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2 Central European Journal of Energetic Materials

2 2021

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Review of Nano-thermites: a Pathway to Enhanced Energetic Materials

Zaky Mohamed Gaber, Elbeih Ahmed, Elshenawy Tamer

Central European Journal of Energetic Materials

2021

Vol. 18, no. 1

63--85

Nano-thermites or metastable intermolecular composites (MICs) have been implemented into modern research on energetic materials as they offer much higher energy densities, higher rates of energy release, stability, and safety (lower sensitivity). This paper reviews several synthetic methods for MICs that have been well thought-out for energetic applications, advantages and disadvantages, as well as the characteristics of each manufacturing technique. The techniques presented include powder mixing, sol-gel, synthesis of MICs based on nano-porous silicon (Psi), sputtering, multilayer nano-foils and electrolytically plated carbon nano-materials for nano-thermite applications. These techniques offer enormously different characteristics and, through the variation of various chemical techniques and conditions, a wide range of chemical and energetic properties may be attained. This may give the opportunity for the safe use of MICs as replacements for some conventional energetic materials in various applications, and may also enable us to study the effects when incorporating these MICs into energetic matrixes, as a promising and feasible research field.

Novel Composite Solid Propellant with High Resistance to Thermo-oxidative Degradation Reactions, Extended Shelf Life, and Superior Combustion Characteristics

Elbasuney Sherif, Elsaka Eslam, Elbeih Ahmed, Mostafa Hosam E.

Central European Journal of Energetic Materials

2021

Vol. 18, no. 1

143--158

Hydroxy-terminated polybutadiene (HTPB) pre-polymer is the main constituent that is responsible for conferring high mechanical properties on composite solid propellants. However, HTPB pre-polymer suffers from oxidative degradation reactions that diminish its mechanical properties and shelf life. Composite solid propellant formulations based on an advanced stabilizing agent (anti-oxidant), Flexzone 6-H, with different curing ratios, 0.7 and 1.1, were developed via mixing and casting under vacuum. The developed formulations were subjected to artificial ageing using Vant Hoff,s formula by isothermal heating at 80 °C for up to 35 days. The change in strain with ageing was evaluated using a uni-axial tensile test. The propellant formulation based on a curing ratio of 0.7 demonstrated a high ageing resistance coefficient and an extended service life of up to 15 years, compared with 5 years for higher curing ratio. A propellant grain is considered to be ‘aged out’ at 30% reduction in its maximum strain value. The propellant formulation based on the 0.7 curing ratio exhibited superior thermal stability as it offered a minimum decrease in heat released after ageing using DSC. Additionally, the 0.7 curing ratio formulations exhibited a minimum change in burning rate and pressure exponent with ageing time. It can be concluded that the propellant with 0.7 curing ratio can maintain its mechanical, thermal, and ballistic properties with ageing.