EXPERIMENTAL-STUDY ON ESTIMATION OF UPPER LIMIT OF AMMONIUM-PERCHLORATE CONTENT IN AMMONIUM-PERCHLORATE HYDROXYL-TERMINATED POLYBUTADIENE COMPOSITE PROPELLANT

Because of the requirements for the preparation of ammonium perchlorat e (AP)/hydroxyl-terminated polybutadiene (HTPB) composite propellant, there is an upper limit, phi(AP) (wt%), of AP content in propellant. I n the present study, attempts were made to estimate phi(AP). The visco sity, eta(phi) (Pa.s), in casting of uncured propellant prepared at ph i(AP) is approximately constant. When the apparent viscosity in castin g of the uncured propellant is almost the same as eta(phi), the AP con tent of the uncured propellant is almost equal to phi(AP). phi(AP) inc reases with a decreasing void fraction, epsilon(max)(-), at the loose packing of AP powder. In the range of measurement (0.568 less than or equal to epsilon(max)less than or equal to 0.882), the relationship be tween phi(AP) and epsilon(max) can be represented by the following equ ation. phi(AP) = -89 epsilon(max)(2) + 86 epsilon(max) + 65. According to the above equation, phi(AP) can be estimated from epsilon(max).