复合固体推进剂填料/基体脱湿研究进展

概述了复合固体推进剂脱湿的表征方法,分析了各表征方法的优缺点,以及各表征方法适合研究脱湿的范畴,提出了可能的改进方向.概述了各因素对脱湿的影响:内因包括黏合剂基体模量,固体大颗粒含量、粒度、形貌等;外因包括测试温度、拉伸速率、应变率、湿热老化、环境压强等.提出对应的减少各因素影响脱湿发生的方法.     

Mechanical and burning properties of highly loaded composite propellants

An improvement in the performance of solid rocket motors was achieved by increasing the oxidizer content of HTPB-based solid propellants. To minimize the adverse changes in the mechanical and rheological properties due to the increased amount of hard solid particles in the soft polymeric binder matrix, the optimum combination of the particle sizes and volume fractions of the bimodal ammonium perchlorate and the aluminum powder in the solid load was obtained from the results of testing a series of propellant samples prepared by using ammonium perchlorate in four different average particle sizes, 9.22, 31.4, 171, and 323 μm. The maximum packing density of solids in the binder matrix was determined by changing the sizes and the volume fractions of fine and coarse ammonium perchlorate at constant solid loading. The average size (10.4 μm) and concentration of aluminum powder used as metallic fuel were maintained constant for ballistic requirements. Optimum sizes and fine-to-coarse ratio of ammonium perchlorate particles were determined to be at mean diameters of 31.4 and 323 μm and fine-to-coarse ratio of 35/65. Solid content of the propellant was then increased from 75 to 85.6% by volume by using the predetermined optimum sizes and fine to coarse ratio of ammonium perchlorate. Mechanical properties of the propellant samples were measured by using an Instron tester with a crosshead speed of 50 mm/min at 25°C. The effect of oxidizer content and fine-to-coarse ratio of oxidizer on the burning rate of the propellant was also investigated by using a strand burner at various pressures. From experiments in which the size and the fine-to-coarse ratio of ammonium perchlorate were changed at constant solid loading, a minimum value of initial modulus was obtained for each fine-to-coarse ratio, indicating that the solids packing fraction is maximum at this ratio. The tensile strength and the burning rate increase, while the elongation at maximum stress decreases with increasing fine-to-coarse ratio of ammonium perchlorate. Experiments in which the total solid loading was increased at constant fine-to-coarse ratio of ammonium perchlorate show that the modulus, the tensile strength and the burning rate increase, while the elongation at maximum stress decreases with increasing solid loading. Propellants having solid loading of up to 82% exhibit acceptable mechanical properties and improved burning properties suitable for rocket applications. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1457–1464, 1998     

Cross-flow effect on combustion of a solid propellant with harmonically varying pressure

The response function of the burning rate of a solid propellant to periodically varying pressure is found with allowance for the cross-flow (erosion) effect in the linear approximation of the phenomenological theory of nonsteady combustion. Numerical results are obtained for the simplest propellant model with the minimum number of parameters. An elementary acoustic perturbation (planar monochromatic traveling acoustic wave) is considered. The role of steady-state and nonsteady cross-flow components at low and high values of the erosion ratio is elucidated. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 4, pp. 66–72, July–August, 2007.     

固体超强酸SO4^（2-）／Fe2O3／ZnO／ZrO2的制备及其催化合成乙酸异戊酯

以复合固体超强酸SO4^（2-）／Fe2O3／ZnO／ZrO2为催化剂,进行异戊醇和冰乙酸的酯化反应,合成乙酸异戊酯,考察醇酸摩尔配比、反应温度、反应时间、不同焙烧温度催化剂以及催化剂用量等条件对酯化率的影响。结果表明,合成乙酸异戊酯适宜的反应条件是：原料异戊醇与冰乙酸的摩尔配比为2：1,催化剂用量为冰乙酸质量的7％,焙烧温度650℃,120℃反应50min。     

Ignition,combustion, and agglomeration of encapsulated aluminum particles in a composite solid propellant. II. Experimental studies of agglomeration

The combustion characteristics of propellants containing AP, HMX, an energetic binder, and aluminum particles with various polymer coatings are studied at pressures of 0.15 and 4.6 MPa. It is found that the coatings influence the burning rate, the particle size distribution of condensed combustion products, and the completeness of aluminum combustion. It is shown that the agglomeration can be reduced by using aluminum with fluorine-containing coatings. The application of some coatings results in a reduction in the mass of the agglomerates with an insignificant increase in their size. The greatest effect was achieved when using aluminum coated with (CH₂=CH-CH₂-O)₂Si[OCH₂(CF₂-CF₂)₂H]₂ [bis(allyloxy)-bis(2,2,3,3,4,4,5,5-octafluoropentyloxy)silane]. For this coating, a size reduction is also observed for micron-size oxide particles. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 3, pp. 83–97, May–June, 2007.     

Synthesis and characterization of iron carbonyl‐modified hydroxyl‐terminated polybutadiene: A catalyst‐bound propellant binder for burn‐rate augmentation

Iron was coordinately linked to the hydroxyl‐terminated polybutadiene (HTPB) backbone using iron carbonyl via a ligand displacement reaction. The modified HTPB thus obtained was reddish brown in color and was characterized by GPC, FTIR, NMR, thermal, and propellant studies. No significant changes in the rheology, molecular weight, and molecular weight distribution were seen in the modified resin when the bonded Fe content was >0.8.0 wt %. However, the hydroxyl value of the resin decreased by 3–7 irrespective of the weight percent of the bonded Fe, and this was more likely due to the Fe‐catalyzed oxidation of the ? CH₂OH moiety, mostly to the ? CHO group. Apparently, this has not affected the cure characteristics of the binder, as demonstrated by the good mechanical properties of the gum stock and the propellant. The catalytic efficiency of the bonded Fe on the burn rate of the propellant was more efficient than was the free Fe added to the propellant. The aging characteristics of the resin for the bound iron content of ≤0.8 wt % was apparently good, as its viscosity and molecular weight did not undergo any drastic changes even after 18 months' storage under ambient conditions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2813–2823, 2003     

Ignition, combustion, and agglomeration of encapsulated aluminum particles in a composite solid propellant. I. Theoretical study of the ignition and combustion of aluminum with fluorine-containing coatings

This paper gives a brief review of methods for modifying metallic fuels for composite solid propellants, including the application of coatings onto aluminum particles (encapsulation). Requirements for the coating material are formulated. By means of thermodynamic calculations, it is shown that some fluorine-containing coatings reduce the content of the condensed phase in the propellant combustion products without decreasing the specific impulse. A mathematical model for the ignition of a single encapsulated particle is proposed. Calculations show a decrease in the ignition time of an aluminum particle with a fluorine-containing coating. __________ Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 5, pp. 46–55, September–October, 2006.