Fabrication of durable and non-leaching triclosan-based antibacterial polypropylene

Despite achieving broadscale commercial applications, Polypropylene (PP) is prone to bacterial contamination, which poses huge threats to public health. Applying antibacterial agents in polymer matrix is recognized as a widespread method to endow PP biocidal properties. Herein, we report a preparation of triclosan (TCS) based antibacterial PP through free radical grafting. As the methyl acrylate group is introduced to the TCS in advance to synthesize a radical-active monomer (f), PP-f products are successfully prepared via two typical free radical grafting reactions, solution grafting (PP-f-sg) and melt grafting (PP-f-mg). Although showing high f content (up to 12.7 mol%), PP-f-sg samples are of low monomer utilization (less than 50%) and the grafting reaction must be assisted by comonomers. On the contrary, PP-f-mg samples with modest f content (from 0.08 to 0.34 mol%) reveal satisfying monomer efficiency (over 80%) without the help of any comonomers, which demonstrates significant advantages. When addition amount of f reaches 0.12 mol% (1.0 wt%), antibacterial rates (R) of PP-f exceed 99% against both E. coli and S. aureus. Since covalent bonds are formed between TCS and PP chains, the biocidal properties of PP-f are durable and non-leaching. The R of PP-f maintains over 90% after ethanol extraction, while those extracted samples made by physical blending of TCS and PP completely lose their antimicrobial properties.