Phase-transfer-agent-aided polymerization and graft copolymerization of acrylamide



The use of phase-transfer catalysts, with water-insoluble initiators, for polymerization and graft copolymerization reactions was explored. The polymerization of a water-soluble vinyl monomer, acrylamide (AAm), and the graft copolymerization of AAm onto a water-insoluble polymer backbone, isotactic polypropylene (IPP), with a water-insoluble initiator, benzoyl peroxide (BPO), and a phase-transfer catalyst, tetrabutyl ammonium bromide (Bu4N+Br), were carried out in a water/xylene binary solvent system. The conversion percentage of AAm into polyacrylamide (PAAm) and the percentage of grafting of AAm onto IPP were determined as functions of various reaction parameters, such as the BPO, AAm, and phase-transfer-catalyst concentrations, the amounts of water and xylene in the water/xylene mixture, the time, and the temperature. The graft copolymer, IPP-g-PAAm, was characterized with IR spectroscopy and thermogravimetric analysis. By a comparison of the results of the phase-transfer-catalyzed graft copolymerization of AAm onto IPP and the preirradiation method, it was observed that the optimum reaction conditions were milder for the phase-transfer-catalyst-aided graft copolymerization. Milder reaction conditions, including the temperature, the time of reaction, and a moderate initiator (BPO), in comparison with high-energy γ-rays, led to better quality products, and the reaction proceeded smoothly with high productivity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2364–2375, 2004