Optimization of HES 5808 Cody Parker- BAE Systems RFAAP Process and Product Development Engineer 05/15/2018 Christine Knott- NSWC IHEODTD Chemical Engineer 05/15/2018 Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

What is HES 5808? The HES 5808 High Temperature Resistant family of propellants are used in multiple CAD/PAD applications with data rights owned by BAE Systems (Radford AAP) and originally developed by Hercules Powder Company at the Kenvil, NJ plant. Transition of the production of HES 5808 propellant back to BAE (Radford AAP) is in progress via a Defense Ordnance Technology Consortium (DOTC) contract. Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

Understanding the Problem Internal Cracking/Fracturing Internal fracturing inside the grain between perforations can cause variation in performance Rough Surface Small pits visible on the exterior of the grain Both conditions create cartridge performance variation Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

Understanding the Problem Closed vessel testing of 5808.32 in a 700cc bomb and 0.2 g/cc loading density (140g charge weight). Max pressure observed was 33,000 psi which is significantly higher than pressures seen in cartridge applications. Shot to shot Variation seen in Dynamic Vivacity and Pressure vs. time (Pt) performance. Expect variation to be similar or greater at lower pressures or in applications where one or a few grains are used. Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

Understanding the Problem Geometry The HES 5808 family of propellant consists of many different geometries varying from a small flake (5808.17) to a large seven-perf grain (5808.32) depending on the cartridge application. The larger geometries tend to produce grains with a rough surface and internal cracking. Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

Current Initiatives Internal Cracks No Internal Cracks Areas of focus: Propellant Formulation Solids Fill % Plasticizer to Polymer Ratio Mixing Parameters Ingredient preparation Order of addition Solvent System Solvent Used Solvent Ratios Solvent Loading Blocking Propellant Consolidation Drying Ramp Temperature No Internal Cracks Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

HES 5808 Chemical Composition There are three ingredients in this highly solids loaded propellant that can be adjusted. Ammonium Perchlorate percentage and binder ratio (MPEG/CA) have been investigated. Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

Investigating the Solids/Binder ratio Several formulation ratios were examined: High solids fill, High plasticizer:polymer ratio: improved internal, poor external quality High solids fill, Lower plasticizer:polymer ratio: poor internal, improved external quality Lower solids fill, Lower plasticizer:polymer ratio: improved internal and external quality Each formulation change yielded mixed results in regards to ease of manufacture, external quality, and internal quality. Several mixes provided excellent external quality, but yielded poor internal quality due to cracking. Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

Investigating the Solids/Binder ratio Several formulation ratios were examined: High solids fill, High plasticizer:polymer ratio: improved internal, poor external quality As shown in the picture on the right, 3 of 30 grains had internal cracking. 25 of 30 grains photographed Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

Investigating the Solids/Binder ratio Several formulation ratios were examined: High solids fill, Lower plasticizer:polymer ratio: improved external, poor internal quality As shown in the picture on the right, 27 of 30 grains internal cracking. The circled grains are the grains that did NOT have internal cracking. 25 of 30 grains photographed Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

Investigating the Solids/Binder ratio Several formulation ratios were examined: Lower solids fill, Lower plasticizer:polymer ratio: improved internal and external quality As shown by the pictures on the right, this particular solids/binder ratio produced grains with a smooth surface and no internal cracking between the perforations. Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

Improving the Process Process conditions are critical when manufacturing 5808 propellant: Solids/Binder ratio Process solvent ratio Mix preparation and homogeneity Dough consolidation and solvent equilibrium Drying process Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

Improving the Process Mix Preparation and order of addition: Significant progress has been made to determine the best methodology to prepare ingredients for a mix of 5808. The former method required a “wicking” period of 16 hours where Ammonium Perchlorate, MPEG, and the process solvents were combined. The improved method is to completely solubilize the Cellulose Acetate using the chosen solvent system and plasticizer, MPEG. A “waiting” period is still required; however, we have found that this method increases the over all strength of the propellant strands as they are extruded. Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

Improving the Process Solvent System plays a big role in processing 5808: Historically, Acetone and Ethanol have been used to manufacture 5808 propellant; however, a less volatile solvent is needed to improve handling and processing the propellant. In recent years, several different process solvents have been explored. Ethyl Lactate, Butyl Acetate, and the combination of both, ELBA solvent, have been utilized to improve processing. Most recent mixes have used a combination of Ethanol, Acetone, and ELBA solvents at differing ratios and loadings. Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

Improving the Process Effective Mixing and Propellant/Solvent Equilibrium plays a crucial role: Homogeneity of the propellant dough has been a key item of focus for producing the 5808 propellant. This includes the total time of effective mixing; as well as, loading the material into a blocking press to ensure uniformity in the finishing press. BAE Radford does not have a blocking capability for the small scale operations but efforts are being made to have this capability in place for future mixes of 5808. Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

The next step Forward Additional mixes are scheduled for the end of May at NSWC IHEODTD facility to scale-up early mixes that showed promise. Additional mixes are scheduled for the end of June/early July at the BAE Radford facility. These mixes will investigate the following parameters to improved grain quality: Down select solids/binder ratio showing promise Implement improved ingredient preparation method Down select ratio of process solvents showing promise Implement blocking operation Implement drying process Distribution Statement A (18-073): Approved for public release, distribution is unlimited.

Thank you Distribution Statement A (18-073): Approved for public release, distribution is unlimited.