Effect of hard-segment content on rheological properties of glycidyl azide polyol-based energetic thermoplastic polyurethane elastomers

Preparation and Properties of a Novel High-Toughness Solid Propellant Adhesive System Based on Glycidyl Azide Polymer-Energetic Thermoplastic Elastomer/Nitrocellulose/Butyl Nitrate Ethyl Nitramine

Glycidyl azide polymer (GAP)-energetic thermoplastic elastomer (GAP-ETPE) propellants have high development prospects as green solid propellants, but the preparation of GAP-ETPEs with excellent performance is still a challenge. Improving the performance of the adhesive system in a propellant by introducing a plasticizer is an effective approach to increasing the energy and toughness of the propellant. Herein, a novel high-strength solid propellant adhesive system was proposed with GAP-ETPEs as the adhesive skeleton, butyl nitrate ethyl nitramine (Bu-NENA) as the energetic plasticizer, and nitrocellulose (NC) as the reinforcing agent. The effects of the structural factors on its properties were studied. The results showed that the binder system would give the propellant better mechanical and safety properties. The results can provide a reference for the structure design, forming process, and parameter selection of high-performance GAP-based green solid propellants.

Current Self-Healing Binders for Energetic Composite Material Applications

Energetic composite materials (ECMs) are the basic materials of polymer binder explosives and composite solid propellants, which are mainly composed of explosive crystals and binders. During the manufacturing, storage and use of ECMs, the bonding surface is prone to micro/fine cracks or defects caused by external stimuli such as temperature, humidity and impact, affecting the safety and service of ECMs. Therefore, substantial efforts have been devoted to designing suitable self-healing binders aimed at repairing cracks/defects. This review describes the research progress on self-healing binders for ECMs. The structural designs of these strategies to manipulate macro-molecular and/or supramolecular polymers are discussed in detail, and then the implementation of these strategies on ECMs is discussed. However, the reasonable configuration of robust microstructures and effective dynamic exchange are still challenges. Therefore, the prospects for the development of self-healing binders for ECMs are proposed. These critical insights are emphasized to guide the research on developing novel self-healing binders for ECMs in the future.

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. The morphology, thermal properties and energetic properties of the prepared nanocomposites (NH-SiGO and SH-SiGO) were investigated comprehensively. It is shown that the presence of GO and SiGOs have different influences on the thermal reactivity of NC with various contents, and NH-SiGO with 0.5 wt% content showed better catalytic performance on the thermal decomposition of NC than others and showed prominently higher efficiency in improving its heat of combustion. Adding 0.5 wt% of NH-SiGO to NC may decrease its decomposition temperature from 202.1 °C to 196.6 °C, and the residue was decreased from 10.61 wt% to 3.95 wt%, respectively. One isoconversional kinetic method was exploited to determine the kinetic parameters of NC and its nanocomposites. It was found that NH-SiGO had a strong catalytic action on the thermal decomposition of NC-based nanocomposites for which the activation energy and the pre-exponential factor were considerably lowered, while SH-SiGO exhibited an inverse effect. The heat of combustion from NC/GO/0.5, NC/NH-SiGO/0.5 and NC/SH-SiGO/0.5 were determined as 11 249.5, 11 675.1 and 11 491.5 J g^-1, respectively, which are higher than that of the pure NC (10 908.4 J g^-1). From the combustion process of NC/NH-SiGO/0.5, it was shown that the nanocomposite was combusted completely.

Glycidyl azide polymer-based polyurethane vitrimers with disulfide chain extenders

Glycidyl azide polymer-based polyurethane vitrimers were synthesized. By optimizing the parameters, the vitrimers showed decent mechanical properties, healability and reprocessability. Fillers were loaded to synthesize healable composites.

Glycidyl Azide Polymer and its Derivatives-Versatile Binders for Explosives and Pyrotechnics: Tutorial Review of Recent Progress

Glycidyl azide polymer (GAP), an energetic binder, is the focus of this review. We briefly introduce the key properties of this well-known polymer, the difference between energetic and non-energetic binders in propellant and explosive formulations, the fundamentals for producing GAP and its copolymers, as well as for curing GAP using different types of curing agents. We use recent works as examples to illustrate the general approaches to curing GAP and its derivatives, while indicating a number of recently investigated curing agents. Next, we demonstrate that the properties of GAP can be modified either through internal (structural) alterations or through the introduction of external (plasticizers) additives and provide a summary of recent progress in this area, tying it in with studies on the properties of such modifications of GAP. Further on, we discuss relevant works dedicated to the applications of GAP as a binder for propellants and plastic-bonded explosives. Lastly, we indicate other, emerging applications of GAP and provide a summary of its mechanical and energetic properties.