大豆秸秆和毛竹碱木素的逐级分离及性状表征

Fractionation and Characterization of Lignin from Soybean Stalk and Bamboo Pulping Black Liquor

中文关键词:  碱木素  逐级分离  分子质量  粒径

Key Words:alkali lignin  fractionation  molecular weight  particle size

中文摘要:

      采用酸析法分别对大豆秸秆和毛竹的硫酸盐制浆黑液中的碱木素按不同pH值进行逐级分离,探讨了黑液中碱木素在酸析过程中的溶出规律；采用凝胶渗透色谱(GPC)、红外光谱(FT-IR)、动态光散射(DLS)对不同条件下酸析得到的各级碱木素进行分析与比较。结果表明,逐级分离后,各级碱木素的相对分子质量分布变窄,分子质量有相当程度的重叠；随着pH值的降低,各级碱木素的粒径逐渐减小,相对分子质量及其多分散性也逐渐减小,说明酸析法是分离不同分子质量碱木素的一种有效方法。

Abstract:

      In this thesis, acid precipitation method was used to separate alkali lignin from soybean stalk and bamboo kraft pulping stalk liquor. The molecular weights of alkali lignin separated under different pH values were compared. The dissolving characters of lignin under acidic condition were studied. Fourier transform infrared spectroscopy (FT-IR), gel permeation chromatography (GPC) and dynamic light scattering (DLS) were used to analysis structure and molecular weight of alkali lignin samples. It was found that after being fractionated, the molecular weight distribution of alkali lignin became narrower. The molecular weight and particle size of alkali lignin which was precipitated decreased continuously with decreasing of pH value. It indicated that acid precipitation process was an effective method for fractionation of alkali lignin with different molecular weights.