Preparation, Characterization And Application Of New And Efficient Halamine Antibacterial Cotton Fiber Material

In this thesis, three kinds of water-soluble N-halamine precursors,(5,5-dimethylhydantoinyl-1) methyl-dimethylamine DHDA,(3-chloro-2-hydroxypropyl)-(5,5-dimethylhydantoinyl-1)methyl-dimethylammoniumchloride CDDAC, and3-(dimethylamino-ethyl)-5,5-dimethylhydantoin, have beensynthesized. Their compositions and structures were characterized by ElementalAnalysis, Mass Spectrometry, Nuclear Magnetic Resonance, and Fourier TransformInfrared Spectroscopy. Novel high-efficacy antimicrobial cotton fibers grafted withquaternarized N-halamines were prepared by dipping-drying-curing method tocovalently bond these N-halamine precusors onto the surface of cotton fibers, thenby chlorination in a diluted NaClO solution to endow N-halamine structures on thecotton fibers. The main contents are as follows:1. Water-soluble N-halamine precursor DHDA was firstly synthesized through adehydration reaction between1-(hydroxymethyl)-5,5-dimethylhydantoin anddimethylamine in2-propanol under room temperature. After reaction was over, thesolvent could be collected by evaporation for reuse.2. CDDAC, a water-soluble quaternarized N-halamine precursor, was firstlysynthesized by a quaternariztion reaction between DHDA and epichlorohydrin inhydrochloric acid solution at room temperature.3. A water-soluble N-halamine precursor containing tertiary amine group,3-dimethylamino-ethyl-5,5-dimethylhydantoin, was firstly synthesized. Ethanol aminereacted with thionyl chloride for1h at35-50℃after completely mixed by stirring under ice bath, then ethanol was added and heated to boiling point. Aftercooling,crystallization, filtration, and drying, the white crystal of2-chloroethyldimethylamine hydrochloride was obtained. Finally,2-chloroethyldimethylamine hydrochloride reacted with5,5-dimethylhydantoin andsodium ethoxide to produce3-dimethylamino-ethyl-5,5-dimethylhydantoin.4. The reaction solution of CDDAC was directly used to graft CDDAC onto thecotton fabrics. The grafted cotton fabrics had powerful antimicrobial property aftersoaked in the diluted NaClO solution. We followed the concept of greenenvironmental protection and avoided the use of organic solvents during the graftingprocess to reduce the production cost and pollution to the environment.5. The mixture of DHDA and epichlorohydrin in water was directly used forgrafing DHDA onto the fabric to form quaternarized N-halamine precusor graftedcotton fibers which was transferred to quaternarized N-halamine antimicrobial onesupon exposure to dilute sodium hypochlorite solution. The grafting process is safeand eco-friendly since no hydrochloric acid and organic solvents were used.Interestingly, the grafting and chlorination processes didn’t cause the obviousdecrease of the tensile strength of cotton fabrics.6.3-dimethylamino-ethyl-5,5-dimethoxylhydantoin was mixed withepichlorohydrin in water under room temperature. After mixed thoroughly, thesolution was directly used for grafting to prepare quaternarized N-halamine precusorgrafted cotton fibers. The quaternarized N-halamine antimicrobial cotton fibers wereobtained after chlorination and the content of oxidative chlorine (Cl+) on theantimicrobial cotton fabers was about0.08%which was enough to quickly killharmful microorganisms.7. The antimicrobial tests were performed for quaternarized N-halamineantimicrobial cotton fibers grafted with CDDAC and DHDA. The results showed thatboth the antimicrobial fibers grafted with CDDAC and the ones grafted with DHDAhad high-efficacy antimicrobial property and their antimicrobial efficiency againstEscherichia coli and Staphylococcus aureus could reach100%within5min of contacttime. In addition, it was found that these antimicrobial cotton fibers had goodwashing durability and stability.