Hierarchical engineering of boron nitride nanosheets to reveal ignition mode of action of epoxy

Abstract

AbstractIn the manuscript, the coupled parameters to influence ignition mode of charring epoxy thermoset (EP) were systematically revealed by comparative experiments and simulation. Aiming to incorporating physical variables of heat conductivity (k), specific heat capacity (c) and chemical variable of thermal‐oxidation degradation, thermally exfoliated boron nitride nanosheets were hierarchically engineered via bioinspired manipulation. Ignition time (tig) was studied in cone calorimeter test, accompanied by the in situ temperature detection and finite‐element temperature simulation. The comparative study disclosed that the physical parameters (k and c) exerted a dominant effect at the heating stage. The thermal‐oxidation degradation took effect at the determination of composition and concentration of volatiles (pertaining to ignition temperature). The pyrolyzed depth served as the bridge to connect physical and chemical aspects. The study revealed the dominant role of physical parameters in determining tig compared with chemical parameters. The concentration of volatiles was more critical than their composition. The multi‐scale structure and property relationship was established. Additionally, the changed oxygen atmospheres exerted a significant impact on piloted ignition via tailoring chemical factor. In perspective, the work will reveal a more clear understanding and modulation of ignition safety via a rational nanoscale strategy toward thermosetting polymers.