Ignition sensitivity and electrical conductivity of an aluminum fluoropolymer reactive material with carbon nanofillers

The safe handling of powdered energetic material composites requires an understanding of their response to electrostatic discharge (ESD) ignition stimuli. In this study, a binary composite of aluminum (Al) and polytetrafluoroethylene (PTFE) is tailored for ESD ignition sensitivity by varying the concentration of highly electrically conductive nanofillers. The goal is to understand ESD ignition response of Al + PTFE when nanofiller loadings are added to the base mixture that negligibly affect combustion but significantly alter ignition and the electrical conductivity of the mixture. Previous work has shown a correlation between electrical conductivity and ESD ignition sensitivity. The nanofillers examined include carbon nanotubes (CNT), graphene nano platelets (GNP), and combinations of CNT and GNP. Adding CNT creates an electrical conductivity percolation threshold at a lower volume fraction compared to GNP. Hence, CNT are the controlling nanofiller that creates a percolating network when a combination of CNT and GNP are used. Various mixing methods are examined including sonication techniques and dry mixing. Results show that a composition insensitive to ESD ignition became sensitive by controlling its electrical conductivity through nanofiller addition.