Recent Developments in Chemical Derivatization of Microcrystalline Cellulose (MCC): Pre-Treatments, Functionalization, and Applications

Microcrystalline Cellulose (MCC) is an isolated, colloidal crystalline portion of cellulose fibers, and it is a valuable alternative to non-renewable fossil-based materials. It is used for a large plethora of different fields, such as composites, food applications, pharmaceutical and medical developments, and cosmetic and material industries. The interest of MCC has also been driven by its economic value. In the last decade, particular attention has been driven to the functionalization of its hydroxyl groups to expand the field of applications of such biopolymer. Herein, we report and describe several pre-treatment methods that have been developed to increase the accessibility of MCC by breaking its dense structure allowing further functionalization. This review also collects the results that have appeared in the literature during the last two decades on the utilization of functionalized MCC as adsorbents (dyes, heavy metals, and carbon dioxide), flame retardants, reinforcing agents, energetic materials, such as azide- and azidodeoxy-modified, and nitrate-based cellulose and biomedical applications.