桑枝Lyocell纤维溶解浆制备及其性能研究

Preparation and Properties of Mulberry Dissolving Pulp for Lyocell Fiber

为探索可再生桑枝资源制备Lyocell级溶解浆的可行性,本研究以桑枝为原料,采用预水解硫酸盐法蒸煮、漂白和酸处理工艺制备了桑枝Lyocell纤维溶解浆。考察了预水解硫酸盐蒸煮、三段漂白(二氧化氯-冷碱抽提-二氧化氯)及酸处理等工艺对溶解浆关键技术指标(α-纤维素含量、聚合度、白度、灰分及金属离子含量)的影响;研究了不同漂白工艺对浆料聚合度和白度的影响;并对溶解浆吸收溶剂速率、纺丝原液流变性能进行分析。结果表明,所得溶解浆的α-纤维素含量92.8%,白度85%,聚合度655,灰分0.09%,铁离子含量4 mg/kg,铜离子含量3 mg/kg,达到Lyocell纤维纺丝用标准。在质量分数50%的NMMO溶液中,90℃抽真空0.05 MPa条件下,制得溶解浆具有良好的溶解性,35 min左右完全溶解。

In order to explore the feasibility of preparing Lyocell grade dissolving pulp from renewable mulberry branch resource,mulberry branch dissolving pulp for Lyocell fiber was prepared by pre-hydrolyzed sulfate cooking,bleaching and acid treatment processes using mulberry branches as raw materials.The effects of pre-hydrolyzed sulfate cooking,chlorine dioxide-cold alkali extraction-chlorine dioxide bleaching and acid treatment on the key technical indexes of dissolved pulp(such asα-cellulose content,degree of polymerization,whiteness,ash content and metal ion content),the effects of different bleaching sequences on the whiteness of pulp polymerization,the solvent absorption rate of pulp and the rheological properties of spinning stock solution were analyzed.The results showed that the dissolving pulp prepared by mulberry branches reached the standard of Lyocell fiber spinning,and theα-cellulose content of the pulp was 92.8%,the whiteness was 85%,the degree of polymerization was 655,the ash content was 0.09%,the iron ion content was 4 mg/kg,and the copper ion content was 3 mg/kg,and it had good solubility under the condition of NMMO solution with mass fraction of 50%and 0.05 MPa vacuum at 90℃.It was completely dissolved in about 35 min.