Six different polymeric matrices were fabricated to reduce the sensitivity of PETN (Pentaerythritol tetranitrate). The polymeric matrices used were individually based on Acrylonitrile butadiene rubber (NBR) softened by plasticizer, styrene-butadiene rubber (SBR) softened by oil, polymethyl methacrylate (PMMA) plasticised by dioctyl adipate (DOA), polydimethylsiloxane (PDMS), polyurethane matrix, and Fluorel binder. A computerised plastograph mixer was utilised for producing three polymer-bonded explosives (PETN-NBR, PETN-SBR, and PETN-PDMS) based on the non-aqueous method. A cast-cured method was used to prepare PBX based on polyurethane (PETN-HTPB), while the slurry technique was used to prepare beads of PETN coated by either fluorel binder (PETN-FL) or based on PMMA forming (PETN-PMMA). The heat of combustion and sensitivities were investigated. The velocity of detonation was measured, while the characteristics of the detonation wave were deduced theoretically by the EXPLO 5 (thermodynamic code). The ballistic mortar experiment was performed to determine the explosive strength. By comparing the results, it was found that PDMS has the highest influence on decreasing the impact sensitivity of PETN, while the cast cured PETN-HTPB has the lowest friction sensitivity. On the other side, PETN-FL has the highest detonation parameters with high impact sensitivity. Several relationships were verified and the matching between the measured results with the calculated ones was confirmed.
In this work, low‐moisture glycidyl azide polymer (GAP) was successfully prepared using a modified two‐step method. The modified method resembles the structure of the classical two‐step method, which is widely used to prepare the GAP. Firstly, epichlorohydrin (ECH) is polymerized into polyepicholorohydrin (PECH), which is subjected afterward to azidation step using sodium azide (NaN3). Interestingly, minimizing the water content in the final GAP product, which is a challenging when dealing with GAP as a rocket propellant binder, was effectively achieved by utilizing low boiling point solvents instead of the relatively high boiling point Dimethyl formamide (DMF), monitoring the volatility of ECH and controlling the exothermicity of the reaction. Prepared GAP samples were investigated using Fourier transformer infra‐red (FT‐IR), gel‐permeation chromatography (GPC) and elemental analysis apparatus (CHNS) were used to characterize the product. The moisture % in the final product was examined using the Karl‐Fisher Technique. Results showed the successful preparation of GAP with low water content (<0.01 %), high average molecular weight (> 2000 g·mol–1), 42.82 % nitrogen, a viscosity of 3484 cP at 20 °C, yield ranges between 95–98 % and a polydispersity index of 1.2. The prepared GAP is promising for replacement of the classical GAPs in the energetic materials applications.
The constant search for protection the soldier during training and participation in hostilities led us to aspire to develop types of energetic materials of a special nature that qualify them to reach the maximum levels of safety during handling, transportation and uses. In this work, we focus on one of these compounds, which is the main component of the preparation of low sensitive compositions. DNAN is an explosive with low sensitivity. Preparation of DNAN in laboratory scale was performed; explosive characterization was presented. Impact and friction sensitivities of DNAN, heat of combustion and detonation velocity were specified. TGA and DSC were used to investigate the DNAN thermal behavior under specific conditions. It was concluded that sensitivity of DNAN is lower than TNT and the chosen cyclic nitramines. The detonation properties of DNAN are slightly lower than TNT however DNAN is candidate individually or with other explosives to replace TNT in low sensitive compositions to full fill the safety and security manipulation of ammunitions.
Three novel high energy dense oxidizers (HEDO), Bis(2,2,2-trinitroethyl)oxalate (BTNEOx), 2,2,2-Trinitroethyl-nitrocarbamate (TNENC), 2,2,2-Trinitroethyl-formate (TNEF) have been prepared and studied as oxidizers in composite solid rocket propellants (CSRPs). For comparison, traditional CSRP containing ammonium perchlorate (AP) bonded by hydroxyl-terminated polybutadiene (HTPB) binder system was studied. The optimum oxidizer percentage with respect to the specific impulse was determined using the thermodynamic code (EXPLO5_V6.03). In addition, the optimum oxidizer mixture based on the novel oxidizers with AP was studied. The combustion properties and gaseous products of the optimum propellant compositions were calculated. A selected composition was prepared in the lab. scale and the burning rate was measured by the strand burner method. It was concluded that TNEF based propellant possess the maximum specific impulse of all the studied compositions. In addition, TNEF based propellant has a higher burning rate than the traditional CSRP composition.
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