Aa. Hamza et al., OPTOTHERMAL PROPERTIES OF FIBERS .2. STRUCTURAL CHARACTERISTICS OF COLD DRAWN ANNEALED EGYPTIAN POLYESTER (PET) FIBERS, Polymer testing, 16(4), 1997, pp. 303-325
Egyptian poly(ethyleneterephthalate) (PET) fibers in the drawn state s
how considerable optical and mechanical anisotropy. The polarizing int
erference microscope is used with a fiber manipulation device to study
, dynamically, the variation of refractive indices and birefringence o
f PET fibers with the draw ratio. In addition, the resulting data were
used to calculate the strain optical coefficient, Poisson's ratio, th
e mean square density fluctuation under different annealing conditions
, as well as several other parameters and constants. Also, an empirica
l formula has been applied to demonstrate the variation of the cross-s
ectional area of PET fibers with draw ratio and the constants of this
formula are determined Microinterferograms are given for illustration.
The change of refractive index profile of annealed PET fibers at diff
erent conditions are also shown. (C) 1997 Elsevier Science Ltd.