A novel strategy to improve the flame retardancy and electrical conductivity of polymethyl methacrylate by controlling the configuration of phosphorus-containing polyaniline@needle coke with magnetic field

Currently, it is still a challenge to endow polymethyl methacrylate (PMMA) with excellent electroconductivity and fire safety. In this work, we have designed a novel hybrid aiming to achieve the flame resistance and electrical conductive of PMMA by fabricating an ordered structure of the FR-PANI@Fe3O4@NC. Employing a magnetic field, the FR-PANI@Fe3O4@NC hybrid shows a beneficial configuration structure to reduce the electrical resistivity of 8.9 k Omega.cm(-1) for the PMMA composite by controlling the added volume at 20 wt%. Moreover, the PMMA composite exhibits conspicuous fire resistance with an LOI of 27.4% and a V-0 rating in the UL-94 tests. Simultaneously, combined with the regular configuration structure of FR-PANI@Fe3O4@NC hybrid, the thermal stability and fire behaviour of the PMMA composite has been improved by the plentiful char residue formation. The flame-retardant mechanism of FR-PANI@Fe3O4@NC hybrid in PMMA material has been deduced by TG-IR, FTIR, and SEM, and the results implied that the FR-PANI@Fe3O4@NC hybrid containing abundant P-N functional groups generates phosphorus-containing compounds to promote the dehydration reaction of the PMMA matrix in a condensed phase. This is beneficial to improve the flame retardancy of PMMA by the formation of a char layer, providing the shielding effect to prevent the heat transfer and flammable micro-molecules volatilisation process. Hence, the as-exploited FR-PANI@Fe3O4@NC hybrid herein is believed to expand the range of applications of PMMA materials in the advanced material field.

Automated summary

In this study, a novel hybrid FR-PANI@Fe3O4@NC was designed to achieve flame resistance and electrical conductivity of PMMA by fabricating an ordered structure. By controlling the added volume at 20 wt%, the FR-PANI@Fe3O4@NC hybrid reduced the electrical resistivity of the PMMA composite to 8.9 k Omega.cm(-1). Moreover, the PMMA composite showed significant fire resistance with an LOI of 27.4% and a V-0 rating in the UL-94 test. The FR-PANI@Fe3O4@NC hybrid improved the thermal stability and fire behavior of the PMMA composite by promoting the formation of char residue. The flame-retardant mechanism of the hybrid was deduced to involve the generation of phosphorus-containing compounds that promote the dehydration reaction of the PMMA matrix.