Extrudable Gassy Pyrotechnic Time Delay Compositions

Abstract

A copolymer of chlorotrifluoroethylene and vinylidene fluoride was investigated to assess its viability as an oxidiser, for aluminium as the fuel, in an extrudable pyrotechnic composition for application in 3D printing. Experimental results and EKVI thermochemical modelling suggested that a fuel loading of 30 wt.% would provide the maximum energy output. DTA and TGA analysis were performed in order to ascertain processing limits. With the addition of a processing aid LFC-1 ® samples could be extruded successfully. Printing with the compositions had limited success. The high melt viscosity paired with the filament's susceptibility to excessive preheating caused the print quality to be low. Delamination did not occur due to good fusion achieved during layer deposition. With minor compositional adjustments printing quality could be improvedy.

Review of the Problems of Additive Manufacturing of Nanostructured High-Energy Materials

“…The rheology of the ink determines the printability and quality of the final product [ 70 ]. An important consequence of high suspension viscosity is excessive heating of the printed material (there is a 30 °C difference between the center and the wall of the flow [ 71 ]).…”

Progress in Additive Manufacturing of Energetic Materials: Creating the Reactive Microstructures with High Potential of Applications

“…An important consequence of the high viscosity is the excessive heating of the printed material (30°C difference between the center and wall of the polymer flow [182]). Utilization of the heat-conducting component (e. g., Al) supports the heat transfer resulting in the softening and swelling of the feeding tube and, finally, nonoptimal geometry of the article [183]. That is, the rheology of the ink determines printability and print quality [184], which have to be considered to reveal the desired RMS.…”