An Apparent Relation Between the Spiral Angle ϕ,the Percent Elongation El,and the Dimensions of the Cotton Fiber

Abstract

A statistical analysis of fiber properties in 56 research cotton samples and 54 primitive rate stocks of Gossypium hirsutum showed that percent elongation E ₁ was positively associated with fiber diameter and negatively associated with fiber wall thickness. These associations were more strongly expressed in the research samples, involving highly selected cotton types, than in the primitive, relatively unselected race stocks. It was show n that E ₁, as measured by the Stelometer, may be a function of ϕ, the spiral angle of the fiber. Estimates of the spiral angle calculated from the E ₁ data gave mean values of 21.99 to 22.41°, which are in close agreement with the "peak" values (22.0 to 22.5°) determined by Morosoff and Ingram using x-ray microcamera photography. Simplistic models of the tubular structure of the cotton fiber were examined to explore the interrelations of variations in spiral angle, elongation, fiber gauge, and wall thickness, and a possible interpretation is presented.