Mercerizing Extraction and Physicochemical Characterizations of Lignocellulosic Fiber from the Leaf Waste of Mikania micrantha Kunth ex HBK

Invasive plants can grow rampantly and spread fast in large amount, which can be economically invoked for generating value-added products. In this study, lignocellulosic fiber was extracted from the leaf waste of a luxuriant invasive plant, Mikania micrantha Kunth-ex H.B.K. by mercerization process. After the alkaline treatment, the lignocellulosic biomass remained at 38.54% resulting from the large removal of extractive impurities. The lignocellulosic fraction in the mercerized leaf fiber was improved from 56.59% to 83.96%. The chemical composition analysis showed the cellulose fraction was increased by 11.17% while the hemicellulose and lignin fractions were found to be decreased by 4.89% and 6.28%, respectively. The FT-IR and TGA results further affirmed the change in chemical composition of the lignocellulosic fiber. Furthermore, an increase in cellulose fraction raised the fiber crystallinity index from 11.0% to 36.7%. The SEM study revealed that the surface morphology of lignocellulosic fiber changed from smooth surface into rough corrugated ridges, which affirmed the increase in crystallinity, resulting from the removal of wrapped cementing materials. In subsequent, the lignocellulosic fiber exhibited more pervious to water attack with an increase in moisture absorption from 119.22% to 410.19%.