废旧棉纤维再生过程中纤维素的降聚控制及机理研究

Research on the Depolymerization Control and Mechanism of Cellulose in the Regeneration Process of Waste Cotton Fiber

关键词:  废旧棉  分离回收  蒸煮  降/解聚机理

Key Words:waste cotton  separation and recycling  cooking  reduction/depolymerization mechanism

摘要:针对废旧棉解聚过程中存在的聚合度不可控、杂质含量高、分离难度大，过程污染严重且产品附加值低等问题，本研究开发了蒸煮漂白新体系，探索了废旧棉再生浆粕清洁纺丝新途径，全面研究了各降/解聚产物之间的相互作用原理及调控机制，并对主要成分在降聚过程中的反应机理、转化行为及反应产物的迁移规律进行了系统探索。结果表明，升高蒸煮温度、提高碱浓度、延长蒸煮时间以及增加H₂O₂用量都会加剧纤维的环形剥落和纤维素降解，从而使浆粕的聚合度降低；蒸煮预处理会显著提高废旧棉纤维的结晶度，使棉浆粕中所含有的结合水与非纤维素杂质减少，实现了对棉浆粕中非纤维素杂质的去除。

Abstract:In this study， given the problems in the depolymerization process of waste cotton， such as the uncontrollable polymerization degree， high impurity content， difficult separation， severe process pollution， low-value-added products and so on， a new system of cooking and bleaching was developed and a new way of clean spinning of waste cotton recycled pulp was explored. The interaction principles and regulatory mechanisms among the degradation/depolymerization products were comprehensively investigated， the reaction mechanism， transformation behavior and migration of reaction products of the main components in the depolymerization process were systematically explored. The results showed that increasing the cooking temperature， increasing the alkali concentration， extending the cooking time， and increasing the dosage of hydrogen peroxide could intensify the ring exfoliation of fibers and cellulose degradation， resulting in a decrease in the polymerization of the pulp. The cooking pretreatment could significantly inprove the crystallinity of waste cotton， reduce the bound water and non-cellulose impurities contained in the cotton pulp， and the removal of non-cellulose impurities from the cotton pulp could be realized.