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Preparation and Characterization of Energetic Nanocomposites of Organic Gel – Inorganic Oxidizers
Author(s) -
Cudziło Stanisław,
Kiciński Wojciech
Publication year - 2009
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.200700267
Subject(s) - nanocomposite , materials science , chemical engineering , aqueous solution , salt (chemistry) , adsorption , resorcinol , sol gel , solvent , specific surface area , chemistry , catalysis , composite material , organic chemistry , nanotechnology , engineering
Two types of polymeric sols, resorcinol‐formaldehyde (RF) and resorcinol‐furfural (RFur), were mixed in a water‐containing medium with aqueous solutions of inorganic salts: NH 4 ClO 4 , Mg(ClO 4 ) 2 , and NH 4 NO 3 . After gelation and an ambient pressure drying, hybrid nanocomposites with properties of energetic materials were obtained. It was stated that salt concentration and addition of a second solvent (e.g., methanol or N , N ‐dimethylformamide) to the mixture of reagents have crucial meaning for gel formation. In the case when only water was used, the mixture of organic sol/inorganic salt did not transfer from sol to gel, and precipitates were formed. Conventional drying of wet gelled composites leads to rigid material called xerogels. The RF xerogels are red and RFur xerogels are black. Typically, xerogels are transparent at low salt concentration (below 30%). The microstructure, morphology, and some other properties of chosen composites were studied by means of HR SEM, AFM, XRD, DTA/TG, and N 2 adsorption isotherm techniques. SEM observation revealed that sizes of the oxidizer particles vary from less than 100 nm to ca. 1000 nm. XRD analyses also confirmed the presence of nanometer‐sized crystals of oxidizers in some formulations. The specific surface area of polymeric matrix/oxidizer composites was found to be in the range from 0.002 to 0.3 m 2 g −1 . After removing the salt from the composites (by extraction with boiling water), the specific surface area grows even up to 210 m 2 g −1 . TG/DTA analyses showed that the tested composites decompose as typical energetic materials. If pre‐heated and exposed to flame, some of them (especially RF/Mg(ClO 4 ) 2 composites) undergo violent deflagration with loud sound and flash effect.