Immobilization And Properties Of Mg（OH）₂ Pigment And TiO₂ On Cotton Fabric

Modified magnesium hydroxide（Mg（OH）₂）pigment was used to immobilize onto cotton fabric to impart flame retardant properties via grafting methods.It not only can improve thermal stability of cotton fabric,but also make the fabric colorful.The difference of physical properties and flame retardancy between Atom transfer radical polymerization（ATRP）grafting and photografting was discussed.In addition,tetrabutyl titanate hydrolyzed solution was deposited on cotton fabric via suction filtration to produce cotton/TiO₂ gel,and then TiO₂/C photocatalytic composite was fabricated by calcination in N2.Firstly,Mg（OH）₂ was prepared using ammonia precipitation method.Dye molecules were trapped during the precipitation to obtain Mg（OH）₂ pigment.Then Mg（OH）₂ pigment was silane-modified to have unsaturated carbon-carbon double bonds on the surface of pigment.Finally,Mg（OH）₂ pigment was immobilized onto the surface of cotton macromolecular initiator and cotton fabric via ATRP grafting and photografting,respectively,to obtain flame retardant and colored functional textiles.Mg（OH）₂ pigment and grafted cotton fabric were characterized using FTIR,XRD,TGA and DSC.The physical properties such as tensile,breathable,and dyeing fastness were examined.The results show that the optimal preparation process of flame retardant Mg（OH）₂ pigment is as follows: reaction time of 90 min,reaction temperature of 60 oC,initial concentration of Mg Cl2 of 2mol/L.The optimal process of ATRP grafting is as follows: reaction time of 40 h,reaction temperature of 70 oC,molar ratio of Cu Br and initiator of 2:1,mole ratio of pigment and initiator of 2:1.Continued burning and smoldering time of cotton fabric are 4.2s and 42.8s in the vertical burning test,respectively.Continued burning and smoldering time of grafted cotton fabric are 2.6s and15.6s,respectively,demonstrating that flame retardant effect is obtained after grafting of Mg（OH）₂.The endothermic peaks at 350.4oC,390.1oC and 389.4oC were found for Mg（OH）₂,Mg（OH）₂ pigment and silane modified Mg（OH）₂ pigment,respectively.There is little variation of endothermic peak between Mg（OH）₂ pigment and silane modified Mg（OH）₂ pigment.The weight loss of 29% and 38% were found for Mg（OH）₂ pigment and silane modified Mg（OH）₂ pigment.Thus,modified Mg（OH）₂ pigment has a good flame retardant property.The heat fusion of grafted cotton fabric of 526.7J/g three times higher than pristine cotton fabric of 162.7J/g indicates that grafting of Mg（OH）₂ pigments enhance thermal stability of cotton fabric.The mixture of tetrabutyl titanate as precursor,ethanol as solvent,acetic acid as inhibitor was made.The cotton fabric was dipped into NH4H2PO4 in 24 h and dried.The hydrolyzed tetrabutyl titanate solution was deposited onto cotton fabric with NH4H2PO4 through suction filtration to obtain cotton/TiO₂ gel.The TiO₂/C composite was prepared by calcination in N2.The effect of amount of tetrabutyl titanate,deposition times,calcination time on photocatalytic degradation was discussed to analyze the optimal process of TiO₂/C composite.Moreover,the TiO₂/C composite was characterized.The results show that phtocatalytic anatase type TiO₂ was in-situ synthesized on the cotton fabric using the butyl titanate as precursor.generated in situ on cotton fabric with photocatalytic performance of the nano TiO₂ The optimization of process conditions are butyl titanate volume fraction of 15%,acetic acid volume fraction of 2.5%,calcination temperature of 500 oC and calcination time of 2h.The results also show that after treatment,the shift of endothermic peak to lower temperature and narrower decomposition range were observed,indicating beneficial catalytic carbonization.Catalytic carbonization is beneficial to the decrement of TiO₂ size and improvement of photocatalytic property.