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首页> 外文期刊>Journal of Wood Chemistry and Technology >Effect of Kraft Cooking Conditions on the Chemical Composition of the Surface and Bulk of Spruce Fibers
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Effect of Kraft Cooking Conditions on the Chemical Composition of the Surface and Bulk of Spruce Fibers

机译：牛皮纸蒸煮条件对云杉纤维表面和松散化学成分的影响

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摘要

By varying cooking temperature, alkali charge, ionic strength, and cooking time in Kraft pulping of spruce chips, pulps ranging between kappa numbers 20-80 were obtained. The unbleached Kraft pulp fibers were subjected to mechanical peeling in order to separate the surface material from the bulk of the fibers and the carbohydrate composition and lignin content of the two fractions were analyzed. As expected, the lignin and xylan contents were higher on the fiber surface than in the fiber wall. The percentage of xylan on the fiber surface was fairly constant, independent of different pulping conditions or degree of delignification. The lignin proportion on the fiber surface gradually decreased with decreasing kappa number. At a given kappa number, pulping at a higher temperature resulted in less lignin on the fiber surface, probably because of the higher solubility of lignin at higher temperature. Cooking at lower alkali charge also resulted in lower lignin content on the fiber surface at a given kappa number. In this case, there was more time available for degradation of the surface lignin since the lower alkali charge resulted in longer cooking time needed to reach a certain kappa number.
机译：通过改变云杉屑的牛皮纸制浆中的蒸煮温度，碱电荷，离子强度和蒸煮时间，可以获得纸浆的卡伯值在20-80之间。对未漂白的牛皮纸浆纤维进行机械剥离，以使表面材料与大部分纤维分离，并分析了两个馏分的碳水化合物组成和木质素含量。不出所料，纤维表面的木质素和木聚糖含量高于纤维壁中的木质素和木聚糖含量。纤维表面上的木聚糖百分比相当恒定，不受制浆条件或脱木素度的影响。纤维表面上的木质素比例随着kappa值的降低而逐渐降低。在给定的卡伯值下，较高温度下的制浆会使纤维表面的木质素减少，这可能是由于木质素在较高温度下的溶解度较高。在给定的卡伯值下，在较低的碱度下蒸煮还可以降低纤维表面的木质素含量。在这种情况下，由于木质素含量较低，需要更长的烹饪时间才能达到一定的κ值，因此有更多的时间可用于降解表面木质素。

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