As a continuation of our effort to understand degradation mechanisms of a eutectic mixture of bis(2,2-dinitropropyl)acetal (BDNPA) and bis(2,2dinitropropyl)formal (BDNPF) (referred to as NP) under various environmental conditions, we investigated the thermal stability of NP under water and 74% relative humidity (RH) environments at temperatures below 70 °C. Based on a comprehensive characterization of samples aged over a period of two years, we conclude that in the presence of water the reaction pathways of the NP degradation are different from those observed in air or under nitrogen atmosphere. We found that the physical state of water molecules plays an important role as it determines the ability of oxygen to participate in the NP aging process. Based on the results obtained in Parts A and B of these studies, we conclude that the rate of NP degradation increases in the order: nitrogen < water < air < water vapor + air.

We investigated the chemical and thermal stability of a eutectic mixture of bis(2,2-dinitropropyl)acetal (BDNPA) and bis(2,2-dinitropropyl)formal (BDNPF) (referred to as NP) in various environments at temperatures below 70 °C. Changes in the chemical composition of aged samples were characterized using TGA, FTIR, GPC, ESI-MS, and 1 H NMR spectroscopies over a period of two years. The results show that the initial signs of NP degradation can be detected as early as 12 months at 70 °C in air. The initial step in the degradation is the elimination of HONO molecules, followed by the formation of nitroso-alcohol isomers. While the temperature plays a key role in determining the degradation kinetics of the initial stages, the absence or presence of oxygen determines the types and rates of formations of various isomers and intermediates during the thermal decomposition processes. In addition, oxygen accelerates the decomposition of the isomers and intermediates, whereas nitrogen has a stabilizing effect. BDNPA shows higher reactivity than BDNPF regardless of the aging conditions, which is attributed to the presence of an extra methyl group in its structure.

Oysters have an impressive ability to overcome difficulties of life within the stressful intertidal zone. These shellfish produce an adhesive for attaching to each other and building protective reef communities. With their reefs often exceeding kilometers in length, oysters play a major role in balancing the health of coastal marine ecosystems. Few details are available to describe oyster adhesive composition or structure. Here several characterization methods were applied to describe the nature of this material. Microscopy studies indicated that the glue is comprised of organic fiber-like and sheet-like structures surrounded by an inorganic matrix. Phospholipids, cross-linking chemistry, and conjugated organics were found to differentiate this adhesive from the shell. Symbiosis in material synthesis could also be present, with oysters incorporating bacterial polysaccharides into their adhesive. Oyster glue shows that an organic-inorganic composite material can provide adhesion, a property especially important when constructing a marine ecosystem.

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One of the great challenges of inertial confinement fusion and high energy density experiments is understanding the effects of mix on thermonuclear burn. The MARBLE campaign, conceived at Los Alamos National Laboratory, aims to gather new insights into this issue by utilizing unique target capsules containing polymer foams of variable pore sizes, tunable over an order of magnitude. Such capsules allow the degree of initial heterogeneity to be controlled experimentally for the first time. Here, we describe the various characterization efforts used to gain understanding of the chemical structure and behavior of the foam. Previous experiments were not sensitive to foam physical properties, and the MARBLE platform has aided in the development of techniques to measure foam properties such as deuterium content, density variation, hydrogen adsorption, and pore size and volume distribution.