Study On The Microstructure And Fracture Mechanism Of Kapok Fiber

Kapok fiber is a kind of environment-friendly natural fiber, which has the quality of light,warm, antibacterial, environmental protection and sound insulation. Because fiber’s torsionalstiffness is bigger, there is more hairiness during the process of spinning, the strength of yarn islower, abrasion resistance is worse. It was used for fill wadding before. Since we concern onenvironmental issues, kapok fiber has become the ideal choice for us. With the improvement andbreakthrough of kapok blended yarn spinning technology and sizing technology, kapok blendedyarn in the application of clothing market has received much attention, and kapok blended textilealso poured into the market. However, some kapok product has the phenomenon of serious hairloss in the using process, what composition of the drop fiber is, what distribution of kapok fibersin the yarn is, what kind of failure forms of kapok fiber in the using process is, whether its failureis related to the structure of kapok fiber, what structure of kapok fiber is t, these problems have notbeen solved. This paper mainly studied the fracture of kapok fiber in the processing and usingprocess, obtained the microstructure and material composition distribution of kapok fiber bychemical treatment, analysed the fracture morphology and fracture mechanism of kapok fiber and.The main research contents and conclusions are as follows:(1) Through the radial distribution of kapok fiber in the yarn and the hairiness comparison ofkapok blended yarn with pure cotton yarn, it was obtained that kapok fiber is easy to transfer tothe outside of blended yarn, the hairiness of kapok blended yarn was more than that of the samelinear density of pure cotton yarn. The number ratio of14.58texkapok/cotton20/80blended yarnand kapok weaving fabric by the yarn was tested and compared, kapok fiber was worn out partlyin high density weaving and the process of dyeing and finishing, especially for the warp yarn, theabrasion volume of kapok was slightly larger. Compared of kapok fiber towel before using withafter using, it was found that the number ratio of kapok fiber washing the face for6weeksdecreased significantly, the amount of losing was much more. The results related to the yarnstructure, kapok fiber was easy to transfer to the outside of yarn in the form of hairiness, it waseasy to wear off.(2) Using different kind of microscope, infrared analysis and alkali treatment, it was foundthat the layer S of kapok fiber existed the structural unit spiral seam line (about8~12microns),and the structure of joint line is loose, which was fiber’s weak link of strength and stiffness. Thestructural unit existed longitudinal stripes, which parallel to the fiber axis and the interval betweentwo adjacent stripes is evener (about0.1microns). The structural unit had smaller and slenderunits, which was composed of cellulose, lignin and hemicellulose, arranged and stacked along thefiber axis. After strong alkali treatment, lignin was dissolved, making layer S of the fiber skindecomposed granular fragments, the shape of the fragments is mostly irregular square. The mainbody of kapok fiber under the epidermis was mainly composed of cellulose. The surface structure of layer W1presented regular weave structure, which was similar to the rough surface of the tree.Layer W1was weaved by smaller and slender unit closely, the slender structure unit was about0.2microns in diameter, the average length was above1.0microns, which had high consistency withthe fiber axis.(3) Observing a series of kapok fibers, it was found it leaved many transverse creases afterwearing and tearing or repeated stress, which was perpendicular to the fiber axis, and kapok fiberfracture likely broke in the crease. Kapok fiber fragment’s length of the quilt’s corner using for sixyears concentrated between255and360microns, which was about7~12times of the diameter ofthe fiber,1/133~1/22of the fiber’s length. The fiber which length was between255and290microns was the most. The length of the fiber fragment was several length of the crease or thespiral seam line. After long-term using, the fracture of kapok fiber was not neat, that was, thefracture was not in a plane, it was showed that the breakage was a gradual process, each small partof the cell wall occurs fracture, until the separation of the second end of the cell. In the process ofdamage, it also can accompany with the process of tearing along the cell wall layer.