Study On The Degumming Method And Properties Of Hibiscus Bast Fiber

Hibiscus belong to Mallow family, its bast fiber is a new kind of natural cellulose material. In this thesis, chemical composition of the hibiscus bast were analyzed. According to the pectin special properties to do the preprocessing. Adopt a new degumming process to extract the fiber, its properties were tested, and also discuss its utilized value. In this study, the following conclusions were got:(1) Refered to GB 5888-89 "Quantitative chemical composition analysis of Ramie" and tested the hibiscus bast's chemical composition, which include 0.8%-1.8%wax, 9%-12%water-solubles, 4%-7%pectin, 9%-18%hemicellulose, 18%-20%lignin, 45%-55%cellulose, In general, the chemical composition of hibiscus bast was approximate to jute fiber, lignin content in hibiscus bast was very high. In addition, Compared hibiscus bast which were harvested in different periods, the result showed that the best time of harvest is September, and the content of fiber's cellulose can reached to 53.77%(2) Due to the content of hibiscus bast's pectin was high, the twice alkali cooking degumming process was chose. And used the oxidizing action of alkali and hydrogen peroxide to remove lignin in the second cooking process. According to the orthogonal test analysis, the best process parameters were: 8g/L of NaOH concentration, 10g/L of hydrogen peroxide concentration , the first alkali cooking time is 150min.(3) The degummed fiber was existed in the form of bundle. Physical performance was tested, the results were: the average length is around 4-10cm, average density is 37.3dtex, strength is 2.74cN/dtex. Used electron microscopy to observe, its longitudinal section showed flat and strip shape, and have obvious grooves. Its horizontal section showed irregular polygon. And have cracks on the surface of fiber. The X-ray diffraction analysis result showed that the crystallinity of the fiber was 69.05%, the hygroscopicity of hibiscus bast fiber was approximate to jute fiber, and better than ramie.(4) Took alkali modification and cationic modification on the hibiscus bast fiber, the result showed that the dye uptake raised to 16% and 25% respectively after treated. The effect of cationic modification is better.(5) Cut the hibiscus bast fiber to 40mm, used emulsifier to treat them, and then spun them with cotton fiber. The spinning process was air spinning. The result showed that the hibiscus bast fiber has spinnability, and the properties of yarn were good.