Experimental investigation and micromechanical modeling of high strain rate compressive yield stress of a melt mixing polypropylene organoclay nanocomposites

► Polypropylene based organoclay nanocomposites were tested under high strain rate. ► Micromechanical models were used to predict the yield stress. ► Model predictions are compared to the experimental results and a good agreement is found. In this work, high strain rate compressive yield stress of polypropylene based organoclay nanocomposites has been studied. For this, a three-phase approach is proposed to model the yield behavior of the polymer nanocomposite. This approach is based on the micromechanical formulation of the cooperative model for the yield behavior of semi-crystalline polymers combined with the effect of nanoparticles and their distribution on yielding. In this, our proposed approach accounts for strain rate and temperature effects as well as for the extent of exfoliation of the organoclay fillers. Split Hopkinson pressure bars apparatus was used to carry out high strain rate tests at various temperatures and different strain rates. The experimental results show that the yield stress is strain rate, temperature, and organoclay concentration sensitive. It is also shown that the yield stress is significantly affected by the extent of exfoliation. Our model predictions are compared to the experimental results and a good agreement is found.