Preparation of Carboxy Nanocellulose from Waste Shola and its Applications

Ghosh, Snigdha (2025) Preparation of Carboxy Nanocellulose from Waste Shola and its Applications. Masters thesis, Indian Institute of Science Education and Research Kolkata.

Text (MS Dissertation of Snidha Ghosh (20MS162)) 20MS162_Thesis_file.pdf - Submitted Version Restricted to Repository staff only Download (3MB)

Abstract

The study reports the preparation of nanocellulose from waste discarded Shola wood, belonging to Aeschynomene aspera, produced during craft making in a green and scalable approach. Nanocellulose is a nano-scale range of cellulose with exceptional properties, and for these properties, it finds a wide range of applications. In this work, nanocellulose was extracted directly from native Shola wood, a lignocellulosic biomass rich in cellulose (~70%), and a softwood, by only one step without any prior pretreatment, unlike other biomasses using TEMPO-mediated selective oxidative pretreatment with sodium hypochlorite (NaOCl) as the primary oxidant. Additionally, the study reveals the morphological change from fibrous structures to distinct nanospheres (45-80 nm) with the gradual rise in NaOCl concentration, as confirmed by AFM, SEM, TEM, and DLS. This transformation was attributed to enhanced electrostatic repulsion arising from increased surface carboxyl content, quantified via electrostatic repulsion arising from increased surface carboxyl content, quantified via conductometric titration. Characterisations like FTIR, NMR, XPS, and XRD validated effective selective oxidation, preservation of the cellulose backbone’s structure. The oxidized cellulose nanospheres possessed potential functional characteristics, exhibiting high efficiency in the encapsulation of small molecules and a high loading capacity. Further work revealed their capability in stabilizing Pickering emulsions and exhibiting detergent activity. Additionally, surface functionalization involved the loading of azido groups and click-conjugation through a guanidium thiourea linker. In the future, the functionalisation method provides a basis for advanced biomedical and environmental applications. Thus, the Shola, a carbon-neutral plant, can serve as a sustainable source of nanocellulose.

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