Extraction and characterization of cellulose nanocrystals from cotton fiber by enzymatic hydrolysis‐assisted high‐pressure homogenization

Cellulose nanocrystals (CNCs) have attracted increasing attention in the field of nanomaterials because of its high aspect ratio, good structure, and high thermal stability. In this study, enzymatic hydrolysis‐assisted high‐pressure homogenization was applied as an environmentally friendly technique to extract CNCs from cotton‐derived microcrystalline cellulose (MCC). The overall optimization of enzymatic pretreatment was conducted by response surface methodology, and the maximum CNCs yield was 40.09% under the optimized experimental conditions. The extracted CNCs under the optimal conditions showed needle‐like shape with a length of 100–250 nm and a width of 5–10 nm and exhibited an overall particle size range of 3–80 nm. The basic chemical structure of cellulose was not changed after enzymatic hydrolysis and high‐pressure homogenization. The CNCs exhibited slightly lower crystallinity and higher thermal stability than MCC. High aspect ratio CNCs extracted in this present study have great potential as a reinforcing agent in biodegradable packaging materials.