The casting of an Ammonium Perchlorate (AP)/Hydroxyl-Terminated Polybutadiene (HTPB) concentrated suspension is one of the important processes in the preparation of AP/HTPB composite propellant. In this study, the flow characteristics of an AP/HTPB concentrated suepension were investigated experimentally. The results obtained are as follows: 1) The relationship between relative viscosity and volume fraction of AP can be shown by Mori-Ototake equation. k and φ_vc, constants in the Mori-Ototake equation are obtained as a function of the void fraction (ε_max) in a loosely packed bed of AP powders. 2) In order to prepare an AP/HTPB suspension which has a low enough viscosity required for casting, the maximum volume fraction of AP (φ_AP) exists for the used AP. φ_AP is obtained as a function of ε_max. φ_AP increases with decreasing ε_max. 3) It is necessary to increase φ_AP for a high performance AP/HTPB propellant. The addition of surfactant and the coating on an AP particle are effective to increase φ_vc and φ_AP increases with increasing φ_vc. The increase in φ_vc is attributable to the improvement in the wettability between the AP and HTPB prepolymer by these operations.

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The adsorption of alcohol and the alkoxylation reaction on a silica surface were studied in solution systems. The over-all adsorption equilibria are expressed by the composite adsorption isotherms, which can show the influence of the kind of particles and solvents. The volume-filling model can be successfully applied to determine the individual isotherms. The surface alkoxylation reaction in benzene solutions was studied in comparison with that in aqueous solutions. The number of the formed alkoxyl groups was measured against the equilibrium concentration in a solution containing silica particles. In this paper, the expression of equilibrium constant is discussed, and the values are reported for various systems. The equilibrium constant for methanol is much larger than for other alcohols both in aqueous and benzene solutions.

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Fluidized bed granulators have been installed in pharmaceutical companies, and many trial studies to clarify the granulation mechanism have been reported over the past years. A granulation model was proposed in the previous study which was mainly concerned with the moisture content of powder in tapered-fluidized bed granulation. It was also pointed out that the viscosity of the binder liquid could be one of the important factors governing the granulation at a lower moisture content. In this study, the effects of the binder viscosity on particle agglomeration were evaluated for the purpose of explaining its contribution to particle agglomeration. Experimental results revealed that the initial agglomeration rate was determined by the binder viscosity. Based on these results, an agglomeration model was proposed taking account of the effects of the binder viscosity. Finally, it was shown that the value of the average granule size could be estimated by the moisture content and the binder concentration in the powder.

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Dynamic simulations of three-dimensional granular particles are performed using a distinct element method. Binary mixtures in a rotating drum are segregated into three bands. In this work, the segregation process can be understood in two stages: (1) an earliner stage diffusion processes that work to form segregated narrow bands, and (2) a later stage in which they are stabilized by cohesive forces operating at the boundaries of the bands.

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