as initiators. Firstly, polymerization of MAPTAC in aqueous solution using K[subscript 2]S[subscript 2]O[subscript 8] initiator was performed for the determined time to generate poly(3-mehtacryloylamino) propyl trimethyl ammonium chloride (PMAPTAC) radical. Secondly, the mixture of styrene, DVB, and AIBN initiator was fed into the solution of PMAPTAC radicals and then allowed the polymerization to proceed for another certain time. During the stage of polymerization of styrene and DVB, incorporation of PMAPTAC radicals onto the bead surface took place, resulting in the final bead partice comprised two layers (from SEM result); the inner core of the poly (styrene-co-DVB) support and the outer layer of copolymerization adduct of styrene, DVB, and PMAPTAC radical revealed by FTIR analysis. Factors affecting particle size, size distribution and surface functionality (PMAPTAC segment) were investigated. Of all synthetic parameters, types of surfactants and amounts of DVB were found to play an important role in controlling the particle size and the surface functionality, respectively. Anionic dye adsorption was carried out in order to evaluate the performance of the bead as ion exchange resin. Adsorption mechanism involved the opposite charge interaction between the bead cationic group and the dye anionic group. The adsorption capacities, following the Langmuir model, were also reported.