| Autor: |
R. Sadhana, Elangannan Arunan, Benny K. George, S. Reshmi, C. P. Reghunadhan Nair, K.P. Vijayalakshmi |
| Rok vydání: |
2015 |
| Předmět: |
|
| Zdroj: |
RSC Advances. 5:50478-50482 |
| ISSN: |
2046-2069 |
| DOI: |
10.1039/c5ra03584h |
| Popis: |
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 °C and 78–146 °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). |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
