Cellulose nanocrystals (CNC) were modified via surface grafting of (2-Dodecen-1-yl) succinic anhydride (DDSA) in dimethylformamide (DMF). The resulting DDSA-CNC exhibits good dispersibility in organic solvents with a wide range of polarity. In nanocomposite applications, DDSA-CNC can improve both the dispersion of the nanoparticles in the matrix material as well as the interface between them. For a nanocomposite system containing DDSA-CNC with solvent-based polyurethane (PU), 8.3 vol% CNC could increase the maximum tensile strength and Young's modulus by similar to 125% and similar to 1880%, respectively, and exhibited a 487-fold increase in storage modulus (at 50 degrees C) relative to neat PU. Our results also indicate there is a significant increase in tensile strength and modulus at fairly low CNC volume fractions (e.g., 2.0 and 4.1 vol%) because of the appreciable interactions between DDSA-CNC and PU through the formation of hydrogen bonding. DDSA-CNC reinforced ethylene propylene diene monomer (EPDM) rubber was also investigated for the first time and the properties characterized. (C) 2016 Elsevier Ltd. All rights reserved.