Extraction and characterisation of the mechanical properties of cotton stalk bastfibres

Abstract

Cotton stalks are a waste by-product of cotton farming and a problem to dispose of as they tend to harbour parasites such as pink boll worm. The stalks are normally disposed of by burning, which contributes to the emission of harmful greenhouse gases which pollute the environment. Cotton stalks were collected from Umguza region in Zimbabwe which is located 53km from Bulawayo town. The stalks were subjected to retting for 3 weeks and there after fibre extraction carried out by means of manual decortication. The fibres were then subjected to a number of tests such as tensile strength, moisture regain, linear density, density and fibre length measurement test. The fibres were characterised according to their position relative to the cotton stalk and segmented as fibres from the top section, middle section and bottom section. The test results from characterisation of the fibres were analysed using SPSS statistical software. The cotton stalk fibres have a light brownish colour and the fibre length was approximately 8.18cm. The moisture regain of the fibres was highest with fibres extracted from the root area having regain of 11.14%, fibres from the top half had moisture regain of 10.68% and fibres from the bottom half of 10.20%. The diameter of the cotton stalk fibres is 0.23mm which is similar to the diameter found in sisal fibres. The fibres have an elongation of 1.5%. The fibre yield from the cotton stalks is 23%. The cotton stalk fibres have density of approximately 1.45g/cm3.These fibres have possibility in various application which include fibreboards, for wall partitions, furniture applications and ceiling boards to replace solid wood materials.