Mechanical, thermal and ablative behavior of organo nanoclay added carbon fiber/cyanate ester resin composites and effect of heat flux on its ablative performance

Abstract

Nanoclay added cyanate ester resin (Type I) composites were fabricated by adding different weight percentages (0,1,2,4 & 6 wt%) of organo-modified Montmorillonite (o-MMT) and tested for dispersion by Small angle X-ray scattering(SAXS), thermal stability using Thermogravimetric analyser (TGA) and curing behavior using Differential scanning calorimeter (DSC). This data was correlated with the thermomechanical properties of nanoclay added carbon fiber reinforced cyanate ester resin composites (C-CE composites /Type II). Interlaminar shear strength (ILSS), flexural strength of type II composites increased by about17%, 21% respectively at 2 wt% addition of nanoclay although at this loading nanoclay was found to show intercalation.Thermal stability of type II composites got reduced whereas the ablation rate has increased for type II composites with increased loading of nanoclay. However, percentage increase in ablation rate was found to be lower when type II composites were tested at 5000 kWm−2as compared to the ablation testing carried out at 1250 kWm−2. Scanning electron microscopy studies indicates significant melting of nanoclay at high flux resulting in additional protection mechanisms for the composites at high flux. Present study indicates the possibility of using o-MMT nanoclay for improved mechanical properties of C-CE composites used in thermal protection systems (TPS).