Preparation Of N-halamine Treated Cotton Fabrics With Antibacterial And UV Resistance Properties

There are many pathogenic microorganisms existing in human living environment,which threaten people's daily life seriously.Due to the porous structure of textiles,bacteria could be attached and grown on textiles easily.Most infectious pathogens use textiles as the medium to spread and threat the health of humans.With the increasing awareness of the human health and environmental protection,much more attention has been aroused to develop antibacterial materials,especially antibacterial textiles.Antibacterial agents such as nanometals and their oxides,chitosan,quaternary ammonium salt,quaternary phosphine salt and N-halamine compounds are drawing more attention than before.For antibacterial textiles,the antibacterial treating agents should have good antibacterial property,not affect the properties of the fabric,and be harmless to human body and the environment.Due to the broad-spectrum against bacteria,high antibacterial property,eco-friendly and rechargeability,N-halamine becomes the desirable choice for antibacterial processing of textiles.It is urgent to improve the UV stability of N-halamine compounds since the antimicrobial ability would loss due to the broken of N-Cl or other covalent bonds between N-halamine and materials under UV light irradiation.To prepare high-efficient and UV-stable N-halamine antibacterial fabrics,several methods were applied in this study as follows.The organic ultraviolet protective agent BPTCD and BHMEC were selected to finish the cotton fabric with N-halamine precursor to improve the UV stability.Considering the advantages of size effect and optical properties,ZnO and AgCl nanoparticles were used with N-halamine precursors to prepare antibacterial textiles with good UV stability.At the same time,the reaction rate of DCC/DMAP system,ultraviolet-induced grafting,electron beam radiation grafting,thiol-ene click chemistry,and plasma-induced grafting were compared to obtain cotton fabrics with high modification efficiency,excellent antibacterial performance and good UV stability.Aminoethyl hydantoin(NDMH)was synthesized with 5,5-dimethylhydantoin and2-chloroethylaminehydrochloride,which was characterized by ~1H-NMR.BPTCD was coated on the cotton fabrics through a traditional pad-dry-cure process,and carboxyl group was introduced on the surface of the cotton fibers.After grafting aminoethyl hydantoin on the surface of BPTCD coated cotton in DCC/DMAP system through amidation reaction,antibacterial fabrics were obtained after chlorination with sodium hypochlorite.The modified fabrics showed good antibacterial property and could inactive 9.70×10~6 CFU of S.aureus and5.20×10~6 CFU of E.coli O157:H7 within 10 min and 30 min,respectively.The UPF of the modified cotton fabric was 42.25.After 24 h UV light irradiation,44%of the chlorine content of the treated cotton was remained and about 89%of chlorine could be recharged after rechlorination.The tensile strength retention rates of the modified fabric in the warp and weft directions were 81.6%and 76.4%,respectively.However,the reaction time of DCC/DMAP system needed 24 h,and the reaction rate should be improved.3-Allyl-5,5-dimethylhydantoin(ADMH)was synthesized by 5,5-dimethylhydantoin and3-allyl bromide,and was characterized by 1H-NMR.Due to the diphenylketone structure of photosensitizer BPTCD,UV irradiation induced the graft copolymerization of ADMH on the fiber surface after BPTCD was coated on the fabric.The prepared sample could kill 100%of S.aureus and E.coli O157:H7 within 10 min.The UPF of the modified cotton fabric was43.17.After 24 h UV light irradiation,50%of the chlorine content of the treated cotton was remained and 93%of original chlorine could be recharged upon exposure to an aqueous sodium hypochlorite.The warp tensile strength retention rate of the modified fabric was72.4%,and the weft tensile strength retention rate was 67.5%.The grafting reaction induced by UV irradiation only needed 25 min,and the reaction rate was significantly increased,and the UV stability was also improved to some extent.BHMEC as ultraviolet absorbent and ADMH as N-halamine precursor were dissolved in acetone to form the finishing solution.The cotton fabric was soaked and rolled in the finishing solution.The antibacterial and anti-UV cotton fabric was prepared by the electron beam co-irradiation process.The modified fabric could kill 9.70×10~6 CFU of S.aureus and5.20×10~6 CFU of E.coli O157:H7 within 10 min.The UPF of the modified cotton fabric was46.95.48%of the chlorine content of the treated cotton was remained after 24 h UV light irradiation,and 91%of the chlorine content could be recovered after rechlorination.The ultraviolet stability and chlorine recoverability of the treated cotton were good.The modified fabric showed good washing stability and storage stability.After finishing,the warp strength retention rate was 68.9%and the weft strength retention rate was 65.2%.Electron beam co-irradiation grafting has realized the antibacterial and anti-UV functions via one-bath finishing.The reaction efficiency was higher,while the strength loss was larger.Considering that the ultraviolet irradiation induced grafting and electron beam irradiation induced grafting caused great damage to the tensile strength of cotton fabric,thiol-ene click reaction was used to obtain antibacterial and anti-ultraviolet cotton fabric.The cotton fabric was pretreated with nano ZnO sol,and then treated with 3-mercaptopropyltriethoxysilane.ADMH was introduced on the surface of the pretreated fabric under the UV light initiation.After chlorination,the treated samples showed good antibacterial efficacy against S.aureus and E.coli O157:H7.About 1.13×10~6 CFU of S.aureus and 2.67×10~6 CFU of E.coli O157:H7 could be completely inactivated within 1 min and 5 min,respectively.The UPF of the modified cotton fabric was 42.65.After 24 h of UV irradiation,47%of the active chlorine content was remained,and 93%was recovered after rechlorination.The warp tensile strength retention rate of the modified fabric was 80.8%,and the weft tensile strength retention rate was 75.3%.The thiol-ene click reaction required only 10 min of UV irradiation,the reaction condition was mild and the reaction rate was fast.In order to further improve the reaction rate,low temperature plasma-initiated grafting was adopted to prepare the antibacterial and anti UV cotton fabric.Silver chloride nanoparticles were deposited on the surface of the cotton sample by continuous and alternating impregnation,and the cotton fabric was soaked and rolled in the finishing solution of ADMH.After drying at room temperature,the antibacterial and anti-ultraviolet fabric was obtained by plasma-initiated grafting.The obtained sample showed excellent antibacterial properties and could inactivate 100%of S.aureus and E.coli O157:H7 within 1 min.The silver chloride and N-halamine compounds showed good synergistic antibacterial effects in the antimicrobial test.The UPF of the modified cotton fabric was 56.45.After 24 h of UV irradiation,54%of the active chlorine content was remained,and 92%was recovered after rechlorination.The weft and warp tensile strength retention rates of the fabric were 84.3%and80.2%,respectively.The grafting reaction initiated by low temperature plasma only needs to be treated for 3 min.The reaction rate was very high,and the strength retention rate of the fabric was good.In summary,the cotton fabrics with good antibacterial property and UV stability were prepared by the above five experimental methods.The DCC/DMAP system needed to pretreat BPTCD on cotton fabric,and the reaction with NDMH took 24 h with a low reaction rate.BPTCD was also pretreated on cotton fabric in UV irradiation induced grafting.The graft reaction only took 25 min under UV irradiation,but the tensile strength damage of the fabric was serious.Electronic beam irradiation grafting achieved the one-step finishing of cotton fabric with N-halamine antibacterial function and anti-UV function,and the reaction efficiency was high,but the tensile strength loss was too high.The thiol-ene click reaction only needed 10 min under UV irradiation.The reaction rate was fast and the strength retention rate was good.However,zinc oxide and sulfhydryl group needed to be introduced into the fiber step by step.The grafting initiated by low temperature plasma required loading silver chloride onto the fiber first,and the treatment time was only 3 min.The reaction rate was fast and the strength retention rate was good.