Energetic Materials Laboratory
Department of Chemistry
Indian Institute of Technology Kanpur, India
Dr. Srinivas Dharavath
Our research group will design and synthesize various nitrogen-rich azoles, fused and strained rings containing small molecules which are highly dense, thermally stable, and insensitive towards mechanical stimuli for 'Green' and 'Environmentally friendly' high energy materials (HEM) applications. So far, we have synthesized various poly-nitrogen containing small energetic molecules and salts from commercially available cheap starting materials as HEMs in a simple and straightforward manner. Few synthesized molecules are a better replacement for the existing benchmark energetic materials that meet the requirements of present and future civil, defense, and space applications.
Design and synthesis of high-performing energetic materials
In material science, high energy materials (HEMs) are among the most essential functional substances and are widely utilized for various military and civilian purposes. HEMs are designed to store enormous amounts of energy in the chemical structure in a condensed phase releasing rapidly (in the case of an explosive) or gradually (in the case of propellants) and exerting abrupt change in heat-pressure on the surroundings. Since the discovery of black powder and the subsequent development of nitroglycerine, nitrocellulose, TNT, TATB, RDX, HMX, CL-20, etc., the demand for new materials has increased with desired properties for civil, defence, and space exploration programs.
HEMs with specific and modifiable physicochemical and energetic properties are essential for their precise applications. New HEMs with tunable performance and safety have been the subject of an extensive investigation by researchers worldwide. Some of the present challenges in the field of HEMs are (i) Demand for green energetic materials with nitrogen-rich heterocyclic backbone as a replacement for TNT, RDX and HMX since they produce an enormous amount of toxic gases (CO and CO2) on detonation. (ii) Insensitivity towards heat, impact, friction, and electrostatic discharge is an essential and fate-deciding parameter for HEMs. (iii) Development of higher-performing melt-castable ingredients that are more energetic than TNT and DNAN. (iv) Combining high performance with less sensitivity i.e., minimizing energy-safety contradiction.
The heterocyclic backbone plays an excellent role in the design and synthesis of HEMs. Developing new and convenient synthetic routes, high energy-safety balance, and environmentally benign nature has tremendous value to the wider materials community.
Dr. Srinivas Dharavath
Poly tetrazole containing thermally stable and insensitive alkali metals-based 3D energetic Metal-Organic Frameworks (EMOFs)
Poly tetrazole containing thermally stable and insensitive alkali metal-based 3D energetic
metal-organic frameworks (EMOFs) are promising high energy density materials to balance
the sensitivity, stability, and detonation performance of explosives in defense, space, and
civilian applications. Herein, the self-assembly of L3- ligand with alkali metals Na(I) and K(I)
were prepared at ambient conditions, introducing two new EMOFs, [Na3(L)3(H2O)6]n (1) and
[K3(L)3(H2O)3]n (2). Single crystal analysis reveals that Na-MOF (1) exhibited a 3D wave-
like supramolecular structure with significant hydrogen bonding among the layers while K-
MOF (2) also featured as a 3D framework. Both the EMOFs were thoroughly characterized
by NMR, IR, and TGA/DSC analyses. Compounds 1 and 2 show excellent thermal
decomposition Td = 344 and 337 than the presently used benchmark explosives RDX°C °C
(210 ), HMX (279 ) and HNS (318 ) which attributed to structural reinforcement°C °C °C
induced by extensive coordination. They also show remarkable detonation performance
(VOD = 8500 m s-1, 7320 m s-1, DP = 26.74 GPa, 20 GPa for 1 and 2, respectively) and
insensitivity towards impact and friction (IS ≥ 40 J, FS ≥ 360 N for 1; IS ≥ 40 J, FS ≥ 360 N
for 2). Their excellent synthetic feasibility and energetic performance suggest that they are
the perfect blend for the replacement of present benchmark explosives such as HNS, RDX,
Design and computational studies on energetic compounds composing bridged bis triazolo-triazine framework
Density functional theory was used to design a new series of bridged (directly connected, –CH=CH–, –CH2–, –CH2–CH2–, –O–, –NH–, –NH–NH–, –N=N–) energetic compounds based on bis[1,2,4]triazolo[4,3-b:4',3'-d][1,2,4]triazine (bis triazolo-triazine) backbone with explosophoric functionalities (–NO2, –NHNO2, and –NH2 groups). Using the predicted densities and heats of formation in Kamlet-Jacobs equations, detonation performance was assessed, which specify that the –NO2 group is a suitable explosophore for enhancing performance. Comparing the influence of different linkages on detonation properties it is observed that –O–, –NH–, and –N=N– linkages are more beneficial for enhancing performance. The bond dissociation energy (BDE), heat of detonation (Q), balance parameter (ν), and impact sensitivity (h50) values were utilized to determine stability and sensitivity. Some designed bis triazolo-triazine molecules have high densities (>1.85 g/cm3) and good detonation performance (VOD > 8.40 km/s and DP > 32 GPa), may be considered as the potential energetic material candidates.