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Full-Text Articles in Physics
One-Pot Synthesis Of Urchin-Like Fepd−Fe3O4 And Their Conversion Into Exchange-Coupled L10−Fepd−Fe Nanocomposite Magnets, Yongsheng Yu, Kewei Sun, Yuan Tian, Xingzhong Li, Matthew J. Kramer, David J. Sellmyer, Jeffrey E. Shield, Shouheng Sun
One-Pot Synthesis Of Urchin-Like Fepd−Fe3O4 And Their Conversion Into Exchange-Coupled L10−Fepd−Fe Nanocomposite Magnets, Yongsheng Yu, Kewei Sun, Yuan Tian, Xingzhong Li, Matthew J. Kramer, David J. Sellmyer, Jeffrey E. Shield, Shouheng Sun
David Sellmyer Publications
We report a one-pot synthesis of urchin-like FePd−Fe3O4 nanocomposites, spherical clusters of FePd nanoparticles (NPs) with spikes of Fe3O4 nanorods (NRs), via controlled thermal decomposition of Fe(CO)5 and reduction of Pd(acac)2. The FePd NPs with sizes between 6 and 9 nm self-aggregate into 60 nm superparticles (SPs), and Fe3O4 NRs grow on the surface of these SPs. Reductive annealing at 500°C converts the FePd−Fe3O4 into exchange-coupled nanocomposites L10−FePd−Fe with their Hc tunable from 0.8 to 2.6 kOe and Ms controlled from 90 to …
Fourier Transform Infrared Spectroscopy And Wide-Angle X-Ray Scattering: Investigations On Polypropylene–Vapor-Grown Carbon Nanofiber Composites, Mircea Chipara, John Hamilton, Alin Cristian Chipara, Tom George, Dorina Magdalena Chipara, Elamin E. Ibrahim, Karen Lozano, David J. Sellmyer
Fourier Transform Infrared Spectroscopy And Wide-Angle X-Ray Scattering: Investigations On Polypropylene–Vapor-Grown Carbon Nanofiber Composites, Mircea Chipara, John Hamilton, Alin Cristian Chipara, Tom George, Dorina Magdalena Chipara, Elamin E. Ibrahim, Karen Lozano, David J. Sellmyer
David Sellmyer Publications
Fourier transform infrared (FTIR) spectroscopy and wide-angle X-ray scattering (WAXS) investigations of isotactic polypropylene (iPP)–vapor-grown carbon nanofiber (VGCNF) composites containing various amounts of VGCNFs ranging between 0 and 20 wt %. are reported. The FTIR investigations were focused on the regularity bands of iPP. The FTIR data indicated a drop in the isotacticity index as the concentration of nanofibers was increased; this suggested a decrease in the crystallinity. WAXS measurements revealed a dominating α1 phase, with a small admixture of γ phase or mesophase. The loading of the polymeric matrix with carbon nanofibers (CNFs) did not induce significant changes …
Length Scales Of Interactions In Magnetic, Dielectric, And Mechanical Nanocomposites, Ralph Skomski, Balamurugan Balamurugan, Eva Schubert, Axel Enders, David J. Sellmyer
Length Scales Of Interactions In Magnetic, Dielectric, And Mechanical Nanocomposites, Ralph Skomski, Balamurugan Balamurugan, Eva Schubert, Axel Enders, David J. Sellmyer
Axel Enders Publications
It is investigated how figures of merits of nanocomposites are affected by structural and interaction length scales, Aside from macroscopic effects without characteristic lengths scales and atomic-scale quantum-mechanical interactions there are nanoscale interactions that reflect a competition between different energy contributions. We consider three systems, namely dielectric media, carbon-black reinforced rubbers and magnetic composites. In all cases, it is relatively easy to determine effective materials constants, which do not involve specific length scales. Nucleation and breakdown phenomena tend to occur on a nanoscale and yield a logarithmic dependence of figures of merit on the macroscopic system size. Essential system-specific differences …
Spectroscopic Investigations On Polypropylene-Carbon Nanofiber Composites: I. Raman And Electron Spin Resonance Spectroscopy, Mircea Chipara, John R. Villarreal, Magdalena Dorina Chipara, Karen Lozano, Alin Cristian Chipara, David J. Sellmyer
Spectroscopic Investigations On Polypropylene-Carbon Nanofiber Composites: I. Raman And Electron Spin Resonance Spectroscopy, Mircea Chipara, John R. Villarreal, Magdalena Dorina Chipara, Karen Lozano, Alin Cristian Chipara, David J. Sellmyer
David Sellmyer Publications
Isotactic polypropylene-vapor grown carbon nanofiber composites containing various fractions of carbon nanofibers, ranging from 0 to 20 wt %, have been prepared. Raman spectroscopy was used to analyze the effect of the dispersion of carbon nanofibers within polypropylene and the interactions between carbon nanofibers and macromolecular chains. The as-recorded Raman spectra have been successfully fitted by a linear convolution of Lorentzian lines. Changes of the Raman lines parameters (position, intensity, width, and area) of polypropylene and carbon nanofibers were analyzed in detail. The Raman spectra of the polymeric matrix—at low concentrations of nanofibers—show important modifications that indicate strong interactions between …