Natural Fiber Composition And Morphology Analysis

Currently, common detection method based on the" FZ/T1057.1-2007" to" FZ/T1057.4-2007" is used in fiber identification for quality supervision and inspection departments. Namely uses the combustion method, microscopy and dissolution method for routine testing, combined with the melting point for synthetic fibers testing. In fiber composition analysis, the whole experiment process is cumbersome, time-consuming, and the data repeatability and accuracy are low. Large amounts of toxic and harmful chemical reagents are used in the experimental process, and are harmful to experimental personnel and laboratory environment. Conventional optical microscope is used in fiber morphology analysis, which can not observe the fiber surface morphology in-depth and is likely to cause the analysis error. It is valuable to seek a kind of objective and accurate instrument detection methods for the fiber composition and morphological analysis.The shortcomings of natural fiber component analysis and morphological analysis in quality supervision and inspection departments are discussed based on the experimental data. Pyrolysis gas chromatography/mass spectrometry (PY-GC/MS) technology and electron microscope technology for natural fiber analysis is established in this thesis. The main work and achievements are as follows:Concerning on the quantitative analysis accuracy and repeatability of cotton/regenerated cellulose fiber in the quality supervision and inspection departments, cotton/Lyocell fiber, cotton/Modal fiber, cotton/viscose fiber are chose as representative samples of cotton/regenerated cellulose fibers blend samples, and then using the national standard method for quantitative comparison test. The national standard method for detection posses many steps and system error is unavoidable. The experimental results show that the obtained data is discretion and national standard methods do exist inadequacy as many testing organization reported.The quantitative test results for silk/wool fiber are depended on experimental conditions of the ambient temperature and the dissolution time in the quality supervision and inspection departments with the national standard method. Condition screening, including test temperature and dissolution time, is performed for wool fiber in75%sulfuric acid, with the criterion of D values. The results show that40℃and40min is the best temperature and time of dissolution conditions for silk/wool fiber, in which condition the effect on solubility error is minimal. The experimental results show that to dissolve the wool/silk blend fiber with75%sulfuric acid at room temperature will result in error for different laboratories in different environmental temperature.Pyrolysis gas chromatography/mass spectrometry (PY-GC/MS) technology is employed for determination of natural fiber samples. The pyrolysis products were characterized in-depth and the experimental data show that the main cleavage products of cellulose fibers are very similar, though the content is somewhat difference. However, it is not possible to identify the fiber category only through the cleavage product directly. The cleavage products of protein fiber are characteristics with different content, which could be used for qualitative and quantitative analysis.Because it could not be observed in detail and clear on the fiber surface morphology by traditional optical microscopy in the quality supervision and inspection departments, scanning electron microscope method for natural fiber identification were studied. For the scanning electron microscopy observation of textile fibers, gold target ion sputter coating is used to make the textile fiber conductivity increase. Twice electronic imaging observation is chose as imaging modality to facilitate the observation of the surface.