多种漂白助剂协同下棉短绒浆粕过硫酸氢钾漂白工艺研究

Research on the Bleaching Process of Cotton Linter Pulp with Potassium Peroxymonosulfate Combined with Bleaching Additives

关键词:  精制棉  漂白  过硫酸氢钾  活性物种

Key Words:refined cotton  bleach  potassium peroxymonosulfate  active species

摘要:本研究选用过硫酸氢钾（PMS）为无氯氧化剂对棉短绒浆粕进行漂白研究。在确定工艺组成的基础上通过单因素实验优化工艺条件，成功制备白度超过83%且聚合度保持在2 200左右的精制棉。采用多种表征手段对漂白前后的棉短绒浆粕官能团、晶型和形态进行对比分析。结果表明，PMS漂白过程主要去除纤维素上的有色物质，对纤维本身化学结构的影响较小。漂白助剂焦磷酸钠（PA）、三聚磷酸钠（PB）和十二烷基苯磺酸钠（SDBS）加入后显著提高羟基自由基（·OH）、硫酸根自由基（SO4·-）、超氧自由基（O2·-）和单线态氧（¹O₂）等活性物种的信号强度，使漂白效果明显增强。淬灭O2·-和¹O₂，白度均值降至62.7%、57.8%；淬灭¹O₂，纤维素聚合度均值仍保持在2 742，与未漂棉短绒浆粕相差较小。这表明自由基在漂白过程中起主要作用，其中影响白度的活性物种主要是O2·-和¹O₂，而¹O₂对纤维素的降解作用最大。

Abstract:In this study， an environmental-friendly and high efficiency cotton short linter pulp bleaching process was developed with potassium peroxymonosulfate （PMS） as the major oxidant. Based on determining the process composition， the process conditions were optimized through single-factor experiments， cellulose with the degree of polymerization above 2 200 and the whiteness reached 83% was successfully obtained. Many techniques were performed to measure the functional groups， crystal forms， and morphology of cotton short-staple pulp before and after bleaching. The results showed that the PMS bleaching process could effectively remove the colored substance on the cellulose with less damage to the chemical and crystal structure and morphology of cellulose. In addition， the signal intensity of superoxide radical （O2·-）， singlet oxygen （¹O₂）， hydroxyl radical （·OH）， and sulfate radical （SO4·-） were detected increasing after the addition of sodium diphosphate （PA）， sodium triphosphate （PB）， and sodium dodecylbenzene sulfonate （SDBS） as auxiliaries. The quenching of O2·- and ¹O₂ led the decrease of whiteness decreased by 62.7% and 57.8%， respectively. While the quenching of ¹O₂ made the polymerization degree kept around 2 742. which was not different from the unbleached cotton linter pulp. These results showed that the radicals were involved in the bleaching process， and O2·- and ¹O₂ were the main active species affecting the whiteness of cotton linter pulp， and ¹O₂ had the greastet effect on the polymerization degree of cellulose.