Antibacterial film from chlorinated polypropylene via CuAAC click chemistry

Polypropylene possessing quaternary ammonium salt (PP-QAS) is synthesized by copper (I)-catalyzed azide- alkyne cycloaddition “click” reaction (CuAAC) starting from chlorinated polypropylene (PP-Cl). The antibacterial properties of PP-QAS have been investigated on gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria. For this purpose, clickable azide functionality has been introduced into PP-Cl backbone by using azidotrimethylsilane (TMS-N₃) - tetrabutylammonium fluoride solution (TBAF) system in tetrahydrofuran (THF) (PP-N₃). Independently clickable alkyne functionalized QAS is prepared by the reaction between 3-dimethylamino-1-propyne and benzyl bromide in the presence of triethyl amine (TEA). Finally, the polypropylene film containing quaternary ammonium salt (PP-QAS) is prepared by the successive CuAAC click reaction and solution casting method. The preparation of PP-QAS is monitored by fourier transform infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (¹H-NMR), differential scanning calorimetry (DSC) and scanning electron microscope (SEM) analyses at various stages. Based on antibacterial activity experiments, the PP-QAS coupons significantly inhibit both the growth of S. aureus and E. coli (p < 0.05) compared to neat PP-Cl and control samples.