Impact of NaOH Treatment on the Chemical, Structural, Physico-mechanical, and Thermal Characteristics of Jute Species

Fiber extracted from two species of jute, Corchorus olitorius (tossa) and Corchorus capsularis (white), is chemically treated with different concentrations (1–6 wt%) of NaOH. Chemical composition, crystallinity, fineness, whiteness, surface morphology, mechanical strength, and thermal stability of both untreated and treated fibers from both jute species are studied. The effects of alkali treatments on the two jute species are characterized using chemical composition analysis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), digital fiber fineness tester, photovoltmeter, universal testing machine (UTM), and thermogravimetric analyzer (TGA). Based on the comprehensive findings, the optimal NaOH treatment concentration was determined to be 5%. The 5% NaOH treatment on both species showed improvements in cellulose content (tossa 13.08%, white 12.88%), crystallinity (tossa 7.81%, white 8.09%), and single fiber strength (tossa 58.61%, white 72.22%). The higher mechanical strength of tossa fiber compared to white jute fiber indicates its potential for composite preparation. On the other hand, the comparatively thinner white jute fiber, when compared to tossa jute fiber, is suitable for blending with cotton or man-made fibers.