Dynamic mechanical signatures of Viton A and plastic bonded explosives based on this polymer

The complex shear moduli of the fluorelastomer Viton A and four plastic bonded explosives LX‐04, LX‐07, LX‐10, and LX‐11, which use this polymer as a binder, have been investigated. LX‐10, LX‐07, LX‐04 and LX‐11 are composites of 94.5, 90, 85 and 80% 1, 3, 5, 7‐tetranitroazacyclooctane (HMX) explosive, respectively, and Viton A. Viton is a random copolymer of 7 vinylidene fluoride and 2 perfluoropropene monomers. In the temperature range from −150 to 120°C, two relaxations, the β relaxation at −80°C and the glass transition at −22°C, were observed as peaks in the loss modulus in Viton A at 0.1 Hz. A third relaxation, Tα, was found above Tg in all four explosive formulations. The plastic bonded explosives (PBX's) showed antiplasticization phenomena. Tg of the explosives increased 2–3°C as the concentration of binder was reduced in 5% steps. Samples from the same original lot of LX‐04 were evaluated after 20–23 years of service. The alpha relaxation occurred at 60°C as a peak in the loss modulus at 1 Hz. Both the beta and alpha relaxations were very broad and an accurate maximum for these relaxations was difficult to determine.