Nanocellulose-Reinforced “Green” Composite Materials

Abstract

Today, the development of materials has to involve the consideration of environmental responsibility and sustainability. Therefore, more environmentally friendly products, which are biodegradable and derived from renewable resources, have been extensively established. However, in widespread applications, most bio-based polymers when used alone present limitations on their functions and are more costly when compared to their petroleum-based counterparts. One of the most effective ways to enhance the performance of bio-based materials is the incorporation of nanofillers or nanoreinforcements. Recently, cellulose nanofibers or nanocelluloses (NCs) have been paid a great deal of attention to, and incorporated within various biopolymer matrices, since NCs are renewable, biodegradable, carbon neutral, biocompatible, possess extraordinary reinforcing potential, etc. A significant improvement in key performances of the resulting NC-reinforced nanocomposites has been demonstrated, showing that they are comparable, or even better, than the more conventional materials and, thus, are a promising “green” alternative for various applications. Three types of NCs are classified in this review, including microfibrillated cellulose (MFC), cellulose nanowhisker (CNW), and bacterial cellulose (BC), and the NC-reinforced “green” composite systems are overviewed separately for each NC type. The details of their attempted processing techniques, improvements in the nanocomposite properties, dispersion problems in NCs, and remedies are discussed.