ARS | Publication request: Preliminary examination of the effects of relative humidity on the fracture morphology of cotton flat bundles

Submitted to: Textile Research Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 22, 2012
Publication Date: N/A

Interpretive Summary: The effects of the relative humidity of testing conditions on the strength and elongation of cotton fiber were investigated. The effects of moisture in the manner by which cotton fibers break were similarly investigated. Measurements were performed with a stelometer, an instrument that provides reference strength and elongation measurements for small packs of cotton fibers. A trend is observed for stelometer strength and elongations measurements; testing in conditions with higher relative humidity generally resulted in higher strength and elongation values. The morphology of broken fibers was also affected by the humidity in the testing conditions. Fibers broken at high relative humidity showed a more frayed fracture. In contrast, at lower relative humidity fiber fractures were cleaner. Our findings are of relevance to post-harvest moisture control efforts currently employed in the textile industry and may contribute to larger efforts to understand the effects of the fracture and damage observed on cotton fiber properties.

Technical Abstract: The effects of the relative humidity (RH) of testing conditions on stelometer cotton flat bundle strength and elongation measurements, and on the morphology of fiber fractures are presented herein. A trend is observed for stelometer strength and elongations measurements; testing in conditions with higher RH generally resulted in higher strength and elongation values. The morphology of broken fibers was also affected by the testing conditions. Fibers broken at high RH (i.e., 71 ± 2°F and 80 ± 2% RH) showed a more frayed fracture where microfibrils were evident; a fracture pattern that suggests independent microfibril failure. In contrast, at standard conditions (i.e., 70 ± 2°F and 65 ± 2% ) fiber fractures were more granular (clean fractures), a reflection of a more unilateral breaking action. At low RH (i.e., 67 ± 2°F and 50 ± 2%), fiber fractures exhibited a distorted granular pattern, with more persistent surface damage that extended well beyond the fracture location. Our findings are of relevance to post-harvest moisture control efforts currently employed in industry and may contribute to larger efforts to understand the effects of the fracture and damage observed on cotton fiber properties.