Effects of interphase on tensile strength of polymer/CNT nanocomposites by Kelly–Tyson theory

• The effect of interphase between polymer and CNT in polymer/CNT nanocomposites is studied.
• A simple model is developed based on Kelly–Tyson theory for tensile strength of nanocomposites.
• Pukanszky model is combined with the suggested model to calculate various parameters.
• A strong interfacial adhesion between polymer and CNT is sufficient to reduce Lc.

The micromechanics models for composites usually underpredict the tensile strength of polymer nanocomposites. This paper establishes a simple model based on Kelly–Tyson theory for tensile strength of polymer/CNT nanocomposites assuming the effect of interphase between polymer and CNT. In addition, Pukanszky model is joined with the suggested model to calculate the interfacial shear strength (τ), interphase strength (σi) and critical length of CNT (Lc).The proposed approach is applied to calculate τ, σi and Lc for various samples from recent literature. It is revealed that the experimental data are well fitted to calculations by new model which confirm the important effect of interphase on the properties of nanocomposites. Moreover, the derived equations demonstrate that dissimilar correlations are found between τ and B (from Pukanszky model) as well as Lc and B. It is shown that a large B value obtained by strong interfacial adhesion between polymer and CNT is adequate to reduce Lc in polymer/CNT nanocomposites.