Fabrication Of Superhydrophobic And Flame-retardant Cotton Fabric And Polyurethane Sponge Via Dip-coating

Cotton fabrics and polyurethane sponges have good dyeability,flexibility,moisture absorption and air permeability,and are commonly used in household and car accessories.However,cotton fabrics and polyurethane sponges are flammable,which is a hidden danger in fire accidents.In order to improve the fire safety of cotton fabrics and polyurethane sponges,the construction of flame-retardant coating on the surface is a simple and efficient method.Nevertheless,flame-retardant coating displayed poor water resistance.When being immersed in water,the flame retardant in coating is easy to release,thereby resulting in the destruction of flame retardancy.Therefore,endowing flame-retardant coating with superhydrophobicity can effectively improve the water resistance,which is of great significance for maintaining the flame retardancy.In this work,dip-coating,a simple and easy method,was used to prepare superhydrophobic and flame-retardant cotton fabrics and polyurethane sponges by constructing superhydrophobic and flame-retardant coating on the surface,and the applications in the fields of self-cleaning,oil-water separation and fire-warning were also studied.The main contents and results are listed as follow:(1)The phytic acid(PA)/1-[3-(trimethoxysilyl)propyl]urea(UPTMS)composite was deposited on the surface of cotton fabric to obtain PA/UPTMS-CF.Then 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide modified silica(DOPO-SiO₂)and polydimethylsiloxane(PDMS)composite coating(DOPO-SiO₂@PDMS)was constructed on the surface of PA/UPTTMS-CF,and the superhydrophobic and flame-retardant cotton fabric(SFR-CF)was finally fabricated.SFR-CF showed a water contact angle(WCA)of 156°,and possessed outstanding self-cleaning property,acid and alkali resistance and oil-water separation ability.Furthermore,SFR-CF showed the excellent flame retardancy,and self-extinguished quickly in vertical burning test.CCT test indicated that in contrast to pristine cotton fabric,peak heat release rate(PHRR)and total heat release(THR)of SFR-CF were significantly decreased.TG,TG-FTIR results and the investigation of residue showed that PA and DOPO in DOPO-SiO₂decomposed to form polyphosphoric acid to promote the dehydration and charring of cellulose in the combustion,and the dense protective char layer was generated on the surface of cotton fabric.Meanwhile,the pyrolysis volatiles of SFR-CF were significantly decreased,which efficiently reduced the risk in fire accident.SFR-CF exhibited extensive prospect of application in the area of decoration with anti-fouling property and flame retardancy.(2)The composite of montmorillonite(MMT)and iron hydroxide oxide(FeOOH)(MMT@FeOOH)was directly deposited on the surface of polyurethane sponge(PUS)to obtain MMT@FeOOH-PUS.ThenMMT@FeOOH-PUSwasmodifiedby perfluorooctyltriethoxysilane(PFOTES),and the superhydrophobic and flame-retardant PUS(SFR-PUS)was finally prepared.XRD,ATR-FTIR and XPS were carried out to investigate the chemical composition of SFR-PUS,and SEM and WCA were adopted to study the surface morphology and hydrophobicity of SFR-PUS.The results showed that the lamellar fold-like surface roughness was constructed by MMT@FeOOH on the surface of PUS.SFR-PUS had a WCA of 154°,and also showed excellent anti-adhesion property and oil absorption ability.In addition,the pyrolysis products of SFR-PUS were significantly reduced in comparison with pristine PUS.SFR-PUS self-extinguished within 15 s after igniter was removed in burning test and the skeleton structure still kept intact.The investigation of residue showed that the physical barrier property of MMT@FeOOH and the catalytic charring effect of FeOOH and MMT significantly improved the flame retardancy of SFR-PUS.(3)The graphene oxide(GO)sheets were stitched via the hydrogen bond of phytic acid(PA)and GO,and then Fe₃O₄was wrapped by the stitched GO sheets.The obtained PA-GO@Fe₃O₄composite was deposited on the surface of PUS to gain PA-GO@Fe₃O₄-PUS.Subsequently,the GO sheets in PA-GO@Fe₃O₄-PUS were reduced by hydroiodic acid(HI)vapor to obtain PA-RGO@Fe₃O₄-PUS.After the modification with PFOTES,the superhydrophobic and flame-retardant PUS(SFR-PUS)was finally prepared.ATR-FTIR,XPS,XRD,LRS,SEM and WCA were adopted to study the chemical composition,surface morphology and hydrophobicity of SFR-PUS.SFR-PUS possessed a WCA of 156°and outstanding anti-adhesion property and water-oil separation ability.Furthermore,SFR-PUS displayed excellent flame-retardant property,and self-extinguished within 4 s after igniter was removed in burning test.SFR-PUS also showed excellent fire-warning capability with a fire-warning time of only 2.1s.SFR-PUS has a wide application prospect in fire-warning materials in outdoor condition.