Technology Description

This project explored the use of novel processing techniques to reduce the amount of waste and emissions generated in the conventional manufacturing of 2.75-inch rocket motor grains. The new process used a shear roll mill to manufacture solventless double-base propellant pellets to provide a feedstock to a twin screw mixer/extruder. The new manufacturing process was to be evaluated relative to the conventional batch process for acceptable product performance, minimum environmental impact, and low manufacturing cost. The merits of the new continuous process were to be assessed by characterizing and comparing the product manufactured and the amount of waste and toxic air pollutants potentially generated by the twin screw process to the conventional batch process, in addition to trying to validate the cost reduction of the new technology. Standard propellant characterization tests were to be used to compare the twin screw and conventional batch products if possible. Similarly, the propellant grains manufactured by each process were to be tested to determine ballistic performance. A detailed mass balance on both processes was to document the waste and air emission reduction. A shear roll mill process model was developed by the U.S. Army Armament Research, Development, and Engineering Center to conduct an independent environmental and cost audit.