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Li H.-X.,PLA Second Artillery Engineering University | Qiang H.-F.,PLA Second Artillery Engineering University | Li X.-Q.,PLA Second Artillery Engineering University | Wang H.-W.,The 46th Institute of the Sixth Academy of CASIC
Guti Huojian Jishu/Journal of Solid Rocket Technology | Year: 2012

Aiming at the plasticizer migration in the interface between HTPB propellant and liner, the diffusibility of plasticizer was studied. The diffusion coefficients were obtained by two methods. Firstly, plasticizer diffusivity in the bond system of HTPB propellant was simulated by the molecular dynamics method and the diffusion coefficient was obtained by Einstein equation. Secondly, taking the bonding interface of propellant and thickening liner as the object, the accelerated migration test of plasticizer was performed and the diffusion coefficient was obtained by the second law (Fick). The diffusion coefficients of dioctyl sebacate were discussed under different temperatures and at different contents of plasticizer. It was analyzed that plasticizer migrated by jump on the space situation which were produced when macromolecule chain moved in the HTPB bond system. The results indicated that the magnitude order of DOS diffusion coefficient was 10 -12 m 2/s. The diffusion coefficients gradually increased with increasing of environmental temperature because of more intense activity and larger active space of plasticizer. Yet the diffusion coefficients decreased a little with the increasing of DOS content when content was more than 3%. It is more advantageous to measure diffusion coefficient of plasticizer by molecule dynamics.


Cao F.-Q.,China Airborne Missile Academy | Li X.-H.,China Airborne Missile Academy | Liu Z.-C.,Air Force Military Representative Office in Baotou | Li Y.-L.,The 46th Institute of the Sixth Academy of CASIC | Yun S.,The 46th Institute of the Sixth Academy of CASIC
Hanneng Cailiao/Chinese Journal of Energetic Materials | Year: 2015

In low temperature accelerated aging test method, using maximum tensile strength(σm) and maximum elongation(εm) under uniaxial stretching conditions as aging propellant characteristic parameters, the characteristic changing trend of propellant with different strain level in structural tester at -28℃ was studied. Results indicate that the main reason of the aging of propellant with strain is due to the stress damage under low temperature. The dynamic mechanical analysis (DMA)test validates that the damage of the propellant happenes. The σm of the propellant increases and the εm is waved with time gradually under normal temperature tension tests with the stretching speed of 100 mm·min-1, and the test temperature(23±2)℃. And after 19 weeks low temperature aging, the σm of 15% strain structural tester was increased by nearly 30%. The σm of the propellant increases and εm was decreased greatly with time change under low temperature tension test with stretching rate of 500 mm·min-1and (-55±2)℃. And after 19 weeks low temperature aging, the σm of 15% strain structural tester increases by nearly 11% and the εm decreases by nearly 29%. The ageing mechanism of propellant with strain under low temperature may be physical damage due to the effect of stress or strain, including net cohesion damage and the interface dewetting between solid grains and binder. ©, 2015, Institute of Chemical Materials, China Academy of Engineering Physics. All right reserved.


Chen J.,Science and Technology on Combustion Internal Flow and Thermal Structure Laboratory | Li J.,Science and Technology on Combustion Internal Flow and Thermal Structure Laboratory | Li Q.,Science and Technology on Combustion Internal Flow and Thermal Structure Laboratory | Liu Y.,Science and Technology on Combustion Internal Flow and Thermal Structure Laboratory | And 3 more authors.
Guti Huojian Jishu/Journal of Solid Rocket Technology | Year: 2011

The investigation of carbonized layer structural features and its influence on ablation characteristic of EPDM insulator was carried out under different ablation modes through the ablation test motor, densimeter, scanning electron microscope and micron CT. The results show that the carbonized layer was a typical porous and loose material and a majority of the aperture was opened; Compact/loose structures were formed in carbonized layer of EPDM insulator, which was related with ablation conditions; The erosion resistance of ablatives was improved by the compact structures on the surface. The formation mechanism of compact structures was discussed and a possible cause is that chemical vapor deposition of pyrogenation gas at the specifical temperature. Three typical ablation modes of weak erosion mode, aggradation mode and strong erosion mode were assumed according to the carbonized layer structural features. The conclusion that the erosion resistance of ablatives was improved by the fiber frame could be drawed through the ablation experimental results of different formulation EPDM.

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