Preparation Technologies Of MgAl-LDHs For Flame Retardant Of Bamboo And Its Flame Retardant Properties

Bamboo has been widely used in building materials,furniture and decorative materials in China.However,bamboo is flammable.In order to improve the flame retardant performance of bamboo,the magnesium-aluminum layered double hydroxide?MgAl-LDHs?was prepared by urea hydrolysis method in this article.The effects of reaction conditions on the thermal stability of MgAl-LDHs and the flame retardancy of MgAl-LDHs after treatment with bamboo were investigated.The primary achievements are as follows:?1?MgAl-LDHs were prepared by urea hydrolysis with using magnesium nitrate,aluminum nitrate and urea as raw materials.The effects of reaction time,static crystallization time and molar concentration of reactants on the particle size and thermal stability of MgAl-LDHs were investigated.The following conclusions can be obtained:The reaction time was extended from 6 h to 48 h.When the reaction time was 36 h,the thermal stability was the best.The static crystallization time was extended from 0 h to 15 h.When the static crystallization time was 10 h,the thermal stability was the best.The molar concentration of the reactant[Mg²⁺]increased from0.072 mol/L to 0.792 mol/L,and the thermal stability was the best when the molar concentration[Mg²⁺]was 0.528 mol/L.?2?Bamboo with MgAl-LDHs coating was prepared by in-situ reaction using magnesium nitrate,aluminum nitrate and urea as raw materials.The reaction conditions of MgAl-LDHs coating and the flame retardant properties of the treated bamboo were studied.The following conclusions can be obtained:The reaction time was extended from 6 h to 48 h,and the MgAl-LDHs formed on the surface of the bamboo gradually became uniform and dense.When the reaction time was 24h,the MgAl-LDHs coating formed on the surface of the bamboo reached saturation;compared with untreated bamboo,the ignition time of bamboo with MgAl-LDHs coating was extended by 11s,the peak of heat release rate was reduced by 42.9%,the rate of smoke release was reduced by 77.3%,and the coating of MgAl-LDHs had anti-wear properties.?3?The bamboo material was treated successively with sodium hydroxide and MgAl-LDHs under normal temperature and pressure.The FT-IR test showed that the bamboo treated with sodium hydroxide exposed a large amount of hydroxyl groups,and it was easier to combine with the hydroxyl groups in MgAl-LDHs,thus fixing more MgAl-LDHs;the cone calorimeter test found that Compared with bamboo,the bamboo with MgAl-LDHs coating has more excellent flame retardant property,the peak of heat release rate is reduced by 29.12%,and the smoke release rate is reduced by 40.45%.