Meera Balachandran

MODELING AND OPTIMIZING PROPERTIES OF NANOCLAY-NITRILE RUBBER COMPOSITES USING BOX-BEHNKEN DESIGN

Abstract The mechanical behavior of acrylonitrile butadiene copolymer (NBR)–organomodified layered silicate (nanoclay) was modeled using design of experiments approach. A Box–Behnken design with three factors and three levels was used to model the relationship between properties of NBR nanocomposites and the ingredients. The factors considered in the design were silica content, nanoclay loading, and dicumyl peroxide content. The nanocomposites were evaluated for tensile strength, modulus, elongation at break, oxygen permeation rate, and effect of oil and heat aging 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 as control system ...

Organo-modified layered silicate nanocomposites of EPDM–chlorobutyl rubber blends for enhanced performance in γ radiation and hydrocarbon environment:

In this work, blends of ethylene propylene diene monomer rubber and chlorobutyl rubber were reinforced with organo-modified layered silicate (nanoclay) to enhance their performance in radiation as well as hydrocarbons environments. The mechanical properties of the nanocomposites increased (up to 57%) and solvent transport coefficients decreased (by 30%) with increasing nanoclay content. The enhancement in properties was attributed to the dispersion of nanoclay platelets in the ethylene propylene diene monomer–chlorobutyl rubber blends and the chemical interaction between nanoclay and the polymer which were confirmed by morphological and spectroscopic analysis, respectively. The effect of nanofiller content on the mechanical properties, solvent uptake and thermal degradation of blends exposed to gamma radiation was investigated by irradiating the nanocomposites with gamma rays for cumulative doses of 0.5, 1 and 2 MGy. The ethylene propylene diene monomer–chlorobutyl rubber nanocomposites with 5 phr nanoclay had the best retention of mechanical properties and solvent sorption coefficients on exposure to radiation. Depending on the dose of cumulative radiation exposure, chain scission and/or crosslinking occurred in the nanocomposites, resulting in varying degrees of changes in properties.

Influence of high permittivity nanoparticle on water tree growth in XLPE nanocomposite

The objective of this work is to investigate the influence of high permittivity nanoparticle on resistance to water tree growth in XLPE nanocomposites and indentify their weight percentage for improvement in properties. The nanocomposites based XLPE with suitable nanofillers would be prepared and evaluated for ageing behavior to improve the life of power apparatus used in the high voltage underground power cable insulations. It is proposed to develop simulation models to predict the electrical field distribution and water treeing phenomenon in the nanocomposite using Finite Element method (FEM). Based on the studies, suitable nanofiller or combination of nanofillers and a suitable composition of the nanocomposites would be identified for optimum performance of the insulation. The inception and growth of water trees in the nano dielectrics would be investigated and correlated with the theoretical studies based on simulation.