Impact of Alkali Treatment on the Internal Microstructure, Surface Topography and the Resulting Mechanical Properties of Single Sisal Fibers

Sisal fibers were extracted and treated in alkali solutions of varying pH concentrations to alter their physical properties for the study. The study explores the effect of the pH concentrations on the internal microstructure using computed tomography, the changes in fibers surface topography using laser confocal microscopy, and how the mechanical properties are affected regarding their surface topography and internal microstructure. The X-ray microscopy scans showed that the untreated fibers are hollow throughout their length, and when treated, these voids collapse and reduce the fibers' diameter. Moreover, this also showed that treatment affects the complete structure of the fiber. Where a pronounced degradation was observed at 25%. This also affects the overall fibers' surface topography and mechanical properties. Where optimal mechanical properties were reported at 1% alkali treatment, this is evidently supported by the change in surface topology at this concentration. This means optimal properties may be achieved at the alkali concentration range below 1% and not necessarily at higher concentrations.