Dynamic Mechanical Analysis of Plastic Bonded Explosives

摘要

Most useful explosives are crystalline solids coated with a binder, which holds therncrystals together. The addition of the polymer to the explosive allows the material to be pressedrnto high density and have good mechanical properties. Dynamic mechanical analysis (DMA) wasrnused to find the glass transition temperature of the PBX and compare with the neat polymer. Thernsamples are heated in steps from below beta transition in its glassy region to its softeningrntemperature. Several frequencies are used at each step to determine the effect of frequency on therntransition temperatures. The effects of aging of the binder on the mechanical properties arernchanges in the storage modulus over time. For example, an increase in crystallinity orrncrosslinking can increase the stiffness of the PBX. One PBX studied is PBX 9502, 95-wt%rntriaminotrinitrobenzene (TATB) with 5 wt% Kel-F 800 copolymer of chlorodifluoroethylene andrnvinylidene fluoride.