Research On The Preparation Of Multifunctional Textiles Based On Covalent Organic Framework

As an extension of human skin,advanced textile fiber products such as functional textiles and smart textiles enhance people’s communication with the external environment,and are more and more concerned by people,with good application prospects and practical value.Traditional cotton textiles have poor water repellency,weak UV protection,and cannot respond to changes in the external environment.Therefore,the preparation of multifunctional cotton textiles with water repellency,UV protection and intelligent response remains a challenge.Covalent organic framework materials（COFs）are a kind of porous crystalline powder materials used in sensing,adsorption and catalysis,and the composite of COFs and textiles can enhance the added value of textiles and meet people’s pursuit of high-grade multi-functional textiles.In this paper,the research progress of COFs and COFs in textiles is reviewed and analyzed,and then COF-based multifunctional textiles are successfully prepared by loading imimine-type COF materials on the surface of cotton textiles under room temperature using cheap,widely sourced and excellent performance as the substrate.Research has been carried out in the following three areas:（1）Using cotton fabric as the substrate,using dimethyldehyde-containing monomer terephthalaldehyde（PDA）and 2,5-dimethoxyterephthalaldehyde（DMA）and triammonia-containing organic monomer 1,3,5-tris（4-aminophenyl）benzene（TAPB）,covalent organic framework materials were grown in situ on the surface of cotton fabric,and two composite functional textiles（Cotton@PDA-TAPB@PDMS）were obtained by further modification of polydimethylsiloxane（PDMS）.Cotton@DMA-TAPB@PDMS),and its application in oil-water separation and UV protection was studied.The surface morphology,chemical composition and structure of the composite functional textiles prepared by scanning electron microscopy（SEM）,Fourier infrared spectroscopy（FT-IR）,X-ray energy spectroscopy（XPS）and X-ray diffraction（XRD）were systematically and comprehensively characterized,and their wettability,UV protection performance and mechanical stability were tested.The influence of acetic acid concentration,organic monomer concentration and reaction time on the properties of modified textiles was explored.The results showed that the reaction time of 12 M acetic acid was 72 h when the concentrations of PDA and TAPB were 4 m M and 2.67 m M;respectively,and the composite functional textiles showed superhydrophobicity（WCA=151.2°）and UV protection（UPF=76.3）.At concentrations of DMA and TAPB of 4 m M and 2.67 m M,respectively,the reaction time was 72h,and the composite functional textiles were prepared showing superhydrophobicity（WCA=152.4°）and UV protection（UPF=87.3）.The final prepared superhydrophobic anti-ultraviolet fabric,after multiple washes and sandpaper polishing,its ultraviolet protection performance and superhydrophobic properties basically did not change,showing good mechanical stability.（2）In order to investigate the acid-base sensitivity of the prepared imine COF modified textiles（Cotton@DMA-TAPB,CDT）,the color-changing performance and color-changing stability of functional textiles under different acid-base conditions,as well as the color-changing properties and color-changing stability of functional textiles in acid/alkaline steam.The results showed that when the pH value of the solution was reduced from 7 to 5,the COF modified textile changed from yellow to orange.When the pH value is reduced from 5 to 1,the COF modified textile changes from orange to red,and the flexible fabric sensor prepared changes color sensitively and rapidly,and can produce color change in a short time（<1 s）,and the color change is durable.After 50 response discoloration cycles in the solution of pH=1 and pH=13,the K/S value of the modified textile changed from 14.5 to 13.8,the chromatic differenceΔE was 2.7,and the difference before and after the discoloration of the pH-responsive chromic fabric was obvious（the chromatic differenceΔE was 59.7）,and the modified textile had excellent stability in response to discoloration.Modified textiles also show large color changes in acid/alkaline steam and have better recovery capacity in five acid/alkaline vapors.（3）To investigate the photocatalytic co-degradation dye properties of imimine COF modified textiles（Cotton@DMA-TAPB,CDT）.The change in absorbance at different times was analyzed by UV/Vis spectroscopy,and the dye concentration change was calculated.The effects of different light sources on the catalytic degradation performance of CDT fabrics were studied,the degradation ability of CDT fabrics on different dyes rhodamine B（Rh B）,methyl orange（MO）and methylene blue（MB）was explored,the effects of different dyes on the catalytic degradation of Rh B dye solutions at different pH were studied,the cyclic stability of CDT fabrics for dye degradation was studied,and the degradation mechanism of CDT as a photocatalyst for dyes was speculated.The results showed that the time for Rh B to reach complete degradation（about 120 min）under ultraviolet light was shorter than that required by sunlight（about 300 min）.Within 2 h,the adsorption rates of 0.2 g CDT fabric on Rh B,MO and MB dye reached 40.86%,13.66%and 62.60%,respectively,and the degradation rates of Rh B,MO and MB dye solution were 97.93%（60 min）,98.10%（60 min）and 98.00%（120min）,respectively,and CDT fabric had excellent adsorption synergistic photocatalytic degradation performance.CDT fabrics have a faster degradation rate in neutral and alkaline dye.Finally,the mechanism of photocatalytic degradation of dyes in CDT fabrics was speculated,and the main active substances（·O₂^-and ¹O₂.）in the photodegradation process were detected by adding different free radical scavengers.