Preparation Of Nano Magnesium Hydroxide And Study On The Flame Retardant Finishing Of Silk Fabrics

The regulations concerning the environmental protection are becoming increasingly rigid and severe,and thus green,eco-friendly and energy conservation and emission reduction have gradually become one of the possible directions in the development of textile industry.However,some traditional flame retardants,such as titanium/zirconium metal salts,halogenated flame retardants and phosphorus-containing flame retardants with potential formaldehyde release,can not meet the basic requirements in daily life.Therefore,in recent years,non-halogenated,nano-scale,and environmentally friendly flame retardants have attracted significant attention.Particularly,the nano modification of inorganic flame retardant materials such as magnesium hydroxide and aluminum hydroxide has turned to be one of the research hot topics in recent years.Firstly,the magnesium hydroxide nanoparticles with a uniform particle size of 50 nm were successfully prepared by using magnesium chloride hexahydrate as raw material and sodium hydroxide and ammonia as precipitant.In order to improve the stability of magnesium hydroxide nanoparticles in aqueous solution,silane coupling agent KH-550 was used to modify nanometer magnesium hydroxide.The activity index of magnesium hydroxide nanoparticles(4%)modified by 4%KH-550 reached 95.6%,demonstrating that magnesium hydroxide nanoparticles were completely modified,and obtained large surface energy and improved compatibility.Then,the as-prepared magnesium hydroxide nanoparticles were applied to improve the flame retardancy of silk fabric through impregnation method.The optimized finishing process was:modified magnesium hydroxide nanoparticle concentration was 0.7 mol/L,bath ratio was 1:50,temperature was 80?,time was 1 h.The treated silk fabric obtained a high limiting oxygen index(LOI)of 32.2%and a low damage length of 9.5 cm;it also had significantly suppressed heat release and smoke generation capacity compared with the untreated one.After 10 washing cycles,the treated silk fabric could still self-extinguish in the vertical burning test,and had a damage length of 14.8 cm and a high LOI value of 25.8%,suggesting that the silk fabrics treated with the magnesium hydroxide nanoparticles had good flame retardancy and washing durability.In addition,compared with the commercial magnesium hydroxide particles,the as-prepared magnesium hydroxide nanoparticles showed better flame retardancy and smoke suppression performance on silk fabric.With the aim of further improving the flame retardant property of the treated silk fabrics,zinc chloride was applied together with modified magnesium hydroxide nanoparticles in the treating process.It was found that the treatment with modified magnesium hydroxide nanoparticles followed by the treatment of zinc chloride solution could impart better flame retardant ability to silk fabric with good washing durability.The treated silk fabric had a high LOI value of 36.6%,and a low char length of 6.5 cm;it could still self-extinguish in the vertical burning test and obtained a low damage length of 8.3 cm after 10 washing cycles.