Effect of prior treatment on the chemical reactivity of inorganic perchlorates Ph.D. Thesis

Abstract

The effect of mechanical and thermal pre-treatment on the chemical reactivity of inorganic perchlorates has been studied. The perchlorate system was chosen in view of its importance as a source of oxygen in solid rocket propellants. The materials studied were (1) ammonium perchlorate, (2) sodium perchlorate, (3) potassium perchlorate, (4) rubidium perchlorate and (5) caesium perchlorate. A lot of work has been done on the thermal decomposition of these materials but relatively less attention has been paid to the effect of pre-treatment on their reactivity. It would be advantageous if it were possible to modify by some means the decomposition characteristics of these high energy materials. The present programme consists of an investigation of the phenomenological and mechanistic aspects of pre-compression and pre-heating. The techniques employed in the investigation were DTA, TGA, infrared spectroscopy and X-ray diffraction. It has been found that both pre-compression and pre-heating have a marked influence on the rate of decomposition of these materials. A clue to the causal factors in the pre-treatment is provided by the IR spectra and X-ray diffraction patterns of the pre-compressed and pre-heated samples. The important fact emerging from the investigation is that pre-compression and pre-heating provide a convenient means of modifying the chemical reactivity of metastable materials in general. A comparative study of the phase transformations in the alkali metal perchlorates has also been carried out. The effect of prior mechanical and thermal treatment on the transformation temperatures and on the thermal hysteresis has been investigated.