ENHANCED REACTIVITY OF ALUMINUM POWDERS BY CAPPING WITH A MODIFIED GLYCIDYL AZIDE POLYMER

摘要

Aluminum powder is a significant component of many energetic formulations for rocket propel-lants and explosives due to its high combustion enthalpy on both a mass and volumetric basis. The combustion properties of these formulations can be enhanced further through the use of aluminum nanoparticles including shorter ignition delay, shorter burning time, and more complete combustion. High-energy ball milling was used as a method to produce aluminum-functionalized nanoparticles. This method is based on the reaction of the new metallic surface generated by grinding with an organic functionalized compound. In order to enhance the reactivity of aluminum powders coated by organic layers, we replaced the organic functionalized compound with an energetic polymer-glycidyl azide polymer (GAP). To achieve a desirable reactivity of GAP with aluminum particles, GAP plas-ticizer has been chemically modified by the partial reactions of azide groups on the polymer chain. The modified GAP (GAPm) was grafted onto the aluminum particles by the reactions of acid groups and aluminum in a simultaneous reaction milling. The aluminum particles coated with GAPm were characterized by the Brunauer-Emmett-Teller surface area analysis technique and scanning electron microscopy. Thermal gravimetric and differential thermal analyses were also used to carry out a study on the reactivity of the coated powders. Several different formulations of these coated powders combined with a binder were produced to investigate the influence of energetic capping of nanoparticles on the heat of combustion of these novel solid fuels.