Study on the Stress Relaxation of Nano Clay-Rubber Nanocomposites Considering Standard Linear Solid Model

Abstract

The effects of nano fillers were studied on the viscoelastic behaviour of NR nanocomposites. Elastic (S’) and viscous (S”) cure torques were larger for higher filler concentration. However, the change in nano clay (NC) content has more effects on S” than S’, comparing with carbon black (CB). Besides, the peak region of S” curve became broader as NC concentration increased and disappeared at 15 phr NC. The effect of CB was clear at concentration above 10 phr, while NC was effective even under 10 phr. Viscoelastic parameters were calculated using standard linear solid (SLS) model and the relaxation curves from SLS model were plotted along with the experimental results. Presence of more amounts of CB and NC led to an increase in the relaxation slope and a higher relaxation modulus at the beginning. In uncured ones, final modulus was near to zero. After curing, initial and final modulus were meaningfully higher. With increasing reinforcement concentration, relaxation time decreased, especially for NC nano filler. Regarding the changes in parameters of model, it was concluded both elastic and viscous motions are considerably more in the presence of higher nano filler levels.