Assembly of 3-(Tetrazol-5-yl)triazole Complexes with Ammonium Perchlorate for High-Performance Energetic Composites.

Advanced energetic composites possess promising properties and wide-ranging applications in explosives and propellants. Nonetheless, most metal-based energetic composites present significant challenges due to surface oxidation and low-pressure output. This study introduces a facile method to develop energetic composites Cutztr@AP through the intermolecular assembly of nitrogen-rich energetic coordination polymers and high-energy oxidant ammonium perchlorate (AP).

Advanced Al Hydrogel Propellants: Preparation, Thermal Stability, and Self-Sustainable Combustion Characteristics.

A new group of Al-based hydrogel propellants has been prepared and evaluated, aiming to replace currently used Al-ice propellants. The theoretical specific impulse () of these formulations is around 235 s. To enhance the ignition and combustion performances of these propellants, a 2% metastable intermixed composite Al@PVDF-CuO and minor ammonium perchlorate (AP) were introduced.

Reactivity Control of Oxidative CL-20@PVDF Composite Microspheres by Using Carbon Nanomaterials as Catalysts.

2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) is one of the high-energy oxidants, but has limited application due to its high sensitivity. In this work, polyvinylidene fluoride (PVDF) was used as a co-oxidizer, which is expected to increase the safety of CL-20. One kind of novel graphene-based carbohydrazide complex (GCCo and GCNi) was employed to modify the properties of dual-oxidant CL-20@PVDF composites by the spray drying method and compared with traditional nanocarbon materials (CNTs and GO).

Preparation and Reactivity of Core-Shell Al@CL-20 Composites Embedded with Graphene-Based Complexes as Catalysts.

Incomplete combustion of Al in solid propellants can be effectively resolved by coating of an oxidizer at the microscale. In this paper, Al@CL-20 composites with polydopamine as the interfacial layer were prepared using this strategy. The structure, heat of reaction, thermal decomposition properties, and combustion performances of these composites under the effects of graphene oxide (GO) and graphene-based carbohydrazide complexes (GO-CHZ-M, M = Co, Ni) have been comprehensively investigated.

Enhancing the Ignition and Combustion Performances of Solid Propellants Incorporating Al Particles Inside Oxidizers.

The combustion efficiency of Al plays a critical role in the combustion of high-energy aluminum-based solid propellants. For traditional formulations, the Al powders are dispersed in the binder matrix, leading to limited contact with the oxidizers and hence usually insufficient combustion and higher values of the pressure exponent. In this paper, various core-shell structural Al/oxidizer composites such as Al@HMX, Al@AP, and AP@Al have been prepared by a spray-drying technique based on which solid propellants with precise interfacial control between Al particles and oxidizers were realized.

Probing on Mutual Interaction Mechanisms of the Ingredients of Al/CuO/PVDF Nanocomposites.

In this paper, several binary and ternary metastable intermixed nanocomposites Al/CuO, Al/PVDF, CuO/PVDF, and Al/CuO/PVDF have been prepared by simple mechanical mixing and ball milling followed by spray drying methods. In this way, the interfacial structure could be well tuned and compared in terms of reactivity. The nonisothermal DSC curves results showed that the exothermic reaction of Al/CuO/PVDF could be divided into three steps.

Thermal Reactivity of High-Density Hybrid Hexahydro-1,3,5-trinitro-1,3,5-triazine Crystals Prepared by a Microfluidic Crystallization Method.

In this paper, the two-dimensional (2D) high nitrogen triaminoguanidine-glyoxal polymer (TAGP) has been used to dope hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) crystals using a microfluidic crystallization method. A series of constraint TAGP-doped RDX crystals using a microfluidic mixer (so-called controlled qy-RDX) with higher bulk density and better thermal stability have been obtained as a result of the granulometric gradation. The crystal structure and thermal reactivity properties of qy-RDX are largely affected by the mixing speed of the solvent and antisolvent.

Graphene Oxide-Intercalated Tetrazole-Based Coordination Polymers: Thermally Stable Hybrid Energetic Crystals with Enhanced Photosensitivity.

High-energy-density photosensitive pyrotechnics with good thermal stability have been in increasing demand in recent years. In this paper, graphene oxide (GO)-intercalated energetic coordination polymers (ECPs) are prepared with improved thermostability but great photosensitivity by using high nitrogen compounds azotetrazole (AT) and 5,5'-bistetrazole-1,1'-diolate dehydrate (BTO) as ligands. The decomposition activation energy () of Cu-AT has been increased from 135.

Modulation of Crystal Growth of an Energetic Metal-Organic Framework on the Surfaces of Graphene Derivatives for Improved Detonation Performance.

Energetic materials are a special class of energy materials composed of C, H, O, and N. Their safety always deteriorates with increasing energy. Regulating the properties of energetic materials to meet application requirements is one of the focuses of research in this field.

Wireless Rehabilitation Training Sensor Arrays Made with Hot Screen-Imprinted Conductive Hydrogels with a Low Percolation Threshold.

Herein, we propose a highly sensitive wireless rehabilitation training ball with a piezoresistive sensor array for patients with Parkinson's disease (PD). The piezoresistive material is a low percolation threshold conductive hydrogel which is formed with polypyrrole (PPy) nanofibers (NFs) as a conductive filler derived from a polydopamine (PDA) template. The proton acid doping effect and molecular template of PDA are essential for endowing PPy NFs with a high aspect ratio, leading to a low percolation threshold (∼0.

Enhanced thermal and energetic properties of NC-based nanocomposites with silane functionalized GO.

The surface functionalization of graphene oxide (GO) is always attractive in improving certain properties of the polymer. In this study, 3-aminopropyltriethoxysilane (APTES) and 3-mercaptopropyl-trimethoxysilane (SPTES) have been used to make silane functionalized graphene oxides (SiGOs). The APTES-grafted GO (NH-SiGO), SPTES-grafted GO (SH-SiGO) and pure GO have been separately introduced into the nitrocellulose (NC) matrix.

Preparation of CNTs Coated with Polydopamine-Ni Complexes and Their Catalytic Effects on the Decomposition of CL-20.

To improve the condensed-phase reaction rate of ε-CL-20, polydopamine (PDA)-nickel complex-coated multiwalled carbon nanotubes (CNTs) have been prepared and used as combustion catalysts. The PDA-Ni complex has been prepared and coprecipitated with ε-CL-20 by an antisolvent crystallization process in its dimethyl sulfoxide (DMSO) solution. It has been shown that crystalline CL-20 composites included with PDA-Ni complexes are polygon-shaped with a smooth surface and an average diameter of 10-15 μm, whereas it is 140 μm for raw ε-CL-20 crystals.

Hybrid RDX crystals assembled under constraint of 2D materials with largely reduced sensitivity and improved energy density.

In this paper, the widely used energetic material RDX had been modified with 2D high nitrogen polymer (TAGP). Various hybrid RDX crystals (qy-RDX) with higher detonation velocity and better thermostability had been obtained as a result of strong intermolecular interactions between TAGP and RDX molecules. The performance of the qy-RDX had been characterized to clarify the inherent mechanisms.

Gaseous Products Evolution Analyses for Catalytic Decomposition of AP by Graphene-Based Additives.

A quantitative evaluation method has been developed to study the effects of nanoadditives on thermal decomposition mechanisms of energetic compounds using the conventional thermogravimetry coupled with mass spectrometry (TG/MS) technique. The decomposition of ammonium perchlorate (AP) under the effect of several energetic catalysts has been investigated as a demonstration. In particular, these catalysts are transition metal (Cu, Co and Ni) complexes of triaminoguanidine (TAG), using graphene oxide (GO) as dopant.

Transformation of Combustion Nanocatalysts inside Solid Rocket Motor under Various Pressures.

In this paper, the dependences of the morphology, particle sizes, and compositions of the condensed combustion products (CCP) of modified double-base propellants (1,3,5-trimethylenetrinitramine (RDX) as oxidizer) on the chamber pressure (<35 MPa) and nickel inclusion have been evaluated under a practical rocket motor operation. It has been shown that higher pressure results in smaller average particle sizes of the CCPs. The CCPs of Ni-containing propellants have more diverse morphologies, including spherical particles, large layered structures, and small flakes coated on large particles depending on the pressure.

Thermal behavior of graphene oxide and its stabilization effects on transition metal complexes of triaminoguanidine.

The graphene oxide (GO) was found to be able to stabilize organic molecules including energetic compounds. However, the inherent mechanisms of such stabilization effects are still not well-known. Herein, various transition metal complexes of triaminoguanidine nitrate (TAGN) using GO as a dopant have been prepared and evaluated.

Reaction kinetics and a physical model of the charring layer by depositing AlO at ultra-high temperatures.

The thermochemical ablation of insulation material caused by slag deposition in solid rocket motors has increasingly attracted researchers' attention. Understanding the ablation mechanism and the ability to calculate reaction kinetics parameters determine the height of the thermal protection design for advanced solid rocket motors. In this work, the interaction of the AlO-C system is determined through static ablation experiments.

Tuning the Reactivity of Metastable Intermixed Composite n-Al/PTFE by Polydopamine Interfacial Control.

The metastable intermixed composite (MIC) is one of the most popular research topics in the field of energetic materials (EMs). The goal is to invent EMs with tunable reactivity and desired energy content. However, it is very difficult to tune the reactivity of MIC due to its high reactivity and sensitivity caused by enlarged specific surface area and intimate contact between the oxidizers and fuels.

Highly Reactive Metastable Intermixed Composites (MICs): Preparation and Characterization.

Highly reactive metastable intermixed composites (MICs) have attracted much attention in the past decades. The MIC family of materials mainly includes traditional metal-based nanothermites, novel core-shell-structured, 3D ordered macroporous-structured, and ternary nanocomposites. By applying special fabrication approaches, highly reactive MICs with uniformly dispersed reactants, "layer-by-layer" or "core-shell" structures, can be prepared.

Formation of Highly Thermostable Copper-Containing Energetic Coordination Polymers Based on Oxidized Triaminoguanidine.

A series of novel highly thermostable energetic coordination polymers (ECPs), with promising mechanical sensitivity properties, were prepared by an in situ oxidation-coordination reaction of triaminoguanidine hydrochloride with copper nitrate in aqueous solution. The molecular structures and properties of these ECPs could be tuned, by varying the ratios and concentrations of the starting materials. Our ECPs exhibit remarkable thermostability (>390 °C) and very low sensitivity to impact (Im > 98 J).

Highly energetic compositions based on functionalized carbon nanomaterials.

In recent years, research in the field of carbon nanomaterials (CNMs), such as fullerenes, expanded graphite (EG), carbon nanotubes (CNTs), graphene, and graphene oxide (GO), has been widely used in energy storage, electronics, catalysts, and biomaterials, as well as medical applications. Regarding energy storage, one of the most important research directions is the development of CNMs as carriers of energetic components by coating or encapsulation, thus forming safer advanced nanostructures with better performances. Moreover, some CNMs can also be functionalized to become energetic additives.