REACTION-MECHANISMS IN SHOCKED, INTERCALATED GRAPHITE AND BORON-NITRIDE

The traditional ways of developing increasingly energetic materials us ually lead to an increase in shock and impact sensitivities. It is, th erefore, of practical and theoretical importance to design model, high ly-energetic polycrystalline systems which will clearly indicate, at t he molecular level, the interplay between the shock-induced reaction m echanisms and the associated excited lattice states. Theoretical and e xperimental studies indicate that such systems may possibly be constru cted from special materials such as high-quality pyrolytic, layered gr aphite and hexagonal boron nitride (BN) crystals. Although each layer of graphite and BN is one of the most stable structures in nature, int ercalation of the crystals with various oxidizing agents can yield ene rgetic systems with the desired properties. As an example, intercalati on with HNO3 gives crystals of density 2.20 g/cc. The optimal position ing of the HNO3 molecules between the BN layers allows the rapid forma tion of B2O3 in a single step with a large release of energy. A possib le triggering mechanism is the shock-induced, partial sps hybridizatio n of the layers as a result of kink band formation.