A derivative of chito-oligosaccharide (COS), N-(2-hydroxyl)propyl-3-trimethyl ammonium chito-oligosaccharide chloride (HTACC), was synthesized using a reaction of glycidyltrimethylammonium chloride (GTMAC) and COS prepared by depolymerization of a fully deacetylated chitosan. COS and HTACC were applied to the cotton fabrics with a pad-dry-cure process using the reaction between the hydroxyl group of cellulose and terminal aldehyde group in COS and HTACC. Their minimum inhibition concentration (MIC) was evaluated, and the antimicrobial activity and durability to laundering of cotton fabrics treated with them were compared. The complete substitution of NH 2 groups in COS with GTMAC was obtained at a 4 : 1 mol ratio of GTMAC to NH 2 in 18 h at 80°C under the presence of acetic acid. MIC values of the 1.04 DS of HTACC and COS were 50 and 400 g/mL, respectively. A cotton fabric treated with 0.2% of HTACC and 1.8% of COS exhibited 100% reduction of bacteria. At the 50th laundering cycle, 0.3% of HTACC and 2.4% of COS indicated 100% bacterial reduction.

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A commercial m-aramid as N-halamine precursor has been coated onto polyethylene terephthalate (PET) fabric surface by pad-dry-curing process. The process is accomplished by padding the scoured PET fabric through the homogeneous m-aramid solution, drying at 150 C for 3 min, and curing at 230 C for 3 min. The PET surface coated with m-aramid was characterized using fourier transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). FTIR exhibits new bands in the 1645 and 1524 cm À1 regions as characteristic of m-aramid bands, which indicate the PET fabric coated with m-aramid. XPS results show a distinguishable peak at binding energy 398.7 eV, which confirms the nitrogen atom of m-aramid on the PET surface. In addition, SEM image shows a layer of coating onto the PET surfaces, which demonstrates the presence of m-aramid coating on the surface of the PET. After exposure to dilute sodium hypochlorite solution, exhibition of antimicrobial activity on the coated PET is attributed to the conversion of N-halamine moieties from the N-halamine precursor. The chlorinated PET showed high antimicrobial activity against Gram-negative and Gram-positive bacteria. The chlorinated PET coated with 10% m-aramid exhibited about 6 log reductions of S. aureus and E. coli O157:H7 at a contact time of 10 and 30 min, respectively. Furthermore, the antimicrobial activity was durable and rechargeable after 25 wash cycles.

Poly(vinyl alcohol) (PVA) was blended with m-aramid as an N-halamine precursor for imparting antimicrobial activity. A series of PVA/m-aramid blend films were produced with different ratios of PVA/m-aramid by weight (100/0, 100/2, 100/6, 100/10, and 100/ 50). The films were characterized using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and thermogravimetric analysis (TGA). The FTIR spectra of the PVA/m-aramid blends are a combination of the spectra of pure PVA and of pure m-aramid. However, the peak intensity in the m-aramid decreases with decreasing m-aramid content from 50 to 2 wt % in PVA. It implies the compatibility of m-aramid in the PVA/m-aramid blend films. Furthermore, a single glass transition temperature (T g ) for all blend films by DSC confirms that PVA/m-aramid is successfully miscible. The crystallinity of PVA/m-aramid blend films decreases slightly with increasing m-aramid content in the blend films. This agrees with the results obtained by WAXD. However, melting point and thermal stability of the blend films increases with increasing m-aramid content in the blend films. Chlorinated PVA/2% m-aramid blend film produces about 5.7 log reduction of both Gram-positive and Gram-negative bacteria at 30 min contact, implying sufficient antimicrobial activity. Therefore, PVA/m-aramid blend films may serve as a novel material for biomedical applications.