Analysis on thermal properties of hemp needle-punched felt treated by Mg(OH)_2

The flame-retardant finishing of the hemp needle-punched felt was performed with Mg(OH)_2(mass concentration(300 g/L)) and adhesive(volume concentration 20%) with imprenating time(20 min.) The thermal properties the hemp needle-punched felt before and after flame retardant finishing were analyzed by using thermo gravimetry(TG) and differential thermal analysis(DTA).The results revealed that the hemp needle-punched felt treated by Mg(OH)_2 has the initial pyrolysis stage 0～(330 ℃,) the main pyrolysis stage 330～(400 ℃,) and the residual pyrolysis stage 400～(600 ℃.) The speed of hot weightlose and maximum hot weightlose reduces obviously,and the rate of remains of the carbon increases and the initial temperature of thermal decomposition increases.The first exothermic peak value reduced 50%,no second exothermic peak is observed,indicating that the Mg(OH)_2 has imparted good flame-retardant effect to the hemp needle-punched felt.