An SEM and EDS study of the microstructure of nitrate ester plasticized polyether propellants

To p robe the microstructures of ni trate est er pla sticized p olyether (NEPE) composite propellants and observe th e morphology of each constit ute in the propellant, the microstructure and elemental constitutes of NEPE propellants were investigated using scanning electron microscopy and energy dispersive X-ray spectroscopy. The ammonium perchlorate (AP) grains had a scraggy surface and were difficult to disperse uniformly. The compatibility between the AP grain s a nd the poly mer bi nder wa s poor, espe cially for large grains. T he size di stribution range of the AP and o ctogen (HMX) grai ns in prop ellants varied from several to several hundreds μm for the for mer while for the latter from s everal to s everal tens μm. Contrast ing i mages be fore and after dissolution the propellant in trichloro methane sho wed th at the degree of crosslinking of the polymer binder was low since non-crosslinked binder on the surface areas was easily removed by the solvent, and that the plasti cizer was near the HMX grains and contributed more O to the element analysis of HMX.