Challenges in Development of Cellulose Nanocrystal (CNC)-Based Biocomposites

The incorporation of nanoparticles into polymeric matrices has attracted considerable attention, mainly due to the notable improvement of mechanical properties, especially at low levels of filler content. Recently, there has been an increasing tendency towards using Cellulose Nanocrystals (CNCs) as reinforcing fillers combined with polymers. The increase in particular attention could be attributed to the appealing combination of CNCs superior mechanical properties and biodegradability. The use of CNCs as reinforcement agents reveals their capacity to not only improve the strength of materials but also provide environmentally sustainable and biodegradable characteristics to polymer composites. Among the array of various methods available to produce CNC-based nanocomposites, solvent casting and melt processing stand out as the most widely employed techniques. This chapter has mainly focused on PLA/CNC, PBAT/CNC, PLA/PBAT/CNC nanocomposites that are prepared through solution casting, melt mixing or combination of these two methods. The effects of inevitable residual solvent traces on the final properties of solvent-casted nanocomposites and challenges associated with the melt-mixing strategies to produce CNC-based nanocomposites have been reviewed in detail. Moreover, in order to overcome challenges associated with the melt mixing approaches, current status and future perspectives for the use of surface-modified CNCs have been discussed.