| Apocynum Venetum, a wild plant, is regarded as the environment-friendly fiber because no fertilizer is used during growth and it can be degraded biologically. Since apocynum venetum has antibacterial function, good mechanical properties and wearing characteristics, it is also named as 'the king of wild fiber', which can be used to produce popular antibacterial textiles.Although research on mechanical properties of apocynum venetum fibers has been done, there is only a few reports about morphological structure and structure of aggregating state of single fibers till now. The usage of textile materials depends on their performances while the performance relies on their own structures. The morphological structure is a significant factor in determining the spinnability of fibers and properties of products, and the structure of aggregating state works as one of the key factor in determining the characteristics of high polymer. So the morphological structure and the structure of aggregating state of apocynum venetum fibers will be studied in this paper in order to provide theoretical foundation in explaining the performance of apocynum venetum fibers and their products. With the improvement of society, the environmental protection, energy conservation and sustainable development have become even more important in this century. Thus the biological technology has greatly caught people's attention to relieve pollution and energy shortage brought by chemical process industry.Until now, the preliminary treatment on apocynum venetum usually refers to degumming processes of ramie and thus chemical degumming is frequently adapted. But the chemical degumming has some inevitable disadvantages. So in this project, study on the biological degmming has been done and mechanism of the process is discussed from the point of polyoses chemistry and biological dynamics. In spite of the report of antibacterial function of apocynum venetum fibers, the antibacterial efficiency and mechanism of apocynum venetum fibers has not been expressed exactly. In this paper, the performance of antibiosis of apocynum venetum fibers and its mechanism has been studied. The main research work has been done as follows:In the first chapter, the growth, distribution, habit, cultivation techniques and usage of apocynum venetum and performance and development of apocynum venetum fibers and textiles are investigated and summarized. In chapter two, the morphological structure of apocynum venetum fibers are studied by means of optical microscope. On the whole, apocynum venetum fibers are like slight shuttles and clear knots are found on the lengthways surfaces. Different width lumens lie on different places of fibers. Moreover, multiple fibrillar structure of apocynum venetum is researched via TEM to find its primitive fibers have fiberils with bifurcation structure. Crystal structure, orientation and molecular composition of apocynum venetum fibers are also studied with X-ray diffraction, infra-red spectrum, Raman spectrum and DSC.In chapter three, the chemical constitution of apocynum venetum is tested and analyzed in accordance to GB/T5889-1986,《Method for the quantitative analysis of chemical components of ramie》and the results show that the bast fiber of apocynum venetum is different from hemp and ramie and composed of 45% cellulose and 55% non-cellulose components such as semicellulose, lignin, water soluble matter and pectin. It is difficult to achieve good degumming effect due to the high content of non-cellulose in apocynum venetum.Based on the chemical constitution of apocynum venetum and characteristics of gum, the conclusion is drawn that the biological degumming aims to remove pentosan, hexanose, and heteropolymeric polyoses while lignin is difficult to be degraded by the microbe. According to the analysis on the degradation process of gum, the principle of biological degumming is that the gum produces bacterial, bacteria produces enzyme and the enzyme degrades gum. The main approach of degumming is as following: the polyoses gum is hydrolyzed to be pentose and hexose, which is transformed to 6-phosphofructose by HMP and exchange of hexose, and then with the help of EMP, the 6-phosphofructose transforms to acetyl formic acid, which is oxidized to carbon dioxide via tricarboxylic acid cycle and oxidation respiration chain.Factors influencing aerobic biological degumming are also studied and the following factors are involved in experiments: the initial pH value, bath ratio, temperature, time, initial amount of bacterial, ascillation speed, time cultivating liquid bacterial. A series of experiments had been done to analyze how these factors influence bacterial degumming and several crucial factors are picked out via orthogonal test. Through the quadratic general rotary unitized design, the processing parameters of biological degumming are optimized and the optimum parameters are as follows: the degumming temperature is 41～42℃, the initial pH value falls at 8．8, the amount of bacterial is 11．25～12．5mL per gram of apocynum venetum, the ascillation speed is 150r/min and the period cultivating bacterial is 48h with 24h degumming period and 1:25 bath ratio.In the fourth chapter, an investigation into the textile technology with some emphasis on knitting has been reported. The study on the antibacterial properties is also mentioned.Firstly, the antibacterial efficiency of root, stem and leaf of apocynum venetum are measured respectively and the results show that in the same test condition, the root and leaf can kill most of bacteria but the bast has weak bacteriostasis. Reasons of different antibacterial efficiency are analyzed in terms of chemical construction. The phenols and glycoside in root, the phenols and tannis in stem and phenols,β-sitosterol and tannis in leaf mainly contribute to control and kill bacteria. Because of tannis, apocynum venetum fibers have better control on Gram-positive bacteria than Gram-negative bacteria.Secondly, the different proficiencies of apocynum venetum in controlling various bacteria are measured and the results show that apocynum venetum fibers have slight antibacterial effect. Compared with cotton, apocynum venetum can control the growth of bacteria and can kill some of them after a long period. Moreover, apocynum fibers show different antibacterial efficiencies on Gram-positive bacteria and Gram-negative bacteria but they cannot kill fungi. The reasons and mechanism of different antibacterial effects are analyzed from the viewpoint of microbe.At last, apocynum venetum fibers are mixed with cotton fibers with various blending ratios and antibacterial efficiencies of blended yarns of different proportion are tested with different methods and evaluation criterion. The results show that apocynum venetum/cotton yarns hardly have antibacterial function.HAN Guang-ting(Textile Engineering) Supervised by FENG Xun-wei... |
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