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Rotariu T, Moldovan AE, Toader G, Diacon A, Rusen E, Ginghina RE, Iorga O, Botiș HR, Klapötke T. “Green” PBX Formulations Based on High Explosives (RDX and HMX) and Water-Soluble pH-Sensitive Polymeric Binders. Polymers (Basel) 2023; 15:polym15071790. [PMID: 37050405 PMCID: PMC10098890 DOI: 10.3390/polym15071790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 03/30/2023] [Accepted: 04/01/2023] [Indexed: 04/08/2023] Open
Abstract
The increasingly harsher and more complex international and European environmental legislation drives the current development of “greener” energetics materials and munitions. The aerospace and defense industries rely on extensive research in the formulation and scale-up production of polymer-bonded explosives (PBX). In this context, this paper aims to present a versatile method for obtaining “green” PBX formulations based on two high explosives (hexogen (RDX) and octogen (HMX)) and acrylic acid—ethyl acrylate copolymeric binders. This study developed an innovative “eco-friendly” technology for coating the RDX and HMX crystals, allowing straightforward and safer manufacture of PBX, avoiding the use of traditional organic solvents. At the same time, these polymeric binders are soluble in water at a slightly alkaline pH and insoluble at acidic or neutral pH, thus ensuring a safer manipulation of the energetic materials during their entire life cycle and a facile recovery of the explosive in its original shape and morphology in demilitarization. The PBX formulations were characterized via specific analytical tools to evaluate the influence of their composition on the safety and performance characteristics: scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), alkaline pH solubility tests, differential thermal analysis (DTA), impact sensitivity test (BAM Fall Hammer Test), friction sensitivity test (BAM Friction Test), electrostatic sensitivity test (ESD), vacuum stability test, small scale shock reactivity test (SSRT), detonation velocity test. The “green” PBX formulations obtained through a simple and innovative coating method, based on the polymeric binders’ adjustable water solubility, demonstrated remarkable energetic performances and a facile recovery of the explosive crystals by the dissolution of the polymeric binder at pH 11 and 30 °C.
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Affiliation(s)
- Traian Rotariu
- Military Technical Academy “Ferdinand I”, 39–49 George Cosbuc Boulevard, 050141 Bucharest, Romania
| | - Andreea Elena Moldovan
- Military Technical Academy “Ferdinand I”, 39–49 George Cosbuc Boulevard, 050141 Bucharest, Romania
| | - Gabriela Toader
- Military Technical Academy “Ferdinand I”, 39–49 George Cosbuc Boulevard, 050141 Bucharest, Romania
| | - Aurel Diacon
- Military Technical Academy “Ferdinand I”, 39–49 George Cosbuc Boulevard, 050141 Bucharest, Romania
- Faculty of Chemical Engineering and Biotechnologies, University Politehnica of Bucharest, 1–7 Gh. Polizu Street, 011061 Bucharest, Romania
| | - Edina Rusen
- Faculty of Chemical Engineering and Biotechnologies, University Politehnica of Bucharest, 1–7 Gh. Polizu Street, 011061 Bucharest, Romania
| | - Raluca Elena Ginghina
- Research and Innovation Center for CBRN Defense and Ecology, 225 Olteniţei Ave., 041327 Bucharest, Romania
| | - Ovidiu Iorga
- Research and Innovation Center for CBRN Defense and Ecology, 225 Olteniţei Ave., 041327 Bucharest, Romania
| | - Horia Răzvan Botiș
- Compania Națională ROMARM S.A., 5 Timișoara Boulevard, 061301 Bucharest, Romania
| | - Thomas Klapötke
- Department of Chemistry, Ludwig-Maximilian University of Munich, Butenandtstr. 5–13, 81377 Munich, Germany
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Wang Q, Wang XH, Pan Q, Chang H, Yu HJ, Pang WQ. Thermal Behaviors and Interaction Mechanism of Ammonium Dinitramide with Nitrocellulose. Molecules 2023; 28:molecules28052346. [PMID: 36903591 PMCID: PMC10005589 DOI: 10.3390/molecules28052346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 03/08/2023] Open
Abstract
The initial interaction mechanism is very important for the design and safety of nano-scale composite energetic materials composed of ammonium dinitramide (ADN) and nitrocellulose (NC). The thermal behaviors of ADN, NC and an NC/ADN mixture under different conditions were studied by using differential scanning calorimetry (DSC) with sealed crucibles, an accelerating rate calorimeter (ARC), a self-developed gas pressure measurement instrument and a DSC-thermogravimetry (TG)-quadrupole mass spectroscopy (MS)-Fourier transform infrared spectroscopy (FTIR) combined technique. The results show that the exothermic peak temperature of the NC/ADN mixture shifted forward greatly in both open and closed circumstances compared to those of NC or ADN. After 585.5 min under quasi-adiabatic conditions, the NC/ADN mixture stepped into the self-heating stage at 106.4 °C, which was much less than the initial temperatures of NC or ADN. The significant reduction in net pressure increment of NC, ADN and the NC/ADN mixture under vacuum indicates that ADN initiated the interaction of NC with ADN. Compared to gas products of NC or ADN, two new kinds of oxidative gases O2 and HNO2 appeared for the NC/ADN mixture, while NH3 and aldehyde disappeared. The mixing of NC with ADN did not change the initial decomposition pathway of either, but NC made ADN more inclined to decompose into N2O, which resulted in the formation of oxidative gases O2 and HNO2. The thermal decomposition of ADN dominated the initial thermal decomposition stage of the NC/ADN mixture, followed by the oxidation of NC and the cation of ADN.
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