Conceptualize, Synthesize, Formulate, Test, Demonstrate Unclassified. Distribution A: Approved for Public Release. Distribution is unlimited. Explosive Light-Cured Binders Optimized with JMP Edward D. Cooke*, Melissa N. Jablonski, Eric R. Beckel, Alexander J. Paraskos Background Secondary explosives are loaded into munition casings via three methods: melt poured, pressed, and cast cured. Cast cured explosives are composites of solid nitramines and polymeric binders. The binders consist of multiple ingredients that chemically cure to produce a rubbery composite material. Novel engineering applications have developed a need for a cast cure binder that cures when exposed to light. In an attempt to employ “Click Chemistry”, a novel, energetic pre-polymer was designed with an alkyne terminus capable of curing with a thiol cross linker in the presence of a photoinitiator and light source. Prior to incorporation into an explosive, this binder system required robust evaluation in order to fully understand the reaction chemistry and resulting material properties. Due to limited pre-polymer availability, a designed experiment was selected to direct such an evaluation. Design and Execution The continuous factors affecting the cure chemistry and cured product properties included the thiol to alkyne ratio, photoinitiator concentration, and light intensity. An additional categorical factor of “thiol type” was also examined. A sequential DOE approach was used to screen these factors in a total of 22 runs. A half fractional factorial design with centers was initially run to identify the main effects and interactions that were active in the model and to test for model curvature. This was followed up with an I-optimal augmentation focused on breaking alias chains and modeling the curvature to determine the optimal binder ingredients and curing conditions for the binder system. 10 gram samples of binder were mixed according to the DOE parameter settings. Real Time Fourier-Transform Infrared spectroscopy (RT-FTIR) during light exposure was performed in triplicate to gather information about the cure kinetics and chemical conversions. Dog bone molds were filled, cured, and analyzed with a tensile tester to evaluate the mechanical properties. Additional responses gathered for each DOE run that are not presented include glass transition temperature, viscosity, and explosive energy. Thiol Conversion ETTMP-1300 Chemistry Results FTIR analysis discovered that the thiol peak is convoluted with another molecular moiety present in the binder system resulting in two overlaid Gaussian peaks that must be separated. Additionally, the alkyne and alkene peaks are convoluted with one another, so significant post-processing of the data is required. With respect to the thiol conversion, significant interactions were identified between the type of thiol and the thiol:alkyne ratio. However, FTIR results from the fractional factorial DOE indicated that ETTMP-1300 was beginning to react prior to light exposure and was thus removed from the follow up design. Initial alkyne conversion results indicate that several factors are affecting the model, thus requiring further input data for resolution. Mechanical Results Modulus, peak stress, and strain at peak stress values were all collected from the tensile tests. Modeling the modulus data from the screening DOE identified curvature, however without additional data, the specific active quadratics cannot be identified. Similar evidence of curvature and aliasing of model terms is also seen when modeling the peak stress and strain. Conclusions A sequential DOE successfully reduced the number of experiments and material required to initially screen several factors associated with a new cast cure binder system. Preliminary results indicate that optimization is achievable within the experimental parameters established for the DOE. Extensive data manipulation brought about by the specific cure chemistry is required before final models and trade-off analysis can be conducted. Explosives Research: Conceptualize, Synthesize, Formulate, Test, Demonstrate Acknowledgements The authors would like to acknowledge Colorado Photopolymer Solutions for their laboratory assistance and use of their facilities and instrumentation. This research was funded by the Energetic Materials and Advanced Processing (EMAP) program under the direction of Katherine Guarini. Conceptualize FTIR Thiol Peak Intensity *Edward D. Cooke Chemist, US Army ARDEC, Explosives Research Branch 973-724-4476. Edward.d.cooke2.civ@mail.mil Unclassified. Distribution A: Approved for Public Release. Distribution is unlimited. 1

Conceptualize, Synthesize, Formulate, Test, Demonstrate Unclassified. Distribution A: Approved for Public Release. Distribution is unlimited. Explosive Light-Cured Binders Optimized with JMP Edward D. Cooke*, Melissa N. Jablonski, Eric R. Beckel, Alexander J. Paraskos Background Secondary explosives are loaded into munition casings via three methods: melt poured, pressed, and cast cured. Cast cured explosives are composites of solid nitramines and polymeric binders. The binders consist of multiple ingredients that chemically cure to produce a rubbery composite material. Novel engineering applications have developed a need for a cast cure binder that cures when exposed to light. In an attempt to employ “Click Chemistry”, a novel, energetic pre-polymer was designed with an alkyne terminus capable of curing with a thiol cross linker in the presence of a photoinitiator and light source. Prior to incorporation into an explosive, this binder system required robust evaluation in order to fully understand the reaction chemistry and resulting material properties. Due to limited pre-polymer availability, a designed experiment was selected to direct such an evaluation. Design and Execution The continuous factors affecting the cure chemistry and cured product properties included the thiol to alkyne ratio, photoinitiator concentration, and light intensity. An additional categorical factor of “thiol type” was also examined. A sequential DOE approach was used to screen these factors in a total of 22 runs. A half fractional factorial design with centers was initially run to identify the main effects and interactions that were active in the model and to test for model curvature. This was followed up with an I-optimal augmentation focused on breaking alias chains and modeling the curvature to determine the optimal binder ingredients and curing conditions for the binder system. 10 gram samples of binder were mixed according to the DOE parameter settings. Real Time Fourier-Transform Infrared spectroscopy (RT-FTIR) during light exposure was performed in triplicate to gather information about the cure kinetics and chemical conversions. Dog bone molds were filled, cured, and analyzed with a tensile tester to evaluate the mechanical properties. Additional responses gathered for each DOE run that are not presented include glass transition temperature, viscosity, and explosive energy. Thiol Conversion Tri-thiol Chemistry Results FTIR analysis discovered that the thiol peak is convoluted with another molecular moiety present in the binder system resulting in two overlaid Gaussian peaks that must be separated. Additionally, the alkyne and alkene peaks are convoluted with one another, so significant post-processing of the data is required. With respect to the thiol conversion, significant interactions were identified between the type of thiol and the thiol:alkyne ratio. However, FTIR results from the fractional factorial DOE indicated that ETTMP-1300 was beginning to react prior to light exposure and was thus removed from the follow up design. Initial alkyne conversion results indicate that several factors are affecting the model, thus requiring further input data for resolution. Mechanical Results Modulus, peak stress, and strain at peak stress values were all collected from the tensile tests. Modeling the modulus data from the screening DOE identified curvature, however without additional data, the specific active quadratics cannot be identified. Similar evidence of curvature and aliasing of model terms is also seen when modeling the peak stress and strain. Conclusions A sequential DOE successfully reduced the number of experiments and material required to initially screen several factors associated with a new cast cure binder system. Preliminary results indicate that optimization is achievable within the experimental parameters established for the DOE. Extensive data manipulation brought about by the specific cure chemistry is required before final models and trade-off analysis can be conducted. Explosives Research: Conceptualize, Synthesize, Formulate, Test, Demonstrate Acknowledgements The authors would like to acknowledge Colorado Photopolymer Solutions for their laboratory assistance and use of their facilities and instrumentation. This research was funded by the Energetic Materials and Advanced Processing (EMAP) program under the direction of Katherine Guarini. Synthesize FTIR Alkyne Peak Intensity *Edward D. Cooke Chemist, US Army ARDEC, Explosives Research Branch 973-724-4476. Edward.d.cooke2.civ@mail.mil Unclassified. Distribution A: Approved for Public Release. Distribution is unlimited. 2

Conceptualize, Synthesize, Formulate, Test, Demonstrate Unclassified. Distribution A: Approved for Public Release. Distribution is unlimited. Explosive Light-Cured Binders Optimized with JMP Edward D. Cooke*, Melissa N. Jablonski, Eric R. Beckel, Alexander J. Paraskos Background Secondary explosives are loaded into munition casings via three methods: melt poured, pressed, and cast cured. Cast cured explosives are composites of solid nitramines and polymeric binders. The binders consist of multiple ingredients that chemically cure to produce a rubbery composite material. Novel engineering applications have developed a need for a cast cure binder that cures when exposed to light. In an attempt to employ “Click Chemistry”, a novel, energetic pre-polymer was designed with an alkyne terminus capable of curing with a thiol cross linker in the presence of a photoinitiator and light source. Prior to incorporation into an explosive, this binder system required robust evaluation in order to fully understand the reaction chemistry and resulting material properties. Due to limited pre-polymer availability, a designed experiment was selected to direct such an evaluation. Design and Execution The continuous factors affecting the cure chemistry and cured product properties included the thiol to alkyne ratio, photoinitiator concentration, and light intensity. An additional categorical factor of “thiol type” was also examined. A sequential DOE approach was used to screen these factors in a total of 22 runs. A half fractional factorial design with centers was initially run to identify the main effects and interactions that were active in the model and to test for model curvature. This was followed up with an I-optimal augmentation focused on breaking alias chains and modeling the curvature to determine the optimal binder ingredients and curing conditions for the binder system. 10 gram samples of binder were mixed according to the DOE parameter settings. Real Time Fourier-Transform Infrared spectroscopy (RT-FTIR) during light exposure was performed in triplicate to gather information about the cure kinetics and chemical conversions. Dog bone molds were filled, cured, and analyzed with a tensile tester to evaluate the mechanical properties. Additional responses gathered for each DOE run that are not presented include glass transition temperature, viscosity, and explosive energy. Alkyne Conversion (not normalized) Chemistry Results FTIR analysis discovered that the thiol peak is convoluted with another molecular moiety present in the binder system resulting in two overlaid Gaussian peaks that must be separated. Additionally, the alkyne and alkene peaks are convoluted with one another, so significant post-processing of the data is required. With respect to the thiol conversion, significant interactions were identified between the type of thiol and the thiol:alkyne ratio. However, FTIR results from the fractional factorial DOE indicated that ETTMP-1300 was beginning to react prior to light exposure and was thus removed from the follow up design. Initial alkyne conversion results indicate that several factors are affecting the model, thus requiring further input data for resolution. Mechanical Results Modulus, peak stress, and strain at peak stress values were all collected from the tensile tests. Modeling the modulus data from the screening DOE identified curvature, however without additional data, the specific active quadratics cannot be identified. Similar evidence of curvature and aliasing of model terms is also seen when modeling the peak stress and strain. Conclusions A sequential DOE successfully reduced the number of experiments and material required to initially screen several factors associated with a new cast cure binder system. Preliminary results indicate that optimization is achievable within the experimental parameters established for the DOE. Extensive data manipulation brought about by the specific cure chemistry is required before final models and trade-off analysis can be conducted. Explosives Research: Conceptualize, Synthesize, Formulate, Test, Demonstrate Acknowledgements The authors would like to acknowledge Colorado Photopolymer Solutions for their laboratory assistance and use of their facilities and instrumentation. This research was funded by the Energetic Materials and Advanced Processing (EMAP) program under the direction of Katherine Guarini. Formulate FTIR Thiol Peak Conversion *Edward D. Cooke Chemist, US Army ARDEC, Explosives Research Branch 973-724-4476. Edward.d.cooke2.civ@mail.mil Unclassified. Distribution A: Approved for Public Release. Distribution is unlimited. 3

Conceptualize, Synthesize, Formulate, Test, Demonstrate Unclassified. Distribution A: Approved for Public Release. Distribution is unlimited. Explosive Light-Cured Binders Optimized with JMP Edward D. Cooke*, Melissa N. Jablonski, Eric R. Beckel, Alexander J. Paraskos Background Secondary explosives are loaded into munition casings via three methods: melt poured, pressed, and cast cured. Cast cured explosives are composites of solid nitramines and polymeric binders. The binders consist of multiple ingredients that chemically cure to produce a rubbery composite material. Novel engineering applications have developed a need for a cast cure binder that cures when exposed to light. In an attempt to employ “Click Chemistry”, a novel, energetic pre-polymer was designed with an alkyne terminus capable of curing with a thiol cross linker in the presence of a photoinitiator and light source. Prior to incorporation into an explosive, this binder system required robust evaluation in order to fully understand the reaction chemistry and resulting material properties. Due to limited pre-polymer availability, a designed experiment was selected to direct such an evaluation. Design and Execution The continuous factors affecting the cure chemistry and cured product properties included the thiol to alkyne ratio, photoinitiator concentration, and light intensity. An additional categorical factor of “thiol type” was also examined. A sequential DOE approach was used to screen these factors in a total of 22 runs. A half fractional factorial design with centers was initially run to identify the main effects and interactions that were active in the model and to test for model curvature. This was followed up with an I-optimal augmentation focused on breaking alias chains and modeling the curvature to determine the optimal binder ingredients and curing conditions for the binder system. 10 gram samples of binder were mixed according to the DOE parameter settings. Real Time Fourier-Transform Infrared spectroscopy (RT-FTIR) during light exposure was performed in triplicate to gather information about the cure kinetics and chemical conversions. Dog bone molds were filled, cured, and analyzed with a tensile tester to evaluate the mechanical properties. Additional responses gathered for each DOE run that are not presented include glass transition temperature, viscosity, and explosive energy. Modulus Results – Screening DOE (blue center points; curvature and aliasing) Chemistry Results FTIR analysis discovered that the thiol peak is convoluted with another molecular moiety present in the binder system resulting in two overlaid Gaussian peaks that must be separated. Additionally, the alkyne and alkene peaks are convoluted with one another, so significant post-processing of the data is required. With respect to the thiol conversion, significant interactions were identified between the type of thiol and the thiol:alkyne ratio. However, FTIR results from the fractional factorial DOE indicated that ETTMP-1300 was beginning to react prior to light exposure and was thus removed from the follow up design. Initial alkyne conversion results indicate that several factors are affecting the model, thus requiring further input data for resolution. Mechanical Results Modulus, peak stress, and strain at peak stress values were all collected from the tensile tests. Modeling the modulus data from the screening DOE identified curvature, however without additional data, the specific active quadratics cannot be identified. Similar evidence of curvature and aliasing of model terms is also seen when modeling the peak stress and strain. Conclusions A sequential DOE successfully reduced the number of experiments and material required to initially screen several factors associated with a new cast cure binder system. Preliminary results indicate that optimization is achievable within the experimental parameters established for the DOE. Extensive data manipulation brought about by the specific cure chemistry is required before final models and trade-off analysis can be conducted. Explosives Research: Conceptualize, Synthesize, Formulate, Test, Demonstrate Acknowledgements The authors would like to acknowledge Colorado Photopolymer Solutions for their laboratory assistance and use of their facilities and instrumentation. This research was funded by the Energetic Materials and Advanced Processing (EMAP) program under the direction of Katherine Guarini. Test Stress vs. Position (4 runs) *Edward D. Cooke Chemist, US Army ARDEC, Explosives Research Branch 973-724-4476. Edward.d.cooke2.civ@mail.mil Unclassified. Distribution A: Approved for Public Release. Distribution is unlimited. 4

Conceptualize, Synthesize, Formulate, Test, Demonstrate Unclassified. Distribution A: Approved for Public Release. Distribution is unlimited. Explosive Light-Cured Binders Optimized with JMP Edward D. Cooke*, Melissa N. Jablonski, Eric R. Beckel, Alexander J. Paraskos Background Secondary explosives are loaded into munition casings via three methods: melt poured, pressed, and cast cured. Cast cured explosives are composites of solid nitramines and polymeric binders. The binders consist of multiple ingredients that chemically cure to produce a rubbery composite material. Novel engineering applications have developed a need for a cast cure binder that cures when exposed to light. In an attempt to employ “Click Chemistry”, a novel, energetic pre-polymer was designed with an alkyne terminus capable of curing with a thiol cross linker in the presence of a photoinitiator and light source. Prior to incorporation into an explosive, this binder system required robust evaluation in order to fully understand the reaction chemistry and resulting material properties. Due to limited pre-polymer availability, a designed experiment was selected to direct such an evaluation. Design and Execution The continuous factors affecting the cure chemistry and cured product properties included the thiol to alkyne ratio, photoinitiator concentration, and light intensity. An additional categorical factor of “thiol type” was also examined. A sequential DOE approach was used to screen these factors in a total of 22 runs. A half fractional factorial design with centers was initially run to identify the main effects and interactions that were active in the model and to test for model curvature. This was followed up with an I-optimal augmentation focused on breaking alias chains and modeling the curvature to determine the optimal binder ingredients and curing conditions for the binder system. 10 gram samples of binder were mixed according to the DOE parameter settings. Real Time Fourier-Transform Infrared spectroscopy (RT-FTIR) during light exposure was performed in triplicate to gather information about the cure kinetics and chemical conversions. Dog bone molds were filled, cured, and analyzed with a tensile tester to evaluate the mechanical properties. Additional responses gathered for each DOE run that are not presented include glass transition temperature, viscosity, and explosive energy. Peak Stress Results – Screening DOE (Evidence of curvature and aliased terms) Chemistry Results FTIR analysis discovered that the thiol peak is convoluted with another molecular moiety present in the binder system resulting in two overlaid Gaussian peaks that must be separated. Additionally, the alkyne and alkene peaks are convoluted with one another, so significant post-processing of the data is required. With respect to the thiol conversion, significant interactions were identified between the type of thiol and the thiol:alkyne ratio. However, FTIR results from the fractional factorial DOE indicated that ETTMP-1300 was beginning to react prior to light exposure and was thus removed from the follow up design. Initial alkyne conversion results indicate that several factors are affecting the model, thus requiring further input data for resolution. Mechanical Results Modulus, peak stress, and strain at peak stress values were all collected from the tensile tests. Modeling the modulus data from the screening DOE identified curvature, however without additional data, the specific active quadratics cannot be identified. Similar evidence of curvature and aliasing of model terms is also seen when modeling the peak stress and strain. Conclusions A sequential DOE successfully reduced the number of experiments and material required to initially screen several factors associated with a new cast cure binder system. Preliminary results indicate that optimization is achievable within the experimental parameters established for the DOE. Extensive data manipulation brought about by the specific cure chemistry is required before final models and trade-off analysis can be conducted. Explosives Research: Conceptualize, Synthesize, Formulate, Test, Demonstrate Acknowledgements The authors would like to acknowledge Colorado Photopolymer Solutions for their laboratory assistance and use of their facilities and instrumentation. This research was funded by the Energetic Materials and Advanced Processing (EMAP) program under the direction of Katherine Guarini. Demonstrate Peak Stress vs. Thiol:Alkyne Ratio *Edward D. Cooke Chemist, US Army ARDEC, Explosives Research Branch 973-724-4476. Edward.d.cooke2.civ@mail.mil Unclassified. Distribution A: Approved for Public Release. Distribution is unlimited. 5