Synthesis of 3D Porous Network Nanostructure of Nitrated Bacterial Cellulose Gel with Eminent Heat‐Release, Thermal Decomposition Behaviour and Mechanism

Abstract

In this study, a novel three‐dimensional (3D) porous cross‐link network structure of nitrated bacterial cellulose (NBC) nano‐gel, as an energetic gel matrix for fabrication of nanocomposite energetic materials, (nEMs) was synthesized by sol‐gel synthetic and the freeze‐drying technology. The analysis results revealed that the unique network structure with abundant of nano‐porous, which made the thermal behaviour of the NBC gel different from that of raw NBC. The thermal decomposition kinetic and mechanism of the NBC gel indicated that the exothermic peak temperature of the gel matrix decreased at low concentration, and the activation energy (Ea) of the gel0.5 (150000 J ⋅ mol−1) was much lower than that of raw NBC (223510 J ⋅ mol−1). However, the decomposition kinetic parameters of this study were not enough to illustrate the thermal properties, and which needs more effort to study them and complete. Furthermore, the initial reaction of gel decomposition was the splitting of urethane bond, and then the scission of −O−NO2 bonds happened, and the macromolecular chains’ breakage site of gel first occurred at −C−O−C− in the ring. After then, the chains of NBC break at −C−O−C− between the rings; notably, the heat‐release of gel was several times than that of raw NBC, which was liberated during the process of thermal decomposition. This promising research may provide potential application in preparing binder‐based nEMs and the basic theory of thermo‐analysis used in propellants and explosives.

Cellulose Nitrates-Blended Composites from Bacterial and Plant-Based Celluloses

“…The synthesis of CNs requires that cellulose-concomitant components be removed from plant raw materials, and these processes inflict environmental damage [21]. Research has focused on finding new energetic materials [22][23][24] with a high purity and a unique reticulate nanostructure [25,26] concerning nanocellulose [27][28][29] and, most notably, bacterial cellulose (BC) as the leader among the nanocelluloses [30][31][32], has presently reached its highest demand [33][34][35][36][37]. The broad application prospects and benefits of nanocellulose nitrate-based energetic materials were overviewed back in 2014 [38].…”

“…The initial works on the synthesis of CN from BC (CN BC) were described as early as 2006 [22] and 2010 [23]. The next wave of larger and more extensive studies on CN BC started in 2018 [24] and continues to the present [25][26][27][28][29][30][31][32][33][34][35][36][37] because CN BC has several advantages over plant-based cellulose nitrates, in particular, its high stability due to the ultrafine, high-purity, reticulate fibrous structure.…”

Comparison of the Structure and Thermal Properties of Energetic Binders for Application in Propulsion

“…4 Nevertheless, NC is derived from various plant fibers, which leads to the presence of some impurities, such as lignin, hemicellulose, pectin, starch, and other plant materials. 5 Moreover, it is wellknown that there is a contradiction between the mechanical properties and energy performance of NC. 6 Studies have shown that NC with a higher nitrogen content has higher energy but lower mechanical strength, especially its brittleness feature in low-temperature conditions, which limits the development of high-energy and high-strength propellants.…”

“…In the domain of energetic materials (EMs), energetic binders play a vital role in supporting the energy and mechanical performances of propulsion, such as solid rocket propellants and gun propellants. − Therein, nitrocellulose (NC) is regarded as one of the most significant industrial materials because of its unique physical properties and is widely used in plastics, paints, lacquers, propellants, explosives, and so forth . Nevertheless, NC is derived from various plant fibers, which leads to the presence of some impurities, such as lignin, hemicellulose, pectin, starch, and other plant materials . Moreover, it is well-known that there is a contradiction between the mechanical properties and energy performance of NC .…”

Biomimetic-Inspired One-Step Strategy for Improvement of Interfacial Interactions in Cellulose Nanofibers by Modification of the Surface of Nitramine Explosives

“…In previous works on EMs, scientists have devoted numerous research efforts into investigating the coating additives, for instance, wax, graphite, polymers, , or other insensitive explosives . Typically, polymer materials have always been chosen as binders used in explosive formulations for a long time to enhance the mechanical performances of explosive charges and desensitize the high explosives, which are named plastic-bonded explosives (PBXs). − Therefore, coating DMs on the surface of explosives has been proven to be a useful and effective method to desensitize EMs.…”