List of Articles رئولوژی

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  1 - A review of the use of rheology in the industry of producing propellants based on nitrocellulose polymer
  Mahmoud Heydari
  One 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 More

  One 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
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  2 - A review of polymer bonded explosive rheology
  Mahmoud Heydari
  Polymer-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 More

  Polymer-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
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  3 - A review of factors influencing the rheological behavior of highly filled composite
  Ali Riazati
  The highly filled composite consists of two polymer matrix components and different fillers with a weight fraction of more than 30% and are widely used in defense systems and aerospace engines. Each of the metal powders can affect the rheological behavior of highly fill More

  The highly filled composite consists of two polymer matrix components and different fillers with a weight fraction of more than 30% and are widely used in defense systems and aerospace engines. Each of the metal powders can affect the rheological behavior of highly filled composites according to their properties, type of granulation, type of particle size, and morphology. The investigation of three types of metal powders, aluminum, magnesium and boron, which are the most used in highly filled composites, has been done in this study. The results of the investigation of the rheological behavior showed that with the increase in the size of solid particles, the content of metal powders, as well as the cross-linking factor, the viscosity and yield stress of the slurry of composite materials increases and causes the flow properties of the slurry to deteriorate and its service life to be shortened. become wet The increase in viscosity is due to smaller solid particles and the increase in molecular weight and the formation of transverse connections in the structure of the prepolymer. The viscosity of the slurry of composite materials decreases with the increase of the shearing speed and shows non-Newtonian pseudo-plastic behavior, and its value depends on the speed and time of the applied shearing force. Combining boron metal powder with magnesium or aluminum powder can greatly improve the rheological behavior of the highly filled composite. Manuscript profile