A simulation study on investigation the optical and structural properties of polyethylene fiber

Multiple-beam Fizeau Interference technique, in transmission, is one of the precise techniques used in the examination of fibers. The modeling equations to simulate multiple-beam Fizeau interferograms, which express the fringe shift or phase modulation of the drawn polyethylene (PE) fibers in the case of using an immersion liquid with a refractive index greater than and less than of PE fiber, were presented. The simulated interferograms were analyzed by our previously published algorithm, which built on the use of the Fourier transform technique for fringe analysis. The simulated interferograms were used to study the effect of the drawing process on the structural properties of PE fibers. Some physical structural parameters, such as the refractive indices, the birefringence, the orientation function, and others, are significantly affected by the drawing process. The density, the degree of crystallinity, the mass fraction crystallinity, the mean square density fluctuation, the molar refractivity, and others are not affected or slightly affected by the drawing process. A new simple approach to determine the isotropic refractive index (μiso) and the principal refractive indices ( μo & μ IIo ) of fully oriented PE fiber is presented. The maximum draw ratio (Dmax) and some constants for PE fiber were obtained. The results obtained are in fair agreement with the published results of PE fiber, which indicates the validity of the simulation equations presented. To illustrate the idea of the work, convenient  interferograms, figures, and tables were presented.