Macrostructural Changes in Thermally Treated Viscose Fibers Due to Cold Drawwing Process

摘要

The molecular orientation of thermally treated viscose (rayon) fibers was investigated by two techniques. The mechanical parameters, which were obtained by a micro-stress-strian device in conjunction with an interference microscope, and structural parameters, which gave the optical properties, of boiled viscose fibers for different intervals of time and cold drawn at room temperature were calculatied. The changes in the stress and draw ratios were evaluated to to obtain the shrinkage factor, uniaxial tension, and true stress and orientation factors and . The functions f_2(#theta#), f_4(#theta#), and f_6(#theta#) were also calculated. The dielectric constant, dielectric susceptibility, number of moles in physical network chains between entanglements in the semicrystalline phase per unit volume, surface reflectivity, segment anisotropy, nmber of chains between crosslinks per unit volume, and number of crystals per unit volume were among the evaluated parameters. An emirical formula was suggested to correlate the changes inthe evaluated parameters with different draw ratios, and its constants were determined. The study demonstrated changes in the molecular orientation factors and the evaluated macrostructural parameters as a result of applied stress and the boiling effect.