Using The Fractal Theory Of Non-woven Fabric Structure And Transparency

In this thesis, the theory of fractal is applied to non-woven fabric, it is found that the non-woven fabric has statistical and self-similarly character, thus, it has fractal structure. By calculating the fractal dimensions and measuring the permeability of the sample, it is discovered that some regularities exists among the structure, fractal dimensions and permeability of the non-woven fabric.The structure of non-woven fabrics is stochastic, orderless, and very complicated. By far, the character indexes used to evaluate the structure of non-woven fabrics can't express their degree of complexity effectively. Attemption was made to apply fractal theory to study non-woven fabric, because fractal is just the powerful tool to deal with such camplicated problem. The structure of a product is the main part in its quality control. Fractal dimensions can evaluate the non-woven fabrics quantitatively, which will be helpful to increase the degree of accuracy in property of non-woven fabrics, and will be helpful in developing super function and high quality non-woven fabrics.With micro-projector, digital camera and election scanning microscope, the magnified images of non-woven fabrics were obtained, and then input them to computer. The fractal dimensions of several specifications of the non-woven fabric were calculated by using Visual basic program and wavelet algorithm of Matlab. In the meantime, the properties of air ventilation and moisture permeation of some non-woven fabrics were tested.The result of the research indicates that the non-woven fabrics have distinguished character of fractal, their structural fractal dimensions express in a certain sense and the degree of their complex structure.The larger of their structural fractal dimensions, the more disorderly of the fiber, the more complicated of their structure. For the same sort of non-woven fabrics, the larger of the porous fractal dimensions, the better of the permeability.The innovation of the subject lies in several aspects: it applied the theory and method to non-woven fabrics study, put forward fractal dimensions as an index to evaluate non-woven fabrics and made the evaluation more scientific and accurate. The application of fractal theory in non-woven fabrics study has provided theoretical basis in developing super function and high quality non-woven fabrics, which has opened a new pathway in non-woven fabrics researching.