Propellants Explosives Pyrotechnics, Vol.45, No.3, 493-502, 2020
Effects of Aluminum and Temperature on the Tensile Mechanical Properties of Lithium-Perchlorate/Polyvinyl Alcohol-Based Electrically Controlled Solid Propellants
To study the mechanical properties of lithium-perchlorate/polyvinyl alcohol-based aluminized electrically controlled solid propellant (LP/PVA-Al-ECSP), the effects of Al particle size, grading, and content on the mechanical properties of the propellant at various temperatures were investigated. The uniaxial tensile experiments were conducted over the temperature range from -40 degrees C to +50 degrees C using universal testing machine with a crosshead speed of 100 mm min(-1). A scanning electron microscope (SEM) was employed to observe the fracture surface morphologies of the specimens. The results indicate that Al powder and temperature greatly affects the mechanical properties of the composite propellant. From experiments in which the size and the fine-to-coarse ratio of Al were changed at constant solid loading, the tensile strength and initial modulus of the propellant are improved with the increase of Al particle size and coarse-to-fine ratio at 25 degrees C. The increase in Al content improves the tensile strength and initial modulus of the propellant, whereas reduces the elongation. The results of experiments in which the temperature changed indicate that the tensile strength and initial modulus of the propellant are improved at low temperatures, whereas the mechanical properties of the propellants deteriorate at high temperatures. The elongation of the propellants is greatly reduced at low temperatures. The stress-strain curve of ECSP shows three regions at low temperatures and five regions at room temperature and high temperatures. The LP/PVA-Al-ECSP has poor tensile strength and initial modulus, whereas its elongation is extremely high at room temperature. The propellant with 5 mu m Al to 65 mu m Al ratio of 3/7 exhibits the best comprehensive mechanical properties.