Graded polymer composites using twin-screw extrusion: A combinatorial approach to developing new energetic materials

The development of new energetic materials is a time-consuming, laborious, and sometimes dangerous process. Batch approaches are most commonly used, especially for energetic materials consisting of polymer composites. Recently, a manufacturing technology known as Twin-Screw Extrusion (TSE), has been demonstrated to increase the safety and affordability for manufacturing composite energetic materials. This technology is also ideally suited to manufacturing graded polymer composites through transient operating and/or feed conditions. In this paper, the TSE process is employed to fabricate graded polymer composites in a combinatorial approach for developing new energetic materials. Graded composite energetic materials with 79–87% solids loading of Ammonium Perchlorate are processed. The dependence of burning rate properties on the variation in composition was determined through strand burning tests. These results were compared with a conventional design of experiments approach using the Kowalski algorithm. The correlation of composition to properties over a range of compositions between the new combinatorial approach and the conventional design of experiments approach validates the use of TSE processing as a combinatorial approach to developing new energetic materials. Because the TSE process is used to manufacture both energetic and non-energetic composite materials, the combinatorial approach can also be applied to the development of new non-energetic polymer composites for applications such as control and sensing.