This paper includes the results of the examination of the single base propellants, double base propellants and double base rocket propellants with the Czech Vacuum Stability Test STABIL. For this method the main term was to analyze and define the best options for preparation of the samples, selection of the optimal mass of the samples and conditions of examination. Chemical stability of these samples was determined according to the STANAG 4556 standard method.

In this study, various technical ceramics in the form of nanostructures, known for their exceptional mechanical properties and thermal resistance, were analysed as potential reinforcement of a polymer matrix system. A combined, hybrid composite matrix was considered, consisting of epoxy resin and polyvinyl butyral. The following nanostructures were incorporated into the polymer matrix by ultrasonication and solvent-casting technique: B4C, TiB2, CNT and INT-WS2. Polymer composites were prepared by solvent-casting of neat hybrid polymer matrix and polymer matrix reinforcing with each chosen individual nanostructure from a temporary solvent – ethanol. The characterisation of the obtained polymer composite samples encompassed Fourier transform infrared spectroscopy analysis, differential scanning calorimetry, tensile test, hardness measurement and examination of resistance to cavitation wear.

Carbon fiber reinforced polymer (CFRP) composites have many applications in civil engineering, aircraft industry and in many other areas. They are lightweight composite materials with outstanding mechanical properties. In this study, the testing specimens were made from the carbon fabrics impregnated with epoxy resin which had been reinforced with the silicon carbide (SiC) microparticles or SiC microfibers. The four-layered composite samples were fabricated by means of hot compression and curing of epoxy resin. The thermal, tensile and impact properties of the untreated specimens were compared with the ones that underwent the water absorption in duration of 72 hours, followed by desorption. The treated specimens containing the SiC particles and SiC microfibers demonstrated 3.4% and 8.8% of the reduction in the tensile energy absorption, correspondingly, compared to their untreated counterparts. Opposed to this trend of results, the tensile energy absorption value of the treated carbon/epoxy specimens, experienced an increase of 84.4% compared to the dry carbon/epoxy specimens. The additional test results showed that the water treated carbon/epoxy composites went into a certain decline in their thermal, tensile and impact properties. The obtained results provide some significant pieces of information for the future practical use of the presented composites. Graphical abstract

Monitoring the chemical stability of gunpowder and double-base rocket propellants is a crucial aspect of quality control for stored ammunition. This intricate undertaking seeks to guarantee the accuracy of ammunition at a satisfactory level, encompassing both its practical functionality and safety considerations. The primary reason for monitoring chemical stability is the presence of nitrocellulose (NC) as the basic energetic component in gunpowder and double-base rocket propellants. This particular form of ammunition, known as NC ammo, undergoes a slow process of degradation over time. It is important to note that even when exposed to normal environmental conditions, it has the potential to ignite spontaneously. This reaction is inherently spontaneous and irreversible, however, it can be slowed down by introducing a small quantity of organic or inorganic substances known as stabilizers. Over time, the stabilizer is gradually consumed, and accurately measuring its quantity is essential for evaluating chemical stability. Aside from stabilizers, additional organic additives are used in nitrocellulose-base energetic materials to enhance performance or streamline the production process. Identification and quantification of organic components are also important from the aspect of analyzing unknown samples. The high-performance liquid chromatography (HPLC) method can be used to determine the content of certain organic compounds. The sample preparation for quantifying the organic compound content relies on the specific type of energetic material being examined, following the standard protocols outlined in the HPLC method. The technique of sample preparation, the equipment needed in the laboratory, and the amount of time required to get accurate and repeatable results are all directly impacted by the solvent selection. This research provides a comparison of sample preparation performances using two different solvents (dichloromethane and acetonitrile) indicating the advantages and disadvantages of both preparation techniques.