Morphological, structural, and thermal properties of cellulose nanocrystals extracted from Indian water chestnut shells (agricultural waste)

The structural and functional similarities of nanocellulose to synthetic polymers have drawn a lot of attention for their use in various applications. This research aimed to isolate the cellulose nanocrystals from Indian water chestnut (locally called Singhara) shells using chemical treatments. The cellulose nanocrystals obtained from the Indian water chestnut shells was characterized to investigate the size, morphology, crystalline structure, chemical functional groups, and thermal stability. The X-ray diffraction analysis indicated that the crystallinity index of cellulose nanocrystals obtained was 65 %. The result revealed that the structure of cellulose nanocrystals is an irregular spherical shape with dimensions in nanometers. Thermogravimetric analysis showed that pure cellulose is more thermally stable than cellulose nanocrystals. These findings reveal the feasibility of using Indian water chestnut shells as raw material to extract nanocellulose crystals. There are many potential areas of application of cellulose nanocrystals. The obtained cellulose nanocrystals may also be found suitable for being used as a reinforcing material in the fabrication of nanocomposites. The commercial usage of Indian water chestnut shells therefore could be increased in manifold ways and the practice of discarding water chestnut shells as agricultural waste can be further reduced.