Comparative Performance of Three Magnesium Compounds on Thermal Degradation Behavior of Red Gum Wood

Materials

Yiqiang Wu¹  Chunhua Yao¹  Yunchu Hu¹  Xiaodan Zhu¹  Yan Qing¹ 

[1] College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China; E-Mails:

关键词: magnesium compounds;    fire retardant;    wood;    thermal degradation;   

DOI  :  10.3390/ma7020637

来源: mdpi

【 摘 要 】

The effect of basic magnesium carbonate (BMC), magnesium hydroxide (MH), and magnesium chloride hydrate (MCH) on thermal degradation of red gum wood was studied using cone calorimetry, Thermogravimetric-differential scanning calorimetry (TG-DSC) analysis, and X-ray diffraction (XRD) characterization. The results showed common fire retardation actions of the three compounds by releasing incombustible gas and/or water vapor to dilute combustible gas in the flaming zone, and by converting to MgO, which had a satisfactory protective wall effect on the wood. Individually, BMC absorbed heat from the wood at the pre-decomposition stage and, thus, slowed down wood pyrolysis process. It slightly increased the char yield by charring in both the charring stage and the char calcination stage. MH lost water at about 270°C, close to the temperature at which wood thermally degraded. MH rendered wood char quickly, and the compact char layer impeded further carbonization and burning of inner wood. MCH promoted charring with Mg²⁺ as a Lewis acid, and increased wood char yield. MCH also released Cl· free radical and HCl at 167°C, which easily coordinated with combustion reaction radical, and slowed down, even inhibited, the combustion chain reaction.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland