Study on thermal aging characteristics of micro nano BiFeO3/LDPE composites under steady magnetic field

In this paper, the anti-aging properties of composites doped with nano and micro BiFeO3 and treated with different magnetic fields were studied by scanning electron microscopy (SEM), infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and broadband dielectric spectroscopy. SEM results showed that thermal aging had a significant effect on LDPE and composites, and the effect of magnetization treatment on the structure was significantly weakened. FTIR results showed that with the increase in aging time, the carbonyl content increased, the carbonyl content of nanocomposites increased less, and the carbonyl content of micron composites increased gently. DSC results showed that the addition of BiFeO3 acted as heterogeneous nucleation agent, and the orientation of magnetic field changed the arrangement of molecular chain and improved the crystallinity of the composite. Compared with the aged LDPE, the aged composite had lower dielectric constant and loss factor. 0.2 wt% nano and micro BiFeO3/LDPE composites had significant anti-aging ability, and the dielectric constant and loss factor of the composites could be further reduced by magnetic field treatment. All the test results showed that the doping of BiFeO3 and magnetic field treatment could change the internal structure of the composite, increase the compactness of the material, and make the composite have obvious thermal aging resistance.