Synthesis Of Boron Nitrogen Doped Carbon Quantum Dots And Its Application In UV-resistant Cotton Fabrics

Carbon quantum dots(CQDs)have received widespread attention as a new type of fluorescent nanomaterials.Because of its good water solubility,low toxicity,simple preparation and unique optical properties,it is widely used in the fields of biological/chemical sensors,photocatalysis and cell imaging.In view of the strong absorption capacity of CQDs in the ultraviolet region,it can be used as an anti-ultraviolet finishing agent for cotton fabrics.In this paper,three different carbon sources of boron-nitrogen co-doped carbon quantum dots(BNCQDs)were synthesized by hydrothermal synthesis,and the structure and optical properties of the prepared BN-CQDs were characterized.Fabric cellulose modified grafting BN-CQDs to finish cotton fabric in two ways.The influence of carbon quantum dots on cotton fabric morphology,structure and UV resistance was discussed.This article mainly conducted the following three aspects of research:(1)Using citric acid,ammonium citrate and glucose as the carbon source,ethylenediamine as the nitrogen source,and borax as the boron source,three different carbon sources of BNCQDs(C1,C2)were synthesized by a one-pot hydrothermal method.,C3).Its morphology,structure and composition were characterized by Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),X-ray diffractometer(XRD),and transmission electron microscope(TEM).And use ultraviolet absorption spectrometer(UV-Vis)and fluorescence spectrometer(PL)to characterize its optical properties.The results show that the prepared carbon quantum has a spherical structure with a size of 3-8 nm,mainly composed of C,N,O,and B.The surface is rich in graphite-like oxygen,nitrogen and boron functional groups.Nano crystals have good water solubility.The three aqueous solutions of BN-CQDs all have good ultraviolet absorption capacity in the 240 nm and 347 nm ultraviolet regions,and the absorption intensity of C1 is the highest.Under 365 nm ultraviolet light irradiation,the three BN-CQDs solutions all emit bright blue light.When the excitation wavelength increases from340 nm to 380 nm,the emission peaks of the three BN-CQDs are all located at 435 nm,showing BN-CQDs The photoluminescence behavior has nothing to do with the excitation wavelength,but the fluorescence emission intensity of C1,C2,and C3 decreases successively,which is mainly caused by successively decreasing the content of oxygen-containing functional groups of non-radiative functional groups on the surface.Based on the unique optical properties of carbon quantum dots,it can be considered as an ultraviolet shielding agent for cotton textiles.(2)The spraying-rolling method is used to finish cotton fabrics with three carbon sources BN-CQDs solution,BN-CQDs/polyvinyl alcohol(PVA)solution and BN-CQDs/water-based polyurethane(WPU)solution respectively,through UV protection Measure the ultraviolet protection factor(UPF)through the tester,and carry out the washing resistance test,select the BN-CQDs synthesized by the appropriate carbon source and the best finishing process.The results showed that,on the one hand,the cotton fabrics treated with carbon quantum dots synthesized from the three carbon sources all showed excellent UV resistance and reached a very good protection level.However,the washing resistance of the three finished cotton fabrics is different.-CQDs/water-based polyurethane(WPU)mixed water solution finishes cotton fabrics with the best washing resistance,followed by BN-CQDs/polyvinyl alcohol(PVA)mixed aqueous solution finishing cotton fabrics,and BN-CQDs solution directly finishing cotton fabrics have the best washing resistance.The worst performance,this is mainly because PVA and WPU form a polymer film on the surface of the fabric fiber,which enhances the interaction between the carbon quantum dots and the fiber,and the hydrophilicity of PVA is greater than that of WPU,so the PVA film is in the washing process It is easier to fall off than WPU film;on the other hand,by comparing the performance of cotton fabrics treated with BN-CQDs solution of three different carbon sources,it is found that the cotton fabrics treated with citric acid carbon source BN-CQDs solution have the best UV protection ability.Well,this is mainly because BN-CQDs with citric acid as the carbon source have the highest UV absorption intensity.(3)The cellulose of cotton fabric was modified with glycidyl trimethyl ammonium chloride to obtain a cotton fabric with quaternary ammonium cation cellulose,and then the quaternary ammonium cation on the surface of the cotton fabric and the surface of BN-CQDs were used.The carboxyl groups of the carboxyl groups generate ionic bonds to obtain quaternary ammonium salts,and BN-CQDs are grafted onto the surface of cotton fabrics to obtain a cotton fabric that can emit bright blue light under ultraviolet light.The structure and morphology of cotton fabrics are characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR),UV transmission tester,digital camera and other tests.The results showed that the carbon quantum dot particles were successfully grafted to the surface of cotton fabrics,which improved the washing resistance of cotton fabrics,and the finished cotton fabrics emitted bright blue light under the irradiation of ultraviolet lamps,and the UV protection coefficient of cotton fabrics was as high as 81.4.And after washing ten times in standard water,it still remained at 75.3.Achieve a very good level of protection.