Dielectric studies of the effect of water on the relaxation properties of nitroglycerine-nitrocellulose mixtures

Abstract

Dielectric relaxation and water adsorption data are reported on mixtures of nitrocellulose and nitroglycerine which have been exposed to moisture to varying degrees. It was observed that the characteristics of these systems depend on the level of nitrogen in the base polymer. At 10.9% hydroxyl sites still exist which can effectively interact with the moisture, whereas at 12.9% the free hydroxyls appear to be incorporated into the ordered semi-crystalline regions of the polymer. The addition of water to nitroglycerine-nitrocellulose mixtures has little effect on the dominant beta relaxation other than to narrow the distribution of relaxations. The relaxation process is, in this case, associated with a cooperative relaxation of nitroglycerine moieties. Water has the effect of decreasing the cooperativity of the beta relaxation process.