Optimizing properties of nanoclay–nitrile rubber (NBR) composites using Face Centred Central Composite Design

The properties of acrylonitrile butadiene copolymer (NBR)–nanoclay composites were modelled using response surface methodology (RSM). A Face Centred Central Composite Design (FCCD) with four factors and three levels was used to obtain the relationship between nanocomposite properties and levels of ingredients. The factors considered in the design were silica content, nanoclay content, vulcanization system and dicumyl peroxide content. The nanocomposites were evaluated for tensile strength, modulus, elongation at break, oxygen permeation rate and effect of oil ageing on mechanical properties. Regression equations were generated to model the properties of interest and generate response surfaces and contour plots. The predicted properties of the nanocomposites were in good agreement with the experimental results. The contour plots were overlaid within the applied constraints to identify the combination of factor ranges that gives the optimal performance of the nanocomposites for application in control system bladders for launch vehicle applications.