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Electrical, mechanical, and thermal properties of the poly(methyl methacrylate) (PMMA) composites containing functionalized multiwalled carbon nanotubes (f‐MWCNTs) and reduced graphene oxide (rGO) hybrid nanofillers have been investigated. The observed electrical percolation threshold of FHC is 0.8 wt% with maximum conductivity of 1.21 × 10−3 S/cm at 4 wt% of f‐MWCNTs. The electrical transport mechanism and magneto resistance studied of hybrid composites have also been investigated. Progressive addition of f‐MWCNTs in rGO/PMMA composite results increase in mechanical (tensile strength and Young's modulus) and thermal (thermal stability) properties of f‐MWCNTs‐rGO/PMMA hybrid nanocomposites (FHC). The increased mechanical properties are due to the efficient load transfer from PMMA matrix to f‐MWCNTs and rGO through better chemical interaction. The strong interaction between PMMA and f‐MWCNTs‐rGO in FHC is the main cause for improved thermal stability. POLYM. ENG. SCI., 59:1075–1083, 2019. © 2019 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Electrical and thermal properties of the hybrid composites, prepared using reduced graphene oxide (rGO), multi-walled carbon nanotubes (MWCNTs), and Poly (methyl methacrylate) (PMMA) have been investigated. In this hybrid composite, the effect of rGO wt.% in MWCNTs/PMMA composite has been investigated. The investigation demonstrates that the rGO-MWCNTs/PMMA hybrid composite achieved considerable improvements in electrical properties compared to the MWCNTs/PMMA and rGO/PMMA composites. The hybrid nanocomposite exhibits a percolation threshold of around 0.743 wt.% which is less than that of MWCNTs/PMMA (pc = 0:838wt:%) and rGO/PMMA (pc = 1wt:%) composites and has a maximum conductivity of 1.546-10-1S cm-1 with a filler content of 6 wt.% rGO. The experimentally observed improved electrical and thermal properties as a result of increased rGO wt.% in MWCNTs/PMMA are attributed to a synergistic effect of MWCNTs and rGO. The experimentally observed physical properties of the rGO-MWNTs/PMMA nanocomposite suggest it as potential material for future applications. [ABSTRACT FROM AUTHOR]

The effect of Fe substitution by rare‐earth (Holmium; Ho3+) ions in CoFe2O4 (CFO) prepared by glycine nitrate process is investigated from electrical, dielectric, magnetic, and Mössbauer perspectives. The anticipated spinel cubic phase structure is confirmed by X‐ray diffractometry and Fourier transform infrared (FTIR) analysis which support the presence of a secondary phase of HoFe2O3 at higher Ho content. Field emission scanning electron microscope (FESEM) and transmission electron microscopic (TEM) micrographs confirmed that the incorporation of Ho3+ significantly reduced the grain size of the samples from 50 nm to 20 nm. The complex impedance and modulus spectroscopy are investigated as a function of frequency in the regime of 102–106Hz in the temperature range of 30–300 °C. The conduction mechanism is attributed to the hopping of both electrons and holes. Activation energies (Ea) obtained from the Arrhenius plots of the grain and the grain boundary conductions are ascribed to the hopping of charge carriers. Electrical modulus results specify the existence of the non‐Debye type of dielectric relaxation. A massive reduction in loss factor is successfully achieved. Room temperature magnetization measurements indicate a reduction in saturation magnetization and coercivity (hysteresis losses) with increasing Ho3+ content, which entails these materials to be used for magnetic data storage and magneto recording devices. [ABSTRACT FROM AUTHOR]

The effect of Fe substitution by rare‐earth (Holmium; Ho3+) ions in CoFe2O4 (CFO) prepared by glycine nitrate process is investigated from electrical, dielectric, magnetic, and Mössbauer perspectives. The anticipated spinel cubic phase structure is confirmed by X‐ray diffractometry and Fourier transform infrared (FTIR) analysis which support the presence of a secondary phase of HoFe2O3 at higher Ho content. Field emission scanning electron microscope (FESEM) and transmission electron microscopic (TEM) micrographs confirmed that the incorporation of Ho3+ significantly reduced the grain size of the samples from 50 nm to 20 nm. The complex impedance and modulus spectroscopy are investigated as a function of frequency in the regime of 102–106Hz in the temperature range of 30–300 °C. The conduction mechanism is attributed to the hopping of both electrons and holes. Activation energies (Ea) obtained from the Arrhenius plots of the grain and the grain boundary conductions are ascribed to the hopping of charge carriers. Electrical modulus results specify the existence of the non‐Debye type of dielectric relaxation. A massive reduction in loss factor is successfully achieved. Room temperature magnetization measurements indicate a reduction in saturation magnetization and coercivity (hysteresis losses) with increasing Ho3+ content, which entails these materials to be used for magnetic data storage and magneto recording devices. [ABSTRACT FROM AUTHOR]