The effect of nanoclay on the nonlinear viscoelastic behavior of high‐density polyethylene

Abstract

AbstractThe study's main motivation is to determine the creep behavior of high‐density polyethylene (HDPE)‐based nanocomposites in unexpected situations where short‐term constant loading may occur. On this basis, the short‐term creep behavior of 1 wt.%, 3 wt.%, and 5 wt.% nanoclay reinforced HDPE nanocomposites were investigated at room temperature (23 ± 1°C) and strain rate of 1E‐4 1/s under 8, 12, and 16 MPa stress levels. As the nanoclay reinforcement ratio by weight increased, the creep resistance and modulus of neat HDPE increased at 8 MPa stress level, but they decreased at 12 and 16 MPa stress levels. The absorbed energy that corresponds to the area under the stress–strain curve increase as the stress level increase from 8 to 16 MPa. However, absorbed energy decreases as nanoclay reinforcement increases for 8 MPa. The curves produced from the four‐element Burger's model and Findley's power law models were compared with the creep curves obtained from the experiments. The four‐element Burger model was found to fit the creep curves better than Findley's power‐law model. Also, some regression curves were given for interpolations to give intermediate values of the maximum creep strain values at different stress levels. The presented models can be used to evaluate creep strain, considering the usage fields of parts or semi‐products produced from nanoclay/HDPE nanocomposites.