Overview of cellulose nanocrystals: Extraction, physicochemical properties and applications

Abstract

The development of cellulose nanocrystal (CNC) has attracted significant attention over the past few decades owing to its unique and superior properties. To date, acid hydrolysis process is still the most frequently used method to treat cellulosic material for the production of CNC. The main reason being that acid hydrolysis method is highly effective in removing the amorphous regions within the cellulose microfibrils while retaining the crystalline domains, thereby yielding CNC. CNC exhibits various outstanding characteristics such as large specific surface area, high aspect ratio, good thermal and mechanical properties, lightweight, high stiffness and high tensile strength. Owing to this, CNC has been subjected into a wide array of research, including implementation as reinforcing agent in nanocomposites and sustainable bio-materials to be utilized in various potential areas of industrial application. Overall, this review summarizes the current knowledge on the isolation, physicochemical properties and applications of CNC.