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A series of comb-like ionenes (C-ionenes) with aliphatic side chains were prepared via the Menschutkin reaction from amine, epichlorohydrin, and N, N, N′, N′-tetramethyl-1,6-hexanediamine. The structures of the resulting ionenes were characterized by means of charge density, H-NMR, and C-NMR. The antimicrobial properties of the ionenes were also investigated by measuring the minimum inhibition concentration (MIC) against Escherichia coli ( E. coli). The corresponding antimicrobial dynamics were studied by detecting the UV absorbance of the E. coli suspension. It was found that in comparison to the linear ionenes (L-ionenes), C-ionenes exhibited lower MIC values and faster antimicrobial effect influenced by the side chains. In particular, C-ionene with 4-carbon side chains showed MIC at 7.8 μg/mL and its aqueous solution (31.2 μg/mL) inhibited 99.9 % E. coli within 2 min. The morphologies of C-ionenes in aqueous solution were investigated by measuring their particle sizes and zeta potentials. In addition, the anti-mold tests against Aspergillus niger and Chaetomium globosum suggested that the comb-like ionenes were effective at inhibiting the growth of the fungi. [ABSTRACT FROM AUTHOR]

In this work, an antimicrobial guanidine polymer (PHGH) was grafted onto starch as a carrier to form branched or grafted chains along the starch backbone. This grafting improved the antimicrobial properties and the adsorption of the starch on recycled cellulose fibers. Similar work was also conducted on bleached sulfite fibers for comparison. The results showed that the starch, grafted with 12 wt% PHGH, adsorbed more on recycled fibers than on sulfite fibers. By applying the antimicrobial-modified starch to recycled or sulfite pulps up to 20 mg/g, both antimicrobial and antimold performances of the papers were improved substantially. Additionally, the PHGH-modified starch increased the tensile index of papers, but decreased the tear index slightly. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to investigate the morphologic changes of Escherichia coli bacteria and Chaetomium globosum fungi upon exposure to the PHGH-modified starch, thus demonstrating that the antimicrobial mechanism is based on the damage of bacterial membrane. [ABSTRACT FROM AUTHOR]

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The antimicrobial thermoplastic starch (ATPS) containing guanidine-based polymers was obtained using a twin-screw extrusion with potato starch and polyhexamethylene guanidine hydrochloride (PHGH). Furthermore, the non-leaching antimicrobial biodegradable poly(butylene adipate-co-terephthalate) (PBAT) was prepared through reactive extrusion with PBAT and ATPS in the presence of the coupling agent, 2,2′-(1,3-phenylene)-bis (2-oxazoline) (PBO). Finally, the antimicrobial PBAT films were obtained by using a blown film extrusion system. The mechanical properties of the antimicrobial PBAT films varied with the contents of ATPS and thermoplastic starch (TPS). According to the test results of shaking flask method, the prepared antimicrobial PBAT films showed excellent antimicrobial activities (antimicrobial rate > 99.99%) and rapid pathogen deactivation efficiency (antimicrobial rate > 99.99% even within 15 s of contact time). The water washing and ring diffusion tests demonstrated that the antimicrobial film was a non-leaching product. Inspiringly, the antimicrobial PBAT films with an excellent antimicrobial activity can be obtained even at a very low dosage of PHGH (1.0 mg/g PBAT film). [ABSTRACT FROM AUTHOR]