麦草碱法浆残余木质素特性的研究

Characterization of Residual Lignin in Alkaline Pulp of Wheat Straw

本文用纤维素酶酶解法分别从麦草、碱法麦草浆中分离制备出三种酶木质素样品(CEL、RL-1、RL-2),并以CEL作对比,用物理和化学的方法对RL-1和RL-2的特性进行了研究。研究结果表明:在低温蒸煮阶段,主要发生的反应是碱易溶木质素和以碱易溶LCC方式存在的木质素的物理溶出,经过此阶段残留在浆中的木质素是亲液性较差的较大分子本质素;在高温蒸煮过程中,木质素发生了大分子碎片化反应和缩合反应,残留在浆中的是平均分子量较低,酚型单元含量和缩合程度较高的木质素。本文认为LCC不是影响成浆残余木质素的主要因素,并推测大部分残余木质素是被截留在细胞壁内的木质素。高缩合程度至少是部分残余木质素难以脱除一个重要原因。

Two residual lighihs in alkaline pulps of wheat straw (Triticum aestivum; were isolated oy selectively hyoroiyzing ana dissolving the carbohydrate in pulps with cellulytic enzymes after purification. The residual lignins were characterized by functional group analysis, molecular weight determination as well as oxidative degradation and compared with that of cellulose enzyme lignin (CEL) from the same material. It was found that most of the component in the residual lignin has no chemical linkages with carbohydrate. In addition, a much higher proportion of condensed structure was found in the residual lignin than in the native lignin. It was suggested that most of the component in the residual lignin is trapped in the cell wall.