Light weight HTPB-clay nanocomposites (HCN) with enhanced ablation performance as inhibition materials for composite propellant

Abstract

In the present study, organically modified Montmorillonite clay with polar moiety, the Cloisite 30B, is used for preparation of Hydroxyl terminated polybutadiene (HTPB)-clay nanocomposites (HCN) by dispersion of nanoclay in polymer matrix under high shear mixing. The nanocomposites thus prepared are evaluated in composite propellants as inhibitor material for their functional utility. Several inhibition formulations containing 5 wt%-15 wt% of nanoclay, with or without the conventional filler Sb2O3, were prepared. All these formulations were evaluated for their physical, mechanical, thermal, and ablative properties. Ablation rate and density of the compositions containing Cloisite 30B is around 23% and 5% lower respectively in comparison of the base composition. Strain capability of these compositions is twofold higher than that of base composition. These compositions have also been evaluated for their smoke generation tendency by measuring infra red (IR) attenuation in the wavelength range 1.3 μm–5.6 μm and 8 μm–13 μm and thereby compared with the base composition. The corresponding results confirmed that the compositions containing Cloisite 30B as filler have much lower IR attenuation than compositions with conventional filler, Sb2O3. Replacement of 5% Sb2O3 by nanoclay showed 8% reduction in IR attenuation rate which further reduced to 16% on replacement of 15% of Sb2O3. Interfacial bonding of HCN based inhibitors is also comparable or even better than conventional inhibitors. Precisely, the nanoclay composites with Cloisite 30B as filler exhibit all desirable properties of an inhibitor.