الفهرس 
Chapter (1) General introduction and previous workOnly 14 pages are availabe for public view
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Abstract
Polymeric fibers play a vital role as the basis of industrial laboratory, medical industry, and textile industries like, semiconductors, automobiles parts. It became important to study the behaviour of the internal structure at different physical conditions, for example heat treatment and mechanical stretching. This thesis aims to use the online interferometric techniques and diffraction method for studying the opto-viscoelastic properties of isotactic polypropylene fiber at different conditions of annealing. For many years, these techniques have been regarded as a reliable methods for accurate investigation of the variation of the refractive indices, birefringence, crystallinity, density and others isotropic optical properties of fibers. These optical properties are linked with the thermal and viscoelastic properties of fibers. A general introduction and a review of the literature on the fiber characterizations by interferometric methods are presented in chapter (1). Also, a review of the general properties of isotactic polypropylene fibers and their common applications in industry is presented. Chapter (2) gives the description of the basic idea of viscoelasticity and creep behaviour of fibers. The interferometric techniques for multiple-beam and two beam interference systems, and the forward scattering technique are presented. The annealing method which is used as a thermal treatment technique was also presented in this chapter. Theoretical considerations for measuring viscoelasticity, fiber width, refractive index, birefringence and orientation functions are given. The double-arm multiple-beam Fizeau system allows measuring the refractive indices for the case of parallel and perpendicular polarizations, simultaneously. This optical set-up allows the simultaneous recording of two interfererence patterns in the same frame; one pattern for light vibrating parallel to fiber axis, and the other pattern is for perpendicular component of light vibration with respect to the fiber axis. An automated diffraction technique is described in chapter (3) for measuring the effect of annealing on the fiber width statically and during creep process. This method enables one to obtain an online diffraction patterns for fiber at all rotational angels (from 0 - 360o in steps of 20o). This system is useful to detect any irregularity in the fiber width due to the annealing process, and necking deformation. The influence of annealing conditions on viscoelastic properties in terms of creep deformation for isotactic polypropylene (iPP) fiber under a constant load was studied using a modified creep device. Chapter 4 gives the double interferogram pattern which is separated into two independent interference patterns. Those patterns were analysed to give a contour which is used for determining the refractive index, birefringence and crystallinity of the tested fiber. The variation of the refractive indices, birefringence and the optical orientation function f (), was studied at different annealing conditions. Interesting anisotropic-optical properties of isotactic polypropylene fiber were observed. Also, in this chapter, different mechanical deformations, e.g. necking and crazes were observed during the creep process at different annealing conditions.