A Facile Method to Manufacture the Sesamum Indicum Fibers by Glycolic Acid Assisted with Microwave

The Sesamum indicum bast contains more hemicellulose, lignin, and flaky parenchymal cells than the commonly used ramie bast, which are rigid for the degumming process. We explored a facile and greener method by using glycolic acid microwave-assisted treatment combined with alkaline treatment to effectively and low-cost prepare the high-quality Sesamum indicum single fibers. The chemical and physical properties of fibers were analyzed by chemical composition analysis, SEM, FTIR, XRD, TG, and GPC analysis. The residual gum content was decreased from 34.4% to 4.2%, resulting in a cleaner micro-surface of the Sesamum indicum fibers with increased cellulose crystallinity (75.2%–82.5%) and thermal stability (357°C–365°C). The fiber fineness (2.5 dtex) and breaking tenacity (4.9 cN/dtex) of the fibers produced by the novel treatment method exhibited the same level compared with the traditional two-step alkaline fibers. Besides, both the consumption of water and the chemicals was decreased compared with traditional degumming. This work provided a novel green and facile degumming method for processing the natural bast fibers.相较于常用的苎麻（ramie）韧皮纤维，芝麻（Sesamum indicum）韧皮纤维含有更多的半纤维素（hemicellulose）、木质素（lignin）与片状薄壁细胞，这些组分会给脱胶（degumming）过程带来更高的处理难度。本研究开发了一种简便且绿色的工艺方法，采用乙醇酸（glycolic acid）微波辅助处理结合碱处理，能够高效且低成本地制备高品质芝麻单纤维。通过化学成分分析、扫描电子显微镜（SEM）、傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、热重分析（TG）以及凝胶渗透色谱（GPC）对纤维的理化性能进行了表征。结果表明，纤维残胶率从34.4%降至4.2%，芝麻韧皮纤维的微观表面更为洁净，同时纤维素结晶度提升至75.2%~82.5%，热稳定温度达到357℃~365℃。采用该新型工艺制备的纤维，其纤度（2.5 dtex）与断裂比强度（4.9 cN/dtex）与传统两步碱法纤维处于同一水平。此外，相较于传统脱胶工艺，该方法的水与化学试剂消耗量均有所降低。本研究为天然韧皮纤维的加工提供了一种新型绿色简便的脱胶方法。