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Open Access Article
1 - A review of the use of rheology in the industry of producing propellants based on nitrocellulose polymer
Mahmoud HeydariOne of the main applications of nitrocellulose polymer is producing propellants. The propellant production process includes mixing nitrocellulose with solvents and other additives and converting it from a fibrous to a non-fibrous state during gelatinization and physical MoreOne of the main applications of nitrocellulose polymer is producing propellants. The propellant production process includes mixing nitrocellulose with solvents and other additives and converting it from a fibrous to a non-fibrous state during gelatinization and physical gel formation. This gel is subsequently subjected to shaping processes using ram or screw extrusion. One of the main problems in producing propellant based on nitrocellulose is the lack of uniformity and product quality control. Despite the high capability of rheology knowledge as a powerful tool for measuring the quality control of raw materials and the production process of propellant based on nitrocellulose, this knowledge has received less attention from researchers and manufacturers in this field. This article reviewed the use of rheology in different parts of the production of nitrocellulose-based propellants, from the quality control of the incoming raw materials to the final mixing and extrusion. At first, the rheological behavior of nitrocellulose mixtures was discussed. Next, the effect of nitrocellulose polymer microstructure on the rheological behavior of its solution was discussed. Phenomena affecting the measurement of the rheological behavior of the mixture, such as wall slippage, were among the other cases investigated. Finally, a review of the quality control methods of nitrocellulose-based propellant products using appropriate material functions and production process modification was discussed. Manuscript profile -
Open Access Article
2 - A review of polymer bonded explosive rheology
Mahmoud HeydariPolymer-bonded explosives are widely used in defense and commercial industries. In this type of explosive, very high amounts of explosive crystals (about 90% by weight) are surrounded by a polymeric binder (about 10%), which leads to a decrease in sensitivity and a sign MorePolymer-bonded explosives are widely used in defense and commercial industries. In this type of explosive, very high amounts of explosive crystals (about 90% by weight) are surrounded by a polymeric binder (about 10%), which leads to a decrease in sensitivity and a significant increase in safety during application and storage. These mixtures are molded in different ways, such as pressing, casting, extrusion, and injection. Studying the rheology of these mixtures with a high percentage of solid loading leads to finding the appropriate quality control method at different production stages. The first step was to review studies on alternatives to simulating explosive rheological behavior, such as dechlorane, calcium carbonate, sugar, etc. The general behavior of simulated mixtures, such as yield stress, shear rate dependence, time dependence, etc., is compared with original explosive. The results showed that despite the similarity in some rheological behaviors, it is impossible to predict and study all the rheological behaviors of polymer-bonded explosives using simulating materials. This paper discusses factors affecting the rheology of polymer-bonded explosives, such as particle size distribution, modification of explosive crystal surfaces, and plasticizer. A review of scientific sources showed that using a wide distribution of explosive crystal particles compared to a narrow distribution led to a significant reduction in viscosity and dependence on shear rate and time. The absence of strong interactions between crystal particles and polymer binder leads to no observation of quasi-solid behavior even in 85% by weight of explosive crystals such as octogen in hydroxyl-terminated polybutadiene Manuscript profile
List of Articles Mahmoud Heydari
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