Structure and Strength-Crystallite Orientation Relationship in Native Cotton Fibres

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">Cotton fibre has a very complex structure at various levels and most of these have not been understood as yet, in spite of considerable efforts put in by innumerable workers, using various physical and allied techniques. Of these, the best efforts have been devoted to understanding the structure of cellulose, which constitutes the bulk of cotton fibre, and the relation between the strength of fibres and the orientation of cellulose crystallites to the fibre axis. In this paper, a review of the most pertinent literature on the structural aspects of cotton fibre is presented; also presented and discussed are data on the physical characteristics and strength-crystallite orientation relationship in respect of a large number of varieties belonging to the <i>Gossypium hirsutum, Gossypium barbadense, Gossypium arboreum </i>and <i>Gossypium herbaceum </i>species of cotton, grown species-wise under identical agroclimatic conditions. This compilation is expected to provide most meaningful comparison of species, varieties and fibre properties and in making a definitive choice about an orientation parameter for varietal characterization of cotton fibres for strength. Such a parameter would be a definitive aid to cotton breeders for a deterministic quality breeding programme and also to cotton fibre technologists for ensuring a uniform quality of finished products. It is concluded from the X-ray diffraction studies on varieties belonging to the four commercial species of cotton that the Hermans crystallite orientation factor is the most reliable index of strength of fibres. Varietal characterization of cotton therefore must be made on the basis of this parameter and not on the basis of 40 or 50% X-ray angles conventionally used.</span>