Heat flow calorimetry of propellants - Effects of sample preparation and measuring conditions

Isothermal microcalorimetry measurements were performed on the double base ball propellant K 6210. The influence of different sample preparation techn iques and measuring conditions is discussed. The most important parameter i s the atmosphere above the propellant. If air is replaced by nitrogen a red uction of primary effects can be observed. A replacement by oxygen leads to a complete different decomposition reaction. Comparable effects are achiev ed when the ampoules are only filled to 25%. In this case oxidation reactio ns can be observed. Also using ampoules that are not tightly closed changes the decomposition reaction. All experiments were accompanied by stabiliser analyses (HPLC) that demonstrate the different decomposition reactions as well. Changing the temperature but leaving the sample preparation and measu rement conditions unchanged heat flow curves are observed that are similar in shape. That means that the decomposition reactions are comparably activa ted. Reducing the volume to lower the sample amount is not possible by addi ng glass balls because absorption/desorption reactions cover the first part of the decomposition reaction. If a glass rod is taken there is no change in the shape of the curve.