Mechanical properties of plastic-bonded explosive binder materials as a function of strain-rate and temperature

Compression measurements were conducted on three explosive formulation binders, extruded Estane, plasticized Estane, and plasticized hydroxyl-terminated polybutadiene, as a function of temperature and strain rate. The mechanical response of the Estane was found to exhibit the strongest dependency on strain rate and temperature and higher flow strength for similar test conditions of the three materials tested. Plasticized Estane was less sensitively dependent on strain rate and temperature, followed by the plasticized HTPB. The viscoelastic recovery of all three binders is seen to dominate the mechanical behavior at temperatures above the glass transition temperature (T-g). There is a pronounced shift in the apparent T-g to higher temperatures as the strain rate is increased. Two distinct behaviors are observed in the binders below the T-g. At low strain rates, the binders exhibit a yield behavior, followed by a drop in the flow stress, which may or may not recover. At high strain rates, the load drop does not occur and the flow stresses either gradually increase, as in plasticized HTPB, or it levels out as seen in the Estane-based binders.