麦草微波碱法制浆中木质素基团变化趋势研究

Research on the Structural Changes of Wheat Straw Lignin during Microwave Alkaline Pulping

通过傅立叶变换红外光谱技术初步研究了碱法麦草蒸煮制浆中木质素的结构变化。通过不同微波辐射功率、温度、时间不同蒸煮制浆,分析黑液中木质素的红外谱图,可看出木质素中羟基溶出量均随着蒸煮温度、时间、功率的增加先增加后减少;随着温度升高,紫丁香基木质素和愈创木基型木质素的溶出量先增加后减少,在较短时间内,二者均大量溶出,而功率对二者溶出量影响较小,且可看出蒸煮温度、功率对木质素甲氧基溶出量在蒸煮过程中影响较小,时间较长时,木质素甲氧基溶出量增加;温度过高,时间过长,功率过大都会使木质素醚键发生断裂。

By Fourier transform infrared spectroscopy,the structural changes of wheat straw lignin during microwave alkaline pulping were studied. The effects of microwave power,temperature and time on the infrared spectra of lignin were observed. The results indicate that with the increases of cooking temperature,time and microwave power,the dissolution of hydroxyl group,syringyl unit and guaiasyl unit in lignin increases first and then decreases. Both syringyl and guaiacyl lignin could dissove obviously in a relative short time. The microwave power has small effect on the dissolution of syringyl and guaiacyl lignin. The effects of cooking temperature and microwave power on the dissolution of methoxyl are smaller than that of cooking time. Too high temperature,too long cooking time and too high microwave power result in the cleavage of lignin ether bonds.