Chemical modification of styrene based polymers with attaching antimicrobial 4-hydroxybenzoic acid group as a side chain

Free radical copolymerization and cross-linking copolymerization of the 4-chloromethyl styrene (CMS) with styrene (in various mole ratios), were carried out using α,α-azobis(isobutyronitrile) AIBN as initiator and 1,4divinylbenzene (DVB) as a crosslinking agent at 70 oC. The antimicrobial 4-hydroxybenzoic acid (4-HBA) was covalently attached to the obtained copolymers with replacement of all the chlorine atoms in CMS units. The copolymers, obtained in quantitative yields, were characterized by FT-IR and H NMR spectroscopy, differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). The composition of the cross-linked three-dimensional copolymer was determined by FT-IR spectroscopy. DSC showed that incorporation cyclic hydroxybenzoic acid substitute in the side chains of polymers increases their glass transition temperature. The new polymers were found to exhibit excellent bacteriocidal activities.