Thermochemistry of Normal and Basic Lead Styphnates Using Differential Scanning Calorimetry
Abstract
The DSC thermogram under non-isothermal conditions from the thermal decomposition of normal lead styphnate, RD 1303M, a component of several primer mixes, is characterised by two peaks. The first is a low temperature endotherm which occurs around 415 K (at a heating rate of 5 k/min) and corresponds to the loss of water from the crystal lattice, the heat of reaction associated with this process is 67 + or - 8 J/g1. The second peak is strongly exothermic with a heat of reaction of 1960 + or - 70 J/g and is associated with an ignition process having an apparent activation energy of 184 + or - kJ/mole and Arrhenius pre-exponential log sub 10 A/(s) of 14.9 + or - 0.5. It is estimated that the T of I of RD 1303M at a heating rate of 5 K/min occurs between 518 K (the temperature where slow decomposition commences) and 542 K (the onset temperature for rapid decomposition), using the DSC method. The thermal decomposition of basic lead styphnate, RD 1346, is characterised by a single large exothermic peak, corresponding to a process with an apparent activation energy of 203 + or - 12 KJ/mole and Arrhenius pre-exponential, log sub 10 A/(s) of 17.7 + or - 0.5. The heat of reaction for the complete process is 1170 log sub 10 45 J/g, and at a heating rate of 5 K/min, the T of I occurs between 505 K and 525 K (DSC method). Line shape analysis of the DSC traces from normal lead styphnate suggests its decomposition follows a first-order reaction.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1986
- Accession Number
- ADA174717
Entities
People
- Daniel J. Whelan
- Michael Maksacheff
Organizations
- Defence Science and Technology Group