Preparation Of Halogen-free Flame Retardant Cotton Fabric And Study On Its Flame-retardant Characteristics

Cotton fabric,as a best-selling product in the world,has the advantages of wide source,comfortable wearing and good air permeability.However,the limiting oxygen index(LOI)of cotton fabric is only 18.0,which is flammable and seriously affects its application in the market.Therefore,it is necessary to treat cotton fabric with flame retardant.Therefore,two intumescent flame retardant systems are selected to treat cotton fabric.The main research contents are as follows:1.A new flame-retardant cotton fabric was prepared by physical impregnation with Tri-(hydroxyethyl)isothiocyanate(THEICIC)and ammonium polyphosphate(APP).The flame retardant cotton fabric was tested by horizontal combustion.The flame retardant of cotton fabric was studied by vertical combustion test,limiting oxygen index(LOI),thermogravimetric analysis(TG)and scanning electron microscopy(SEM).The experimental results showed that when THEIC/APP was 1:3,the soaking time of cotton fabric in finishing solution was 40 min.When the baking temperature is 100 ?,The damage length is 8.3 cm and the flame retardant effect is improved.The horizontal combustion test shows that the spread rate of the product is 72.6 mm/min lower than that of pure cotton fabric,and the flame retardant effect is up to the national requirement;TG analysis showed that when the temperature reached 750 ?,the residual carbon content of flame-retardant cotton increased by 19.5%than that of untreated cotton fabric.The SEM observation showed that the surface of flame-retardant cotton fabric had spherical adhesion before combustion,and the fiber surface was covered with expanded carbon layer after burning.The intumescent carbon layer can insulate oxygen and heat emission in the combustion process,so it can play a better role in flame retardation.2.The flame retardant cotton fabrics were prepared by chemical grafting of P-S system.The flame retardant properties of cotton fabrics were studied by means of horizontal combustion test.The LOI value reached 32.6,the flame retardant effect reached the national B1 standard,and the horizontal combustion test showed that the flame retardant cotton fabric extinguished when the flame source left,and the flame retardant effect was improved and reached the national requirements;TG analysis showed that when the temperature increased to 750 ?,the carbon residue rate of flame-retardant cotton fabric reached 40.0%?while that of pure cotton fabric was only 10.5%.The results show that the addition of flame retardant agent can obviously increase the carbon residue rate.The dense carbon layer can be observed on the surface of the flame-retardant cotton fabric after burning by SEM.The carbon layer is beneficial to hinder the decomposition of the cotton fabric and play a protective role on the flame-retardant fabric.