Following conclusions were drawn from this study:
(i) Moisture contents of propellant solid ingredients do affect
the mechanical properties of the composite propellants.
(ii) Ammonium oxalate is a highly hygroscopic compound
and easily absorbs water from the air. A relatively longer
time is required to completely remove the moisture from
AO.
(iii) Moisture contents of AO have a great effect on propellant
mechanical properties. Tensile strength and modulus
increase and max. elongation, in general, decreases by decreasing
the AO moisture contents.
(iv) A too long drying time of solid materials has an adverse
effect on propellant mechanical properties.
The actual effects of moisture contents and the drying conditions
of solid ingredients on the mechanical properties of the
propellant are very complex and further work is required to
study the mechanism in detail.