“…Nanocellulose is an “ageless” biomass nanomaterial with at least one nanoscale dimension, known as the mechanical building block of cellulose-containing species. Basically, nanocellulose can be divided into two families, viz ., rigid and highly crystalline cellulose nanocrystals (CNCs) and semiflexible cellulose nanofibrils (CNFs) depending on their different production processes. , Endowed with numerous properties, such as renewability, good biocompatibility, nontoxicity, active surface chemistry, and low density but high mechanical modulus, nanocellulose is being developed for a broad range of applications from functional additives in composites, packaging, coating, construction, food industry, and cosmetics to body materials in papermaking, energy storage, filtration, and biomedical materials. , Average values of around 130 and 100 GPa are reported for the longitudinal modulus of CNCs and CNFs, respectively, with a low density for crystalline cellulose of about 1.5–1.6 g cm –3 , which is similar to the commercial reinforcing agent Kevlar (60–125 GPa, 1.45 g cm –3 ) and potentially stronger than steel (200–220 GPa, 8 g cm –3 ) . The impressive specific modulus and high aspect ratio of nanocellulose make it an ideal candidate as a reinforcing filler for composites, which has been widely studied in various polymeric matrices, including natural polymers as well as polar and nonpolar synthetic polymers. − …”