Abstract: The formation mechanism of pore structure of ball propellant with micro-pores made by double emulsion method is revealed. The formation and changing rule of pore structure are studied through sampling, microscopic observation and image analysis during emulsifying, balling and solvent distilling. The results show that the major parameters influencing the shape forming of pore structure are the conditions of emulsion and solvent distillation. The shape and size distribution of dispersed droplets in nitrocellulose emulsion are in basic agreement with the pore structure and pore size distribution in finished ball propellant. As a result, the pore morphology of ball propellant is determined by the emulsification conditions. The conditions of shape forming process have no significant effect on the size and morphology of the pores, while the solvent evaporation conditions have greater influence on the pore size distribution. The faster the solvent is distilled, the worse the pore structure uniformity is due to the agglomeration of pores. The pore structure uniformity of finished particles is improved effectively by reducing the speed of solvent distillation. The pore structure of nitrocellulose ball propellant with micro-pores made by double emulsion method is substantially determined by the morphology of the disperse phase droplets in nitrocellulose emulsion.

Key words: ordnance science and technology, energetic material, double emulsion method, micro-pore, ball propellant, pore structure, formation mechanism