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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.

Raman spectroscopy is an important technique for explosive detection. However, the output spectra are sometimes ambiguous and not strong enough to be analysed. In this work, Surface-Enhanced Raman spectroscopy (SERS) for energetic materials detection was achieved by using in situ impregnated silver nanoparticles in the membrane substrate. The substrates used in SERS were characterised by ultraviolet-visible (UV-vis) spectroscopy and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) for elemental analysis. Three substrates were used, all of which were impregnated with silvernanoparticles. The first substrate (A) received no coating, while the other two substrates (B and C) were coated on one side only with a polymer epoxy layer with a thickness of 0.01 mm and 1 mm, respectively. The three different substrates were used for the detection of an energetic material, TNT, by Raman spectroscopy. The Raman spectrum of TNT using the impregnated substrate without any coating (A) showed an enhancement in the results compared to the epoxy-coated substrates (B and C). Hence, substrate A can be used for energetic materials detection.

Friction stir welding (FSW) is considered to be a solid-state welding technique that is suitable well for joining copper and aluminium sheets. The current experimental study focused on the influence of pin geometry on the micro-structural and mechanical characteristics of such joints. An aluminium sheet was welded to a copper sheet at a constant rotational speed of 1280 rpm and a traverse speed of 16 mm/min. The welding tool was made from W302 steel with four different pin profiles: straight cylindrical, tapered, triangular, and squared. When the squared pin was utilized, the optimum joint was produced as the specimen prepared from this joint had a defectfree structure and a tensile strength of 107.2 MPa (80% of the aluminium strength). On the other hand, the pin with a triangular profile was utilized to determine the minimum characteristics, and the specimens' structures revealed dislocations, separations, and cracking in copper particles inside the aluminium matrix. The microhardness trend is consistent across all specimens. Moreover, specimens welded using squared and cylindrical pin tools have the maximum hardness values obtained at the stir zone of the copper side. The inspection of fractured surfaces showed well mixing between aluminium and copper as well as ductile fracture when a squared pin tool was used while it showed a combination of ductile fracture and brittle fracture for the specimen welded with a triangular pin tool. Based on this study, the use of the squared pin tool gives the most favourable results compared with other pin profiles.

Replacing the inert binder by an energetic one could increase the specific impulse of the propellants and enhance the propulsion characteristics of rockets. In this study, Nitro-b hydroxyl-terminated polybutadiene (NHTPB) was prepared by a simple method. The prepared NHTPB in addition to HTPB binder were characterized. FTIR spectra of both HTBP and NHTPB was determined and compared. The thermal behavior of the prepared NHTPB was studied using DSC technique at heating rate 5 degree/min. A composite propellant based on AP/NHTPB was prepared and the specific impulse was measured for AP/NHTPB using two inch motor. It was concluded that the energetic nitro-hydroxyl-terminated polybutadiene has a clear max. exothermic peak at 203 °C with heat release of 323 J/g. By comparing the results, the prepared propellant AP/NHTPB has specific impulse higher than the traditional AP/HTPB propellant. NHTPB is a promising binder for the application of rocket propellants and needs more tests for its approval.