The impact of metastable intermolrecular nanocomposite particles on kinetic decomposition of heterocyclic nitramines using advanced solid-phase decomposition models

Oxygen atoms on the surface of oxide catalysts have low coordination number; they are negatively charged. Surface oxygen can act active sites for decomposition of energetic nitramines (i.e. HMX); additionally hydrous surface can release active ȮH radicals. Colloidal oxide particles can fulfil these requirements. Furthermore oxide particles can induce thermite reaction with aluminium particles. This study reports on the facile fabrication of colloidal ferric oxide particles of 5 nm; Colloidal Fe2O3/Al binary mixture was integrated into HMX matrix via co-precipitation technique; uniform dispersion of nanothermite particles was verified using SEM. Naonothermite particles experienced dramatic change in HMX thermal behaviour with an increase in total heat release by 63 %. The impact of themrite particles on HMX kinetic decomposition was evaluated using an integral isoconversional method of KAS, and Kissinger models. The mean value of apparent activation was reduced by 23.5 % and 24.3 % using Kissinger and KAS models respectively. This dramatic change in HMX decomposition can be ascribed to the ferric oxide reactivity and the facile integration of colloidal thermite particles.

A Case Study of Polyetheretherketone (II): Playing with Oxygen Concentration and Modeling Thermal Decomposition of a High-Performance Material

Kinetic decomposition models for the thermal decomposition of a high-performance polymeric material (polyetheretherketone, PEEK) were determined from specific techniques. Experimental data from thermogravimetric analysis (TGA) and previously elucidated decomposition mechanisms were combined with a numerical simulating tool to establish a comprehensive kinetic model for the decomposition of PEEK under three atmospheres: nitrogen, 2% oxygen, and synthetic air. Multistepped kinetic models with subsequent and competitive reactions were established by taking into consideration the different types of reactions that may occur during the thermal decomposition of the material (chain scission, thermo-oxidation, char formation). The decomposition products and decomposition mechanism of PEEK which were established in our previous report allowed for the elucidation of the kinetic decomposition models. A three-stepped kinetic thermal decomposition pathway was a good fit to model the thermal decomposition of PEEK under nitrogen. The kinetic model involved an autocatalytic type of reaction followed by competitive and successive nth order reactions. Such types of models were set up for the evaluation of the kinetics of the thermal decomposition of PEEK under 2% oxygen and in air, leading to models with satisfactory fidelity.

On the kinetic decomposition voltage of ternary oxides

The theoretical and experimental kinetic decomposition voltage in a ternary oxide under electric driving force.