Development of process of adding binder to HNS-IV explosive

HNS (Hexanitrostilbene) is a well-characterized energetic material that is used in a variety of aerospace, military, and industrial systems. HNS was first produced at the Naval Ordnance Laboratory to meet a requirement for a heat resistant explosive. HNS demonstrates acceptable performance in a temperature range of -320°C to +325° C. HNS is the material of choice for a number of reasons. It is an insensitive explosive will not inadvertently initiate when exposed to various environments such as electrostatic discharge, drops, friction or elevated temperature. There are different types of HNS from type I to type IV according to their particle size. The purpose of this study is to ensure physical integrity of HNS-IV and facilitate pelleting process by adding binder into the HNS-IV that is used as explosive in exploding foil initiator used as initiator in ignition systems of rocket and missile technology. There are many factors that affect the process of adding binder to explosive. In experimental studies in the context of this thesis, these factors were studied to determine the optimal experimental parameters. Experimental studies were based on 3 different parameters. These parameters were binder ratio, solvent/binder type and water/solvent ratio. In the process of adding binder to explosive, binder is dissolved in organic solvent and explosive is slurried in this solution. This mixture is added into the water and stirred rapidly. Then it is heated in order to remove solvent. The resulting powder mixture is filtered, washed, dried and pressed in order to make pellets. In experimental studies, Kel-F 800 and Viton-A polymers were used as a binder. In order to observe the effect of binder amount, these polymers were used in 1% and 3%. Kel-F 800 was chosen because of its superior performance among the binders. Kel-F, a proprietary product of the 3M Company, is a copolymer of chorotrifluoroethylene and vinylidene fluoride. Kel F is very thermally and chemically stable, has good mechanical properties at ambient temperatures and melts at about 100°C. Viton-A, a vinylidene fluoride and hexafluoropropylene copolymer, is a fluorinated polymer and fluorinated polymers have been found to be best suited for defense applications because of their chemical inertness, higher density, greater thermal stability and longer shelf life. In studies, Kel-F 800 was dissolved in methyl isobutyl ketone/isobutyl acetate solvent mixture and n-butyl acetate solvent; Viton-A was dissolved in methyl ethyl ketone solvent. 18 experiments were carried out in order to determine optimum experimental parameters. 12 pellets from each assay were obtained for use in the ignition test. The remaining powder mixture was used in SEM (Scanning Electron Microscope) analysis in order to examine the morphology of the explosive. Also chemical bonds and particle sizes of powder was examined by FTIR and particle size analysis.