Effects of critical interfacial shear modulus between polymer matrix and nanoclay on the effective interphase properties and tensile modulus of nanocomposites

Abstract

Many researchers have investigated the tensile modulus of polymer nanocomposites considering the interphase aspects, but have not considered the minimum interphase modulus that reinforces the nanocomposites. In this research, the critical interfacial shear modulus between polymer and nanoclay (Sc) in nanocomposites is determined mathematically to highlight its effects on the effective interphase properties. In addition, a model for the tensile modulus of polymer clay nanocomposites is developed by considering the clay size, clay morphology, interphase properties, “Sc” and interfacial shear modulus (Si). The predictions of the developed model are compared with experimental data for several samples. Additionally, the model’s calculations for different ranges of all parameters are validated. Good agreement is observed between the calculations and experimental values, validating the accuracy of the proposed model. A poor “Sc” and a high “Si” along with thin and large clay can positively control the efficiency of the interphase region and the modulus of the nanocomposites. A clay thickness (t) of 1 nm and clay length (l) of 11 μm increased the modulus of the polymer matrix by 120%, but for t > 4 nm, or t > 3 nm and l < 4 μm, there was only a 10% improvement in the nanocomposite modulus.