Preparation and properties of antibacterial styrene‐acrylic emulsion based on bis‐quaternary ammonium salt‐containing mono‐methacrylates as polymerizable antibacterial agents

With the aim to prepare antibacterial styrene‐acrylic emulsion, a series of bis‐quaternary ammonium salt‐containing mono‐methacrylates MEQABr‐x(x = 12, 14, 16) were synthesized as polymerizable antibacterial agents via two steps. The chemical structures of MEQABr‐x(x = 12, 14, 16) were confirmed by proton nuclear magnetic resonance (1H‐NMR) and Fourier transform infrared (FTIR). The Minimum inhibitory concentration (MIC), Minimum bactericidal concentration (MBC), and Critical micelle moncentration (CMC) results showed that MEQABr‐x(x = 12, 14, 16) had antibacterial properties and surface properties which was influenced by its alkyl chain length. The antibacterial emulsion (SAQx‐n) was synthesized by emulsion polymerization of styrene (St), butyl acrylate (BA), acrylic acid (AA) and MEQABr‐x(x = 12, 14, 16). The structures of its films (SAQx‐n‐F) were characterized by attenuated total reflectance‐FTIR. The effects of MEQABr‐14 content or alkyl chain length of MEQABr‐x(x = 12, 14, 16) on emulsion and its films were investigated in the aspect of particle sizes, pencil hardness, adhesive force grade, thermal stabilities, surface morphology, particle morphology, and so forth. The films (SAQx‐9‐F) with 9 wt% content of MEQABr‐x(x = 12, 14, 16) showed the nearly 100% antibacterial rate against Escherichia coli and Staphylococcus aureus, indicating its potential to be used as antibacterial coating.