A model for predicting tensile modulus of polymer nanocomposites reinforced with cellulose nanocrystals

In this paper, the Young’s modulus of composites containing cellulose nanocrystals (CNCs) is predicted using a simple model. The significance of interphase and CNC dimensions on the nanocomposite modulus was analyzed using the developed model, which was validated using experimental data from a variety of samples. The modulus predictions were in accordance with the measured data, and CNC volume fraction of 0.02 increased the modulus of the system by 65%. Moreover, a nanocomposite that included thinner and longer CNCs had a greater modulus, and the nanocomposite modulus increased by 29.9% when the interphase thickness was 30 nm. Additionally, the modulus of the nanocomposite increased by 35.3% at an interphase modulus of 10 GPa, whereas the modulus of the system increased by 38.4% at an interphase modulus of 60 GPa. Therefore, a thicker and stiffer interphase caused a higher modulus for nanocomposites. Generally, the interphase features and CNC length directly controlled the stiffness of the system, whereas the CNC diameter had an opposite effect.