| Nanofibers were added to simulant energetic materials via twin screw extrusion (TSE) in an effort to characterize the degree of dispersion of the fibers into a highly filled polymer composition used in the production of solid gun propellants. This work was an attempt to optimize process conditions, such as, screw speed and feed rate that will result in maximum dispersion with minimal breakage of the fibers. Simulant material properties including density, Shore A hardness, and resilience were determined. Values of specific heat capacity, obtained by differential scanning calorimetry (DSC), were used to predict a theoretical melt temperature during TSE via an energy balance equation. The thermal diffusivities of the model polymer and filler were determined by the dynamic cooling of a cylindrical sample. An energy balance was performed and predicted values for the melt temperature (124°C) and the energy supplied to the melt during twin screw extrusion (3641 J/min). The specific energy was calculated for all twin screw extrusion trials. (Abstract shortened by UMI.)... |
