Geometrical and Optical Properties of Irregular Fibers as a Function of Draw Ratio

The Pluta polarizing interference microscope with a fiber rotator-mechanical device was used to detect the variation in the cross-sectional area, shapes and optical properties of irregular fibers during the cold drawing process. The rotation method was used to overcome the difficulty of measuring the transverse cross-sectional area of fibers with irregular shapes during their drawing process. Acrylic fibers of two denier were used during this investigation. Some optical parameters were measured, such as refractive indices and birefringence. The measurements of the refractive indices show that acrylic fibers have a negative birefringence. The polarizability-per-unit volume was used to clarify the negative birefringence of these fibers. Microinterferograms and the digitized images with their contour lines are given for illustration.