(604e) Twin Screw Extrusion Of Nanoenergetics With Processing Geometries That Are Tunable To The Targeted Thermo-Mechanical History

The dispersion of nanoparticles into energetic formulations requires relatively high shearing stresses to be applied to allow the deagglomeration of particle clusters and the encapsulation of the separated nanoparticles by the binder phase. For such dispersion the twin screw extrusion process provides multiple advantages over the conventional batch processing methods including a significantly higher surface to volume ratio for better process and product quality control and flexible and tunable geometries (combinations of reversing or forwarding fully-flighted or kneading disc type screw elements configured at differing pitches and stagger angles) to tailor the thermo-mechanical history that the energetic formulation is to be exposed to during the incorporation of the nanoparticles. Here the technology base will be introduced and results from processing studies obtained with a MPR mini twin screw extruder, in conjunction with 3-D FEM based mathematical models of the process and the detailed rheological characterization of formulations involving gel based binder systems and different types of nanoalumina, will be presented.