Effect of polymer coating on ammonium nitrate substrate

Abstract

SynopsisPrilled, spheroidized, and granular ammonium nitrates (AN) were coated with poly-(chloro-p-xylylene) (parylene C) by a vapor deposition polymerization technique. Particles of AN with a 0.2% coating remain free flowing after long exposure to ambient conditions. The effectiveness of the coating as a moisture barrier on the three forms of AN was found to be in the order spheroids > prills > granules. Water adsorption isotherms and hygroscopicity determinations indicate that a 0.7% coating hydrophobes the surface of AN by approximately one order of magnitude. The parylene C/AN interface exhibits chemical and physical stability at elevated temperatures.

Stabilization of ammonium azide particles through its microencapsulation with some organic coating agents

“…In alignment with previous reports [13][14][15][16][17][18][19][20], some coating agents such as paraffin, wax, nitrocellulose, oleic acid, stearic acid, Viton, melamine, polystyrene and cellulose acetate may be used as a coating agent in our microencapsulation procedure. However, among them, nitrocellulose, stearic acid and Viton have been chosen due to their relatively high combustion and gas generation abilities and good solubility in conventional solvents which are desired for related applications [20][21][22].…”

“…Effect of the coating procedure on the microencapsulation Several procedures were previously employed for microencapsulation process including vapor deposition polymerization, rapid expansion of supercritical fluid, magnetically assisted impact coating (MAIC), suspension aerosol gas phase, solvent/non-solvent and solvent evaporation techniques [13][14][15][16][17][18][19][20].While some of these methods need sophisticated apparatus, two latter ones can be exploited using conventional laboratory equipments. Our primary evolutions of solvent/non-solvent and solvent evaporation methods have shown that a significant loss of sample occurs in the latter one.…”

“…Beside thermochemical and spectral methods, morphological investigation of microencapsulated solid, through SEM and TEM analysis, releases proper information about coating quality and effectiveness of applied procedure [13][14][15][16][17][18][19]. Fig.…”

“…This technique can be used to limit the reaction of two active species due to physical separation. In recent decades, microencapsulation techniques were widely used in diverse fields of sciences and technologies such as polymerizations, drug delivery, particulate design, micro and nanoparticles production [8][9][10][11][12], however, few attempts have been made for the modification of the surface morphology and thermal stability of inorganic reactive powders, for instance, coating of the NH 4 NO 3 particles by vapor deposition polymerization technique [13], coating of the NH 4 ClO 4 by solvent/non-solvent method [14], Powder Technology 208 (2011) 137-143 improvement of humidity resistance of Mg powder by using magnetically assisted impact coating (MAIC) [15] and rapid expansion of supercritical fluid [16], passivation of the surface of Al nano powders [17,18], formation of organic coating on Ag nano powders using an aerosol technique [19] and our recent study on the coating of NaN 3 particles with nitrocellulose by solvent/non-solvent method [20].Also, the use of particle coating techniques in pyrotechnics and explosives is a field of study which appears to be gaining importance [21][22][23][24].…”

MD-DFT Calculations on Dissociative Absorption Configurations of FOX-7 on (001)- and (101)-Oriented Crystalline Parylene Protective Membranes

“…Recently, it was suggested that polymers can be coated on the surfaces of energetic materials (such as explosives, propellants, and pyrotechnics) to act as protective membranes [15]. Surface crystalline polymers are well known to decrease explosive sensitivity and infiltration [16]. Moreover, the explosive cannot crystallize on the surface of the protective membrane.…”