CANCELLED: Stress Relaxation Behavior of Natural Rubber (NR)/Nitrile Rubber (NBR) Blend Nanocomposites

Blends of different polymers have significant influence in industrial applications. Understanding the role of nanofillers in immiscible blends is one of the key factors that researchers put their efforts into. While dealing with the service performance it is necessary to study the time dependent properties like stress relaxation and creep. Here we have prepared different compositions of natural rubber and nitrile rubber blend nanocomposite vulcanazite with different clay loading in an attempt to study the effect of nanoclay on the stress relaxation behavior of these elastomer blends. The effects of clay loading, blend composition, filler polarity, and temperature on stress relaxation were carefully measured. Based on the stress relaxation measurements it was observed that mercapto modified clay is having more affinity towards natural rubber in the blend system. The nature of interaction of the nanoclay was found to influence the stress relaxation rate. Blend nanocomposite with higher filler loading showed higher rate of relaxation rate due to the presence of more number of filler-filler interactions. At 70 ⁰C the viscosity ratio was found to influence the reinforcement and consequently relaxation rate of the 50/50 blend nanocomposite. Polarity of the filler and polymer also was found to influence the stress relaxation behaviour. It was found that the rearrangements of the polymer chains are dependent on the blend composition, temperature, filler/polymer interactions etc. The stretched- exponential Kolrousches equation and three elements Maxwell-Weichert model with three relaxation times were used to model the relaxation behavior and for both models the experimental curve fitted well with the theoretical models.