Meng Chaoran, Li Zhaoling, Wang Chaoyun, Yu Chongwen, Bi Xuerong, Wang Siyi
College of Textiles, Donghua University.
Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences.
J Vis Exp. 2018 Feb 6(132):56461. doi: 10.3791/56461.
This protocol demonstrates a method for ramie fiber extraction by scouring raw ramie in an alkali hydrogen peroxide system supported by a controlled-release alkali source. The fiber extracted from ramie is a type of textile material of great importance. In previous studies, ramie fiber was extracted in an alkali hydrogen peroxide system supported only by sodium hydroxide.However, due to the strong alkalinity of sodium hydroxide, the oxidation reaction speed of hydrogen peroxide was difficult to control and thus resulted in great damage to the treated fiber. In this protocol, a controlled-release alkali source, which is composed of sodium hydroxide and magnesium hydroxide, is used to provide an alkali condition and buffer the pH value of the alkali hydrogen peroxidesystem. The substitution rate of magnesium hydroxide can adjust the pH value of the hydrogen peroxide system and has great influence on the fiber properties. The pH value and oxidation-reduction potential (ORP) value, which represents the oxidation ability of alkali hydrogen peroxide system, were monitored using a pH meter and ORP meter, respectively. The residual hydrogen peroxide content in the alkali hydrogen peroxide system during the extraction process and the chemical oxygen demand (COD) value of wastewater after fiber extraction are tested by KMnO4 titration method. The yield of fiber is measured using a precision electronic balance, and residual gums of fiber are tested by a chemical analysis method. The polymerization degree (PD value) of fiber is tested by an intrinsic viscosity method using the Ubbelohde viscometer. The tensile property of fiber, including tenacity, elongation, and rupture, is measured using a fiber strength instrument. Fourier transform infrared spectroscopy and X-ray diffraction are used to characterize the functional groups and crystal property of fiber. This protocol proves that the controlled-release alkali source can improve the properties of the fiber extracted in an alkali hydrogen peroxide system.
本方案展示了一种在由控释碱源支持的碱性过氧化氢体系中对苎麻原麻进行精练以提取苎麻纤维的方法。从苎麻中提取的纤维是一种非常重要的纺织材料。在先前的研究中，苎麻纤维是仅在由氢氧化钠支持的碱性过氧化氢体系中提取的。然而，由于氢氧化钠的强碱性，过氧化氢的氧化反应速度难以控制，从而对处理后的纤维造成了极大的损伤。在本方案中，由氢氧化钠和氢氧化镁组成的控释碱源用于提供碱性条件并缓冲碱性过氧化氢体系的pH值。氢氧化镁的取代率可以调节过氧化氢体系的pH值，并对纤维性能有很大影响。分别使用pH计和ORP计监测代表碱性过氧化氢体系氧化能力的pH值和氧化还原电位（ORP）值。采用高锰酸钾滴定法测定提取过程中碱性过氧化氢体系中残留的过氧化氢含量以及纤维提取后废水的化学需氧量（COD）值。使用精密电子天平测量纤维的产量，并通过化学分析方法测试纤维的残留胶质。使用乌氏黏度计通过特性黏度法测试纤维的聚合度（PD值）。使用纤维强度仪测量纤维的拉伸性能，包括强度、伸长率和断裂性能。采用傅里叶变换红外光谱和X射线衍射对纤维的官能团和晶体性能进行表征。本方案证明了控释碱源可以改善在碱性过氧化氢体系中提取的纤维的性能。
