Antimicrobial additives for polymeric materials

The increasing biofilm-associated infections and antibiotic resistance have stimulated a growing demand both in academic and industry fields for the development of new eco-friendly and not toxic biocides and antimicrobial polymers. To this regard, new antimicrobial polymers containing either organic and inorganic biocides have been realized. In particular, metal-based biocides, silver zeolites, natural substances have been studied. Moreover, imidazolium-based ionic liquids (ILs), a very interesting class of low temperature molten salts, and poly-ionic liquids (PILs) have been synthetized and characterized (1HNMR, MALDI-TOF MS, DSC and TGA). The new ionic liquids synthetized, which differ for the length of carbon chain (9, 14, 16, 18 and 20 carbon atoms) and the type of anion (bromide, hexafluorophosphate, tetrafluoroborate, 1,3-dimethyl 5-sulfoisophthalate, poly(styrene sulfonate), docusate, triflate), have been used as antimicrobial additives in different polymeric matrices, such as PVC, LDPE, PP, SEBS, PEBAX, silicone rubber. Films of the antimicrobial compounds were realized by a Brabender mixer and compression molding or by solvent casting. The analysis of their thermal and mechanical properties (elastic modulus E, tensile stress TS and elongation at break EB), antimicrobial and anticancer activities, together with the release of the antimicrobial agents from the film compounds were carried out (Fig.1). Results showed good antimicrobial properties vs both Gram+ and Gram- bacteria and an interesting anticancer activity.