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We report a novel low-density polyethylene (LDPE) composite filled with nickelcoated CaCu3Ti4O12 ceramic (denoted as CCTO@Ni), prepared by a melt mixing technique, and its prominent dielectric characteristics. The effects of magnetic field treatment on the dielectric properties of CCTO@Ni/LDPE composite films with a low filler concentration of 10 vol.% were investigated. Our results show that the dielectric permittivity, loss tangent, and conductivity of the LDPE composite films initially improved and then decreased with increasing treatment time under the applied magnetic field. Magnetic field treatment for 60 min led to an ultrahigh dielectric permittivity value of 1.57 × 104, four orders of magnitude higher than that of the pure LDPE material. Our results indicate that the magnetic treatment may have induced a percolation effect and enhanced the interfacial polarization of the CCTO@Ni/LDPE composite, resulting in the observed changes in its dielectric properties. [ABSTRACT FROM AUTHOR]

The effects of nanoparticles with different shapes on the interface bond energy in a polyimide/KTa0·5Nb0·5O3 composite were investigated using molecular dynamic simulations. The simulation results showed that the bond energy of sphere particles were 20-85 kcal mol−1, whereas the bond energies of three shape nanoparticles surface atoms (cube, cylinder and cone) were 5-30 kcal mol−1. This indicated that Van der Waals force and hydrogen bonds existed between the matrix and the fillers. The bond strengths of the small nanoparticles were more than the larger nanoparticles due to the size effect. At the same doping volume fraction, the bond energy of the sphere nanoclusters was significantly larger than the ones of other shaped nanoparticles. The introduction of sphere nanoparticles and the small-sized nanoparticles has the potential to be an effective way to improve the properties of the polyimide/KTa0·5Nb0·5O3 composites. [ABSTRACT FROM AUTHOR]