Overview of Research Findings on Fiber Structure in Relation to Quality of Egyptian Cottons (G. barbadense L.) <h6 class="resdate">(12/31/1999 20:00)</h6>

Topic One: #

x- ray measurements revealed spiral angle for Egyptian cotton varieties ranging between 31° and 34°. A hypothetical structure was proposed that described spiral angle as a function of fiber length and diameter for different varieties, and diameter and cellulose deposition activity for successive layers of secondary wall within a fiber. Fiber strength depends mainly on spiral angle but modified by the presence of weak points mainly spiral reversals and fiber deformities causing a substantial loss. Tensile strength of single fibers (tested at 10mm test length) varied from 56.8 g/tex for the longest, finest (intrinsically) and of steepest spiral angle Giza 45 variety, to 36.2 g/tex for the shortest, coarsest and widest spiral angle Ashmouni variety. The loss in : tensile strength varied between 6 and 24%, fiber elongation 6 to 13% and work of rupture 11 to 32% Frequency of fiber convolutions was found to be dependent mainly on fiber maturity. Fibers of intermediate maturity exhibit the highest number of convolutions per unit length. As convolutions unfold when the fiber is stretched, they were found to contribute substantially to fiber elongation and work of rupture.

Topic Two: #

Egyptian Cottons were found to possess high levels of luster mainly because of smaller spiral angle, and partly because of smaller diameter and consequently better cross-sectional shape as well as surface smoothness. Also, they are generally of low nep potential. Cotton varieties, however, were found to differ in their tendency to form neps, the greatest part of nep potential is due to production conditions mainly that lead to lower fiber maturity.

Topic Three: #

Egyptian cotton varieties are inherently of very low reducing sugars content, it ranges between 0.21 and 0.33% and between 0.26 and 0.48 for high and medium micronaire reading samples respectively.

Topic Four: #

Fiber quality parameters as looked at by the spinner, and their origin as looked at by the fiber specialist, and accordingly the disciplines or means of change and what should be done to achieve quality improvement have been defined.

By: Mohamed, E. Abdel-Salam
Cotton Research Institute, Giza, Egypt

Submit Date: 12/31/1999 20:00

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