Effect Of Propellant Drying Characteristic On Mechanical Properties And Research On Single-based Propellant Capillary Rheological Properties

Traditional solvent method is used widely in propellant processing.An on-line auto mass measurement approach was applied to study the volatilization of the residual solvents during the drying process of single-based propellant,TEGDN propellant and modified TEGDN propellant.The drying experiments were conducted under a temperature of 50?,steady humidity and atmospheric pressure.The mechanical properties of propellant strands with different residual solvent contents were tested by a universal testing machine and dynamic mechanical analysis(DMA).Then in order to study the sample surface structure,SEM was used.Also,the rheological properties of single-based propellant were obtained by means of capillary rheometer.The results indicate that the propellant drying rate curve can be divided into three parts:pre-heat,falling rate drying and constant weight period.The simulation of three kinds of propellants drying curve is carried out by exp and poly model.Exp model can be applied for single-based propellant while poly model for other two kinds of propellants.The tensile modulus decreases and elongation at break increases with the increase of the residual solvent content according to the tensile test.Combining the experience,the propellant strands are sufficiently plastic and elastic to be cut without being deformed when they are dried to a certain residual solvent contents of 5.80%-3.6%,9%-5.7%and 9.70%-6.20%.The micro structure of modified TEGDN propellant can be seen with many particles which may lead to stress concentration.Thus,the tensile strength of modified TEGDN propellant is lower than single-based propellant and TEGDN propellant.The TGA curve of three kind of propellants can be used to prove that mechanical properties and drying characteristic only were effected by solvents.It was observed that samples with different solvent contents exhibited a shear-thinning behaviour by capillary.The rise of solvent contents led to the decrement of apparent shear viscosity,while non-Newtonian index n were increased.Thus the dough showed more non-Newtonian property.The results revealed that apparent shear viscosity of samples increased with temperature.The apparent shear viscosity of single-based propellant increased when nano-corrosion inhibitor increasing.In order to improve the flow ability of single-based propellant containing nano-corrosion inhibitor,methods for improving temperature and solvents can be used.