Application of azide-containing molecules as modifiers of HTPB

Lemos, Maurício Ferrapontoff; Mendes, Luís Claudio; Bohn, Manfred A.; Keicher, Thomas

doi:10.1007/s10973-018-7968-2

Cited by 14 publications

(10 citation statements)

References 35 publications

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“…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. The first ring rupture (a) involved imine formation through proton H 2 transfer; in the second one (b) it was assumed an addition reaction resulting in the aziridine heterocyclic formation.…”

Section: Infrared Evaluationmentioning

confidence: 86%

“…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 4,5dihydro-1,2,3-triazole (triazoline) heterocycle formed through [3 + 2] cycloaddition. [15][16][17][18] Triazoline is unstable and decomposes, releasing nitrogen gas.…”

Section: Infrared Evaluationmentioning

confidence: 99%

“…Results on the chemical compatibility between both substance groups obtained by vacuum stability tests (determining gas generation) and by following the molar mass increase were published by us. 3,4 These findings on compatibility are essential for the prediction of the long-term stability of some developed new binders which considered the presence of azide group in polymer networks together with HTPB or polybutadiene chains. Tanver et al developed an energetic interpenetrating polymer network based on orthogonal azido-alkyne click reaction, and polyurethane for potential solid propellant.…”

Section: Introductionmentioning

confidence: 99%

“…[15][16][17][18] When mixing liquid HTPB with a bifunctionalized azido substance (both azido groups are in one molecule and reachable without sterical hindrance), that is, ethyleneglycol bis-azido-acetate, a solid substance is obtained. On the other hand, a molecule containing only one single azido group reacts with HTPB in producing a viscous liquid with higher molar mass and the HTPB chains contain side chains bonded along the polybutadiene backbone by Ncontaining groups 4 . In our last publication, the formation of imines (C N) was found.…”

Section: Introductionmentioning

confidence: 99%

“…But according to the literature the formation of aziridines is also expected. 4,15 Despite the advantages of HTPB as hydrophobicity, inertness and nonpolar characteristics, it is considered also a drawback for developing new propellants with enhanced ballistic properties, which means high energy content and higher specific impulse. 2,19 The nonpolar characteristic of HTPB limits its compatibility with energetic polar substances and plasticizers.…”

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: Infrared Evaluationmentioning

confidence: 86%

Section: Infrared Evaluationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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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Enzymatic and Chemical Approaches for Post‐Polymerization Modifications of Diene Rubbers: Current state and Perspectives

Soares

Steinbüchel

2021

Macromolecular Bioscience

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Diene rubbers are polymeric materials which present elastic properties and have double bonds in the macromolecular backbone after the polymerization process. Post-polymerization modifications of rubbers can be conducted by enzymatic or chemical methods. Enzymes are environmentally friendly catalysts and with the increasing demand for rubber waste management, biodegradation and biomodifications have become hot topics of research. Some rubbers are renewable materials and are a source of organic molecules, and biodegradation can be conducted to obtain either oligomers or monomers. On the other hand, chemical modifications of rubbers by click-chemistry are important strategies for the creation and combination of new materials. In a way to expand the scope of uses to other non-traditional applications, several and effective modifications can be conducted with diene rubbers. Two groups of efficient tools, enzymatic, and chemical modifications in diene rubbers, are summarized in this review. By analyzing stereochemical and reactivity aspects, the authors also point to some applications perspectives for biodegradation products and to rational modifications of diene rubbers by combining both methodologies.

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Click Chemistry Reactions between Hydroxyl‐Terminated or Alkynyl‐Terminated Polybutadiene and Benzyl Azide

Yang

2021

Propellants Explo Pyrotec

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Alkynyl-terminated polybutadiene (ATPB) may be as a new type of propellant binder through click chemistry reaction between alkynyl and azide group. In this paper, The reactions between ATPB and hydroxyl-terminated polybutadiene (HTPB) with benzyl azide, respecfively, were tracked by 1 H-NMR, 13 C-NMR, FTIR, and Elemental analysis measurements. The results show that the azide group and C=C of HTPB undergo 1,3-dipolar cycloaddition reaction to form a 1,2,3-triazoline ring without the catalyst. Both termi-nal C�C and middle C=C bonds of ATPB can react with azide groups, and the reactivity of the C�C bond is significantly higher than that of the C=C bonds. With the copper (I) catalyst, the reaction between the azide group and the C=C bonds of HTPB is significantly weakened, that is the copper (I) can not catalyze the reaction between C=C and -N 3 . these results are very meaningful for the design of the ATPB and azide system as the binder of solid propellant.

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Application of azide-containing molecules as modifiers of HTPB

Cited by 14 publications

References 35 publications

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

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

Enzymatic and Chemical Approaches for Post‐Polymerization Modifications of Diene Rubbers: Current state and Perspectives

Click Chemistry Reactions between Hydroxyl‐Terminated or Alkynyl‐Terminated Polybutadiene and Benzyl Azide

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