Modeling and Practical Approach for Reduction of Nitroglycerin (NG) Migration in Double Base Solid Propellants

Double base propellant consists of two main components, nitrocellulose and nitroglycerin and nitroglycerin fickian diffusion from inter to surface of propellant, is the main problem of this type of propellants. Thus, providing a model for predicting migration during storage and also practical solutions in decreasing of nitroglycerine migration is one of the favorite subjects for propellant specialists. One of the ways to decrease migration, is using of modified inhibitor based on mineral unsaturated polyesters contain mineral fillers. Herein, at the first, several unsaturated polyester inhibitor in the presence of mineral filler (nano clay, modified nanoclay, silica, alumina trihydrates,15%, and alumina trihydrates, 30%) were synthesized and the influence of nitroglycerin was modeled by immersion test and the diffusion coefficients were calculated. The results showed that the modified unsaturated polyester inhibitor has a diffusion coefficient of 1.027×10-4 cm2/s that in the presence of alumina three hydrates as the mineral filler, the penetration coefficient decreased to 6.777×10-6 cm2/s. Also the relative migrated mass at the infinitive time to the mentioned inhibitor was 6.4622 and it is decreased to 2.469 in the presence of mineral filler. So, presence of filler in the inhibitor matrix, can significantly decreases nitroglycerin diffusion, increasing the safety and the lifetime of propellant .