A precise study on the feasibility of enzyme treatments of a kraft pulp for viscose application
A precise study on the feasibility of enzyme treatments of a kraft pulp for viscose application
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DOI：
10.1007/s10570-010-9483-x
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发表时间：
2011-04-01
期刊：
影响因子：
5.7
通讯作者：
Sixta, Herbert
中科院分区：
文献类型：
--
作者：
Gehmayr, Verena;Schild, Gabriele;Sixta, Herbert
作为提高工艺经济性的工作方案的一部分，研究了将纸级转化为溶解浆的有效工艺步骤的开发。纸浆精制的挑战包括选择性去除半纤维素和精确调节纸浆粘度，同时保持粘胶应用所需的纸浆反应性。本研究的目的是研究各种酶处理对商业氧脱木素蓝桉纸级硫酸盐纸浆在完全无氯漂白过程中的影响，并结合根据改良硫酸盐法蒸煮原理的精炼技术（Sixta等人，2007年）。目的是评估其适用性粘胶纸浆除了减少化学品消耗的碱性和臭氧漂白步骤通过木聚糖酶预处理和控制调整最终纸浆粘度利用内切葡聚糖酶后处理。木聚糖酶预处理与降低碱度的冷碱提取相结合，有效地从纸浆中去除了半纤维素，并通过广泛去除己烯糖醛酸侧链而明显提高了纸浆亮度。木聚糖酶预处理的纸浆表现出增加的反应性对黄原酸和高粘胶原液质量方面的颗粒含量。详细分析了纤维素断链对内切葡聚糖酶浓度的依赖性，这允许精确的粘度降低以及反应性增加。经木聚糖酶预处理和未经木聚糖酶预处理的不同处理的纸浆具有非常窄的分子量分布，并且所纺纤维的质量与来自商业溶解浆的那些粘胶纤维非常相似。
The development of efficient process steps to convert paper-grade to dissolving pulps was investigated as part of the work programme to improve the process economics. The challenge of pulp refinement comprises the selective removal of hemicelluloses and the precise adjustment of the pulp viscosity, while maintaining the reactivity of the pulp as required for viscose application. The purpose of this study was to investigate the effects of various enzyme treatments on a commercial oxygen-delignified Eucalyptus globulus paper-grade kraft pulp in the course of a total chlorine free bleaching sequence in combination with refining techniques following the principle of Modified Kraft Cooking (Sixta et al. 2007). The objectives were to assess its applicability as viscose pulp besides the reduction of chemical consumption in alkaline and ozone bleaching steps by means of xylanase pre-treatment and the controlled adjustment of final pulp viscosity utilizing endoglucanase post-treatment. Xylanase pre-treatment combined with cold caustic extraction at reduced alkalinity efficiently removed the hemicelluloses from the pulp and clearly increased the pulp brightness by extensive removal of hexenuronic acid side chains. The xylanase pre-treated pulp showed increased reactivity towards xanthation and high viscose dope quality in terms of particle content. The dependence of cellulose chain scission on the applied endoglucanase concentration was analyzed in detail, and this allowed precise viscosity reduction as well as reactivity increase. The differently treated pulps, with and without xylanase pre-treatment, were of very narrow molecular weight distribution and the quality of the spun fibers were very similar to those viscose fibers from commercial dissolving pulps.