Polypyrrole-interface-functionalized nano-magnetite epoxy nanocomposites as electromagnetic wave absorbers with enhanced flame retardancy

Epoxy nanocomposites reinforced with polypyrrole functionalized nano-magnetite (Fe₃O₄-PPy) showed significantly enhanced electromagnetic wave absorption performance and flame retardancy. The Fe₃O₄-PPy nanocomposites were prepared by the surface initiated polymerization method. The epoxy/(30.0 wt%)Fe₃O₄-PPy nanocomposites possess a minimum reflection loss (RL) value of-35.7 dB, which is much lower than that of either epoxy/(7.5 wt%)PPy nanocomposites with a minimum RL value of-11.0 dB or epoxy/(30.0 wt%)Fe₃O₄ with a minimum RL value of-17.8 dB at the same thickness (1.7 mm). Meanwhile, the bandwidth of epoxy/(30.0 wt%)Fe₃O₄-PPy nanocomposites for RL <-10 dB and RL <-20 dB is 4.0 GHz and 0.8 GHz, respectively. The increased interface area, eddy current loss and anisotropic energy are essentially important to achieve higher reflection loss and broader absorption bandwidth for epoxy/(30.0 wt%)Fe₃O₄-PPy nanocomposites. Moreover, the significantly reduced flammability was observed in the epoxy/(30.0 wt%)Fe₃O₄-PPy nanocomposites compared with pure epoxy. The total heat release of epoxy/(30.0 wt%)Fe₃O₄-PPy nanocomposites decreased from 25.5 kJ g^-1 of pure epoxy to just 12.3 kJ g^-1. The tensile strength of the epoxy nanocomposites was reported as well. These new nanocomposites with an enhanced electromagnetic wave absorption property and flame retardancy possess great potential for safer electromagnetic wave absorbers in the electronic industry to satisfy stringent industrial standards.