Inter molecular azide-diisocyanate coupling: new insights for energetic solid propellants

Reshmi, S and Vijayalakshmi, KP and Sadhana, R and George, BK and Arunan, E and Nair, Reghunadhan CP (2015) Inter molecular azide-diisocyanate coupling: new insights for energetic solid propellants. In: RSC ADVANCES, 5 (62). pp. 50478-50482.

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Abstract

Hydroxyl terminated azide binders can undergo a spurious reaction with diisocyanates to form tetrazoline-5-one via an inter molecular 1,3-dipolar cycloaddition reaction apart from urethane/allophanate groups which has been overlooked. This has serious implications on solid propellants. The computed activation barrier using density functional theory (DFT) for urethane formation reaction is 28.4 kJ mol(-1) and that for tetrazoline-5-one formation reaction is 108.0 kJ mol(-1). DFT studies reveal that the rate limiting step of the reaction is 1,3-dipolar cycloaddition between azide and isocyanate. A dual cure was observed in the temperature ranges 42-77 degrees C and 78-146 degrees C by differential scanning calorimetry (DSC) and rheological studies, confirming multiple reactions. Tetrazoline-5-one formation was confirmed by Fourier transform infrared spectroscopy (FTIR) and solid state nuclear magnetic resonance spectroscopy (NMR).

Item Type:	Journal Article
Publication:	RSC ADVANCES
Publisher:	ROYAL SOC CHEMISTRY
Additional Information:	Copy right for this article belongs to the ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	19 Jul 2015 09:43
Last Modified:	19 Jul 2015 09:43
URI:	http://eprints.iisc.ac.in/id/eprint/51903

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