scholarly journals Thixotropic Behavior in Defining Particle Packing Density of Highly Filled AP/HTPB-Based Propellant

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1767
Author(s):  
Afni Restasari ◽  
Luthfia Hajar Abdillah ◽  
Retno Ardianingsih ◽  
Hamonangan Rekso Diputro Sitompul ◽  
Rika Suwana Budi ◽  
...  
Keyword(s):  
Packing Density ◽  
Relative Viscosity ◽  
Particle Packing ◽  
Peak Time ◽  
Curing Process ◽  
Stress Growth ◽  
Composite Solid Propellant ◽  
Thixotropic Behavior ◽  
Maximum Particle ◽  
Composite Solid

An alarming, asymmetric flame in rocket combustion originates from a composite solid propellant (CSP) containing defects. The defects are the result of a composition that exceeds the maximum particle packing density. Based on the structure analysis of CSP, the addition of plasticizer causes the correlation between the viscosity of CSP slurry and particle packing density to become uncertain. This work aims to investigate the influence of thixotropic behavior on the maximum particle packing density of CSP. A CSP with different thixotropic behavior was successfully produced using aluminum/plasticizer dioctyl adipate (DOA) of 12–24. During the curing process, viscosity and stress–growth were investigated. The structure of the CSP was defined using X-ray radiography. It is remarkably observed that the peak of thixotropy occurred at the 15th minute of the curing process. The particle packing density of CSP can be decisive for the relative viscosity at the peak time of thixotropic behavior. The CSP with the highest relative viscosity at the peak time was revealed to have voids in the upper part of the CSP. Thus, this parameter was proven to change the preceding parameter, viscosity that was measured at the end of mixing. Based on the stress–growth analysis, it is conceivable that the mechanism involves the time-dependent diffusion of DOA in weakening aluminum agglomerates.

scholarly journals Research on Creep Constitutive and Numerical Simulation of Composite Solid Propellant

2021 ◽  
Vol 1786 (1) ◽  
pp. 012002
Author(s):  
S.X. Feng ◽  
H.F. Qiang ◽  
Y.X. Liu ◽  
X.R. Wang ◽  
T.J. Geng ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Solid Propellant ◽  
Composite Solid Propellant ◽  
Composite Solid

A novel route to improve the mechanical and rheological properties of HTPE/AP/Al propellant by adding a modified hyperbranched polyester

2020 ◽  
pp. 095400832098343
Author(s):  
Xiaomu Wen ◽  
Ximing Zhang ◽  
Keke Chen ◽  
Yunjun Luo
Keyword(s):  
Rheological Properties ◽  
Solid Propellant ◽  
Casting Process ◽  
Hyperbranched Polyester ◽  
Low Viscosity ◽  
Composite Solid Propellant ◽  
Static Tensile ◽  
Void Structure ◽  
Composite Solid ◽  
Hyperbranched Structure

Both better mechanical and rheological properties are pursued for composite solid propellant. In this work, varying proportions of a modified hyperbranched polyester (MHBPE) were added to HTPE/AP/Al propellant. The static tensile property as one kind of mechanical properties of MHBPE/HTPE/AP/Al propellant were found to be superior to those of blank HTPE/AP/Al propellant as a result of the entanglement and interpenetration of molecular chains caused by the introduction of the hyperbranched structure. Evaluations on the related improved creep resistance and stress relaxation performance further demonstrated the advantages of introduction of MHBPE to HTPE/AP/Al propellant. Rheological properties of HTPE/AP/Al propellant with and without MHBPE during the casting process were investigated and compared and the results confirmed the improvement benefiting from low viscosity and loose void structure. Thus, modified hyperbranched polyester provided a novel route to potentially meet the requirements for propellant manufacturing and applications.

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