Preparation And Application Of Superhydrophobic And UV-Resistant Cotton Fabric Finishing Agent

The superhydrophobic and UV-resistant fabric not only has the unique wettability of the superhydrophobic surface,but also possesses strong resistance against ultraviolet rays,having broad application prospects.At present,zinc oxide or titanium dioxide nanoparticles are mostly used in the preparation of superhydrophobic/anti-UV fabrics,but they are all limited by photocatalytic activity.In this paper,non-toxic and non-photocatalytic nano-silica was used as the base material to prepare multi-functional finishing agent.The anti-ultraviolet/super-hydrophobic cotton fabric was obtained by layer-by-layer self-assembly method.The specific research work is as follows:（1）The 2,4-dihydroxybenzophenone（UV-0）was modified to prepare 2-hydroxy-4-glycidyl ether benzophenone（HEPBP）.The structure of HEPBP was characterized by FT-IR,¹H NMR and ultraviolet absorption spectra.The HEPBP was grafted onto the silica to obtain SiO₂-H particles,which not only enhanced the UV protection of the silica,but also improved the thermal stability of the HEPBP.Infrared demonstrated the presence of HEPBP units on the silica surface.Thermogravimetric analysis indicated that the grafting ratio of HEPBP on silica was about 4.74%.（2）In addition to being used as a UV protection agent,SiO₂-H particles were also used as to construct the rough structure upon the surface of fabric which was one of the requirements for obtaining superhydrophobic surfaces.（PDDA/SiO₂-H）@HDTMS superhydrophobic/UV-resistant functional coating was constructed on the surface of cotton fabric by electrostatic self-assembly.The effects of preparation conditions on the hydrophobic properties of fabrics were systematically investigated.The surface morphology and composition of the fabrics were studied by SEM and XPS.The self-cleaning,antifouling ability and UV protection,abrasion resistance and washing resistance of the fabrics were investigated.The experimental results showed that when the mass concentration of SiO₂-H and HDTMS was 0.5wt%and 3wt%,respectively,and the number of assembled layers was 3,the contact angle of cotton fabric was153°,exhibiting excellent self-cleaning and antifouling properties.The T（UVA）,T（UVB）and UPF values were 1.26%,0.36%and 208.49,respectively,displaying excellent UV protection performance.After 300 abrasion times or 20 washing times,the static contact angle of the fabric was still greater than 140°,and the UPF values were 89.10 and 75.54,respectively,demonstrating excellent washing and abrasion resistance.（3）The HEPBP was grafted onto polyethyleneimine（PEI）to synthesize PEI-H.The graft modification not only imparted the ultraviolet absorption property to PEI,but also improved the thermal stability of HEPBP.FT-IR,¹H NMR and ultraviolet absorption spectra confirmed the structure of the target product.PEI-H was used both as a cationic polyelectrolyte and as an organic UV absorber.The PEI-H/SiO₂@HDTMS superhydrophobic/UV-resistant multilayer film was constructed on the surface of cotton fabric by electrostatic self-assembly.The surface morphology and composition of the fabric were studied by SEM and XPS.The self-cleaning and antifouling ability,UV protection,washing resistance,abrasion resistance,safety and air permeability of the fabric were investigated.The results showed that when the HDTMS concentration was 3wt%and the number of assembled layers was 3,the fabric exhibited excellent anti-fouling and self-cleaning properties with a WCA of 154°and a SA of 6°.The UPF of fabric was 686.63,achieving excellent UV protection performance.This method could effectively avoid agglomeration of silica particles.The dispersibility and uniformity of silica particles upon（PEI-H/SiO₂）@HDTMS fabric surface were superior to（PDDA/SiO₂-H）@HDTMS fabric,so the UV protection property,washing and abrasion resistance of the former functional coating were better than that of the latter.After 300 abrasion or 20 washing times,WCA of fabric was greater than 140°and the UPF value was beyond 400,displaying high hydrophobicity and excellent UV protection.The modified fabric met the requirements of the highest standard of"Baby Products"in"Standard 100 by OEKO-TEX"（2018）.The coating had little effect on the air permeability of the fabric.