阻燃剂对二氧杂环己烷木质素的热降解行为和成炭过程的研究

THE STUDY OF FLAME RETARDANTS ON THERMAL DEGRADATION AND CHARRING PROCESS OF DIOXANE LIGNIN IN THE CONDENSED PHASE

二氧杂环己烷木质素用Pepper法从水曲柳中分离、提纯,再分别用聚磷酸铵、磷酸二氢铵和硼酸进行处理后,采用XPS、FTIR和TGA技术对木质素的热降解及其成炭行为进行研究.TGA实验在高纯氮环境中进行,其结果显示:阻燃剂的添加降低了木质素的热降解温度、促进了炭层的形成.XPS实验在高真空条件下进行,所得数据表明:阻燃剂的加入使得C1s总强度和C-C键的C1s强度增加,然而降低了C-O键的C1s强度和C1s轨道结合能.用FTIR观察残余炭层的结构,发现C-O键的吸收强度减弱,而芳环骨架的振动吸收和芳环上C-H键的振动吸收增强.

Dioxane lignin was isolated from manchurian ash by means of Pepper's method. The thermal degradation and the charring of the ash lignin treated with ammonium polyphosphate, ammonium phosphate or boric acid in the condensed phase were investigated by the combination of XPS, FTIR and TGA. TGA results under pure nitrogen showed that the flame retardants reduced the initial temperature of thermal degradation of the lignin and promoted char formation compared with the control sample. XPS data obtained in high vacuum showed that an increase of C1s and (C-C) intensity, a decrease of C1s (C-O) intensity and a decrease of C1s binding energy were promoted by the flame-retardants. FTIR data of char residue showed that flame retardants reduced the relative absorbance of C-O group and enhanced the relative absorbance of C-H vibration in aromatic ring and of aromatic ring vibration.