摘要
针对废旧棉织物制备棉浆粕中存在的能耗高和纤维素降解严重等问题,急需开发温和脱色技术实现清洁制浆。采用氢氧化钠-保险粉体系进行废旧棉织物的脱色处理,研究脱色过程中各因素的作用,以及脱色处理对棉织物结构与性能的影响,探究温和脱色机制。结果表明:氢氧化钠可以提升保险粉的稳定性,同时促进棉织物上的染料发生水解扩散到脱色液中;保险粉通过还原作用破坏织物上以及脱色液中染料的发色团,提升染料水解反应程度;在氢氧化钠和保险粉的协效作用下,脱色后棉织物上无染料残留,明度值从16.52提升至70.00以上;脱色处理过程中棉织物的化学结构和结晶结构几乎不受影响,纤维素分子质量及其分布变化不大,脱色棉织物断裂强力保留率在98%以上,不影响后续制浆使用。
Objective It is urgent to adopt the mild decolorization technology for waste cotton fabrics to achieve clean pulping to resolve the problems that the high consumptions of energy,as well as severe degradation of cellulose during preparation of cotton pulp from waste cotton fabrics.Method Due to the violent reaction when decolorizing cotton fabric with oxidant,the breaking strength of the decolorized cotton fabric is lost more,and the molecular chain is broken seriously.While the reaction when decolorizing cotton fabric with reductant is relatively mild.A method for decolorizing was conducted to black mercerized cotton fabric,named as the sodium hydroxide-sodium hydrosulfite system through orthogonal experiment and single factor experiment.The role of decolorization parameters,influence of decolorization treatment on the structure and properties of cotton fabrics and mild decolorization mechanism were investigated.Results Sodium hydroxide can improve the stability of sodium hydrosulfite(Fig.1),and can hydrolyze and destroy the covalent bond between reactive dyes and black mercerized cotton fabric,so that the dyes on cotton fabric can hydrolyze and diffuse into the decolorization solution(Fig.2).At the same time,the dye chromophore group on the cotton fabric and in the solution will be destroyed under the reduction of sodium hydrosulfite(Fig.3).Because sodium hydrosulfite itself will undergo invalid decomposition,sodium hydrosulfite is added in a two-step process decomposes more active substances for decolorization and shorten the time of decolorization reaction(Fig.5 and Fig.6),and the lightness value of the decolorized cotton fabric is increased from 16.52 to above 70.00 by adopting the best two-step decolorization process.Almost no dye remains on the cotton fibers under the synergistic effect of sodium hydroxide and insurance powder(Fig.7).The decolorization system has been proved to be able to reduce the strength loss of the cotton fabric after bleaching,and the break strength retention rate of the cotton fabric
作者
王伟
吴嘉欣
张晓云
张传杰
宫兆庆
WANG Wei;WU Jiaxin;ZHANG Xiaoyun;ZHANG Chuanjie;GONG Zhaoqing(College of Textiles&Clothing,Qingdao University,Qingdao,Shandong 266071,China;Weihai Innovation Institute,Qingdao University,Weihai,Shandong 264200,China;Weihai Key Laboratory of Functional Textile Auxiliaries,Weihai,Shandong 264500,China)
出处
《纺织学报》
EI
CAS
CSCD
北大核心
2023年第7期175-183,共9页
Journal of Textile Research
基金
国家重点研发计划项目(2020YFC1910301)。
关键词
废旧棉织物
脱色机制
氢氧化钠
保险粉
浆粕
温和脱色技术
waste cotton fabric
decolorization mechanism
sodium hydroxide
sodium hydrosulfite
pulp
mild decolorization technology
