A three-phase micromechanical model for evaluating creep modulus of polymer/Al₂O₃ nanocomposites

In this paper, the creep modulus of polymer/spherical Al2O3 nanoparticle nanocomposites is predicted. An analytical micromechanics model is developed which considers the role of nanoparticle agglomeration and interphase between the nanoparticle and polymer matrix. To show the validity of the micromechanical model, the predictions are compared with the experimental measurements for different nanocomposites. It is found that the creep modulus of the polymer matrix improves by addition of a low content of Al2O3 nanoparticles. However, the nanoparticle agglomeration which may be generated at high content, decreases the creep modulus of nanocomposites. A uniform dispersion of nanoparticles into the polymer matrix is needed to have highest mechanical properties of polymer/Al2O3 nanocomposites. Formation of interphase with higher mechanical properties than the polymer matrix can enhance the nanocomposite creep modulus. By the use of micromechanical model, the effect of elastic modulus and thickness of the interphase between the polymer and nanoparticle on the nanocomposite creep modulus is investigated.