Influence of differently cured polymeric binders on rheology properties of plastic explosives

Abstract

Plastic Explosive Compositions consisting of HMX and liquid polyurethane binder were prepared in order to determine influence of differently cured polymeric binders on rheological properties of plastic explosives. First, a set of polymeric binders was prepared in polyaddition reaction between HTPB and IPDI, with varying NCO:OH ratio and examined through the standard and non-standard rheological tests on a dynamic rotational rheometer. Viscosity curves of polymeric binders show viscosity increase with NCO:OH ratio increase, as expected. Amplitude sweep tests reveal liquid-like structure of PEs, with structure strength increase with higher NCO:OH ratio of polymeric binder used, and limiting values of LVER vary from 10-3 to 10-2 strain. Results of creep test reveal that with increase of NCO:OH ratio of polymeric binder in PE zero-shear viscosity increase and viscous portion deformation decrease. Also, penetration decrease with increase of NCO:OH ratio. The obtained results indicate that initial rheology testing is crucial in plastic explosive formulation regarding their processability and physical properties.