Thermal stability of an explosive detonator

Abstract

Mercuric 5-nitrotetrazole is a possible replacement for lead azide. The thermal decomposition peak maximum ranged from 185 to 270°C as the heating rate increased from 0.1 to 100°C min −1. The activation energy and frequency factor for thermal decomposition were determined from dynamic and isothermal DSC and isothermal TG data; the average values were 38.8 kcal mol −1 and 3.56×10 14 s −1. A half-life experiment confirmed the kinetic constants and indicated that the decomposition reaction was first order. The heat of explosion was determined by a pressure DSC test and found to be 2587 J g −1. The linear coefficient of expansion was 37±2×10 −6°C −1 from −60 to 160°C and indicated secondary transitions near −10 and 90°C. The specific heat was 0.0003154 T+0.1339 in the region −40–90°C. The critical temperature for a slab with a half-thickness of 0.035 cm was calculated to be 232 °C.