Polypyrrole-interface-functionalized nano-magnetite epoxy nanocomposites as electromagnetic wave absorber with enhanced flame retardancy
Epoxy nanocomposites reinforced with polypyrrole functionalized nano-magnetitie (Fe3O4-PPy) showed significantly enhanced electromagnetic wave absorption performance and flame retardancy. The Fe3O4-PPy were prepared by the surface initiated polymerization method. The epoxy/(30.0wt%)Fe3O4-PPy nanocomposites possess a minimum reflection loss (RL) value of -35.7 dB, which is much lower than either epoxy/(7.5wt%)PPy nanocomposites with a minimum RL value of -11.0 dB or epoxy/(30.0wt%)Fe3O4 with a minimum RL value of -17.8 dB at the same thickness (1.7 mm). Meanwhile, the bandwidth of epoxy/(30.0wt%)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 acquire higher reflection loss and broader absorption bandwidth for epoxy/(30.0wt%)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 decreased from 25.5 kJ/g of pure epoxy to just 12.3 kJ/g. The tensile strength of the epoxy nanocomposites was reported as well. These new nanocomposites with enhanced electromagnetic wave absorption property and flame retardancy possess great potential in safer electromagnetic wave absorber in electronic industry to satisfy stringent industrial standards.