玉米秸秆木质素氧化与改性的研究

采用傅里叶变换红外光谱(FTIR)、紫外-可见光谱(UV-Visible)、核磁共振(1H NMR)以及热重TG分析技术对玉米秸秆木质素被二氧化氯氧化前后的结构变化及其与呋哺甲醇改性的产物进行了表征.红外光谱显示木质素骨架中的芳香环基团被有效氧化开环,在被氧化后的木质素中出现C=O共轭羰基伸缩振动特征峰.紫外光谱显示木质素在被氧化后位于280 nm处的紫外吸收显著降低.核磁共振波谱显示,木质素中连接在芳香环侧链的甲氧基数量被氧化后出现显著的降低.同时,呋喃甲醇的改性能有效增加木质素其芳香环侧链原子数.热重分析表明呋喃甲醇的改性反应能有效地改变木质素的热分解性质,生成具有热稳定性更好的木质素改性高聚物.

Study on the Corn Stover Lignin Oxidized by Chlorine Dioxide and Modified by Furfuryl Alcohol

The Fourier transform infrared spectroscopy(FTIR),ultraviolet-visible spectroscopy(UV-Visible),nuclear magnetic resonance spectroscopy(1H NMR)and TG analysis were used to study the oxidation of corn stover lignin by chloride dioxide and subsequently modified by furfuryl alcohol.The results were as following:The selective oxidation of lignin by chlorine dioxide was obtained by spectroscopy study.FTIR showed that the characteristic absorbance peaks of aromatic units were decreased after chloride dioxide oxidation.The increased absorbance for the band around 1 720 cm-1 corresponding to carbonyl stretching was achieved in the oxidized lignin and the lignin modified with furfuryl alcohol.The ultraviolet-visible spectroscopy showed that the absorbance around 280 nm was largely reduced after the lignin was oxidized.The 1H NMR spectroscopy also showed the decrease of aromatic units and methoxyl group in the oxidized lignin.All these indicated the formation of muconic acid and ester,or quinone derivatives when the lignin was selectively oxidized by chloride dioxide.The modification by furfuryl alcohol made the oxidized lignin more thermally stable.