Adjustable film properties of cellulose nanofiber and cellulose nanocrystal composites

A novel nanocomposite comprised of cellulose nanocrystals (CNCs) and 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) oxidized cellulose nanofibers (TOCNFs) was prepared through solution casting to evaluate potential improvements of the mechanical performance compared to individual reinforcements alone. Such materials can be implemented as mechanical reinforcements in polymer composites, especially when less weight is desired. Dissipative particle dynamics (DPD) simulations, in combination with polarized light microscopy and atomic force microscopy, were analyzed to evaluate the morphology of these combined cellulose nanomaterial (CNM) films. Our results indicate that TOCNFs provide enhanced translational mobility to CNCs which become incorporated near the crystalline domains of TOCNFs. This mobility enables CNCs to increase the rigidity of the network without sacrificing elongation and toughness. The combination of these materials provides improved ultimate tensile strength and elongation without sacrificing the Young's modulus. Therefore, a combination of these materials can be used to develop nanocomposites with enhanced mechanical properties.