Study On Finishing And Functionalization Of Cotton Fabric Based On Nitrogen And Boron Doped Carbon Quantum Dots

With the development of The Times and the deepening of environmental damage,people not only have the requirements for clothing comfort,but also increased the demand for UV protection and self-cleaning,so green and environmentally friendly carbon quantum dots with good UV protection performance are increasingly paid attention to and used by people.It can be used in the modification of cotton fabric by virtue of its high UV absorption and excellent photoelectric properties.In this paper,nitrogen and boron doped carbon quantum dots（BN-CQDs）with good UV absorption,high fluorescence and photoelectrocatalytic efficiency were prepared by hydrothermal method and characterized.BN-CQDs/isocyanate microcapsules and BN-CQDs/Ti O₂ sol-gel were used to finish the surface functionalization of cotton fabric by spraying,rolling and curing method.On this basis,BN-CQDs/graphene oxide（GO）/polyvinyl alcohol（PVA）was loaded or deposited on the surface of cotton fabric by ion crosslinking.The effects of BN-CQDs/microcapsules,BN-CQDs/Ti O₂ and BN-CQDs/GO on the UV resistance,water resistance and self-cleaning properties of cotton fabric under different finishing processes were discussed.The research is mainly carried out in the following three aspects:（1）The change of washable resistance of cotton fabric was studied:BN-CQDs were prepared by hydrothermal method,microcapsules were prepared by interfacial polymerization method,and BN-CQDs/microcapsules were finished on the fabric surface by spray-roll-curing method.The effects of different volume ratios of BN-CQDs and microcapsules on UV protection and water resistance of the modified fabric were investigated,and the structures and properties of the prepared BN-CQDs and microcapsules were characterized.Fourier infrared spectrometer（FT-IR）,Malvern laser particle size analyzer,transmission electron microscope（TEM）,X-ray photoelectron spectroscopy（XPS）,ultraviolet visible spectrometer（UV-Vis）,fluorescence spectrometer（PL）,scanning electron microscopy（SEM）were used to investigate the structure and properties of BN-CQDs,microcapsules and fabrics By characterization,BN-CQDs and microcapsules containing rich functional groups were successfully prepared and arranged on the surface of fabric.BN-CQDs has a graphene-like interlayer structure,low crystallinity,particle size of 5-8 nm,good UV absorption ability and fluorescence properties.The fluorescence and physical properties of the modified fabric were characterized by ultraviolet protection tester,three-purpose ultraviolet analyzer,fabric tensile strength test and computer fabric permeability tester.The results showed that when the volume ratio of BN-CQDs/microcapsules was 10:3,the UPF value（UV protection factor）of A3 of cotton fabric reached 35.1.Even after 20 washes,UPF value decreased by 11%,and the fabric still had bright blue fluorescence under UV lamp.The strength and moisture permeability of the modified fabric were still good.It was concluded that the composite system of microcapsules and BN-CQDs improved the fabric’s water resistance.（2）The change of the self-cleaning performance of the fabric was studied:Ti O₂ was prepared by sol-gel method,and BN-CQDs/Ti O₂ sol-gel was prepared on the surface of the fabric by spraying,rolling and curing method.The influence of different volume ratios of BN-CQDs/Ti O₂ on the UV resistance and self-cleaning performance of the fabric was investigated.The structure,morphology and properties of the fabric were characterized by FT-IR,UV-visible absorption spectrum and scanning electron microscopy.The results showed that Ti O₂ also had good UV absorption ability,and Ti O₂ and BN-CQDs were successfully arranged on the surface of the fabric,and BN-CQDs reacted with Ti O₂ to form O-Ti-O bond.And the modified fabric surface fibers did not change greatly.The fluorescence,self-cleaning and physical properties of the modified fabric were characterized by ultraviolet protection tester,three-purpose ultraviolet analyzer,fabric tensile strength test and computer fabric permeability tester.The results showed that the BN-CQDs/Ti O₂ fabric could decompose methylene blue（MB）under the condition of light irradiation.When the volume ratio of B3 fabric is 10:10,the UPF value of B3 fabric is 34.1,which is increased by 189%,and the K/S value is reduced to 6.41,which is decreased by 71%.At the same time,the modified fabric also has bright blue fluorescence under ultraviolet lamp,and the strength and moisture permeability of the fabric are better.It is concluded that BN-CQDs/Ti O₂ fabric has better self-cleaning performance.（3）The changes of UV resistance of the fabric were studied:the fabric was first treated with alkalization and cationization,and then the BN-CQDs/PVA/GO composite system was finished on the fabric surface by ion crosslinking.The effects of different volume ratios of BN-CQDs/PVA/GO on the UV resistance and water resistance of the fabric were investigated.The morphology,structure and properties of the fabric were characterized by FT-IR and SEM tests.The results showed that BN-CQDs,PVA and GO were all finished on the surface of the fabric,and the fibers were expanded by alkali-cationization treatment,but still did not break.PVA formed a film on the surface of the fabric.The fluorescence,self-cleaning and physical properties of the modified fabric were characterized by UV protection tester,three-purpose UV analyzer,fabric tensile strength tester and computerized fabric permeability tester.The results showed that the UV resistance of the modified fabric was greatly improved by using ion crosslinking.When the volume ratio was 80:15:16,The C6 UPF value of BN-CQDs/PVA/GO fabric reached the maximum 191.5,which increased by 1521%compared with the unmodified fabric,and still reached 161 after 20 times of washing,which decreased by about15.9%.The modified fabric has bright blue fluorescence under ultraviolet lamp,the strength is still good,but the moisture permeability has decreased to a certain extent.The results of this study provide some guidance for improving the functional finishing of cotton fabrics.