Small Rings by Azide Chemistry

Gilchrist, T. L.; Alves, M. I. Caetano

doi:10.1002/9780470682517.ch6

Cited by 4 publications

(6 citation statements)

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“…Triazoline is unstable and decomposes, releasing nitrogen gas. Herein the proposed reaction mechanism is revised, based on infrared and nuclear magnetic resonance evaluations and with the help of other published results 15,26,27 . Unlike the mechanism previously proposed in, 4 four different paths are shown in Figure 3 for the rupture of the triazoline ring.…”

Section: Resultsmentioning

confidence: 95%

“…Recently, we published an article suggesting a reaction mechanism between azido‐containing molecules and the HTPB double bonds generating imines and aziridines groups 4 . According to studies on organic azides and cycloaddition, the reaction starts by an intermediary 4,5‐dihydro‐1,2,3‐triazole (triazoline) heterocycle formed through [3 + 2] cycloaddition 15‐18 . Triazoline is unstable and decomposes, releasing nitrogen gas.…”

Section: Resultsmentioning

confidence: 99%

“…The mixture of a polymer chain containing double bonds with azido groups containing polymers or just molecules cannot be stable over time since they are reactive against each other. Reaction mechanisms between alkenes and azides are already reported elsewhere 15–18 …”

Section: Introductionmentioning

confidence: 96%

“…In our last publication, the formation of imines (CN) was found. But according to the literature the formation of aziridines is also expected 4,15 …”

Section: Introductionmentioning

confidence: 99%

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On the functionalization and characterization of hydroxyl‐terminated polybutadiene with octyl‐1‐azide and the evaluation of polyurethane elastomers based on such modified HTPB

Lemos

Mendes

Bohn

2020

J of Applied Polymer Sci

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Hydroxyl-terminated polybutadiene (HTPB) has been modified with azidocontaining substances to be applied in propulsion systems. Pristine HTPB has compatibility issues with energetic polar substances and plasticizers, which is a drawback to develop new high-energy propellants. This work presents a path for the functionalization of HTPB, carried out through a controlled bulk reaction of it with octyl-1-azide. Then it was reacted with isophorone diisocyanate with or without dioctyl adipate (DOA). Structural, thermal, rheological, and dynamic-mechanical assessments were accomplished. Infrared revealed the arising of absorption bands associated to the C N stretching. From 13 C and 1 H nuclear magnetic resonances, it is possible to deduce the presence of amine, aziridine, and imine chemical groups, which may promote compatibilization with other polar and energetic substances. The chemical modification induced an increase of viscosity. With respect to the glass-liquid and glass-rubber transitions, the modification shifted them slightly to higher temperatures, but created stiffer networks, in agreement with the increase of polarity and chain interaction due to the presence of N-containing functionalities. Regarding the solid elastomer binder, the storage shear modulus and molecular mobility were influenced by the type of HTPB and DOA content. In general, the modified HTPB has physical properties like pristine HTPB.

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

“…In our last publication, the formation of imines (CN) was found. But according to the literature the formation of aziridines is also expected 4,15 …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations