Magnetic Polyolefin-based Nanocomposites

2013 ◽  
Vol 1499 ◽  
Author(s):  
Qingliang He ◽  
Suying Wei ◽  
Zhanhu Guo

ABSTRACTMagnetic polyolefin-based nanocomposites were fabricated through a facile one-pot thermal decomposition of organo-metallic precursor, i.e. Fe(CO)5 in polymer-solvent solution condition. The whole fabrication includes dissolution of polyolefin-based hosting matrix in refluxing organic solvent followed by the injection of metallic precursor to perform the in-situ thermal decomposition step. The particle sizes, morphology and dispersion quality of these in-situ synthesized magnetic nanoparticles were investigated by transmission electron microscopy (TEM). Room temperature mössbauer spectrum analysis was used to determine the species of these magnetic nanoparticles. Room temperature magnetic property investigation was utilized to further reveal the magnetic behaviors of these nanocomposites by specifying the saturation magnetization and coercive forces. Thermal gravimetric analysis (TGA) was used to determine the thermal stability of these as-prepared nanocomposites and the particle loadings. The formation mechanisms of these magnetic particles were proposed from the evidence of TEM observations and detailed evolutions are detailed as well.

2012 ◽  
Vol 512-515 ◽  
pp. 1511-1515
Author(s):  
Chun Lin Zhao ◽  
Li Xing ◽  
Xiao Hong Liang ◽  
Jun Hui Xiang ◽  
Fu Shi Zhang ◽  
...  

Cadmium sulfide (CdS) nanocrystals (NCs) were self-assembled and in-situ immobilized on the dithiocarbamate (DTCs)-functionalized polyethylene glycol terephthalate (PET) substrates between the organic (carbon disulfide diffused in n-hexane) –aqueous (ethylenediamine and Cd2+ dissolved in water) interface at room temperature. Powder X-ray diffraction measurement revealed the hexagonal structure of CdS nanocrystals. Morphological studies performed by scanning electron microscopy (SEM) and high-resolution transmission electron microscope (HRTEM) showed the island-like structure of CdS nanocrystals on PET substrates, as well as energy-dispersive X-ray spectroscopy (EDS) confirmed the stoichiometries of CdS nanocrystals. The optical properties of DTCs modified CdS nanocrystals were thoroughly investigated by ultraviolet-visible absorption spectroscopy (UV-vis) and fluorescence spectroscopy. The as-prepared DTCs present intrinsic hydrophobicity and strong affinity for CdS nanocrystals.


2011 ◽  
Vol 391-392 ◽  
pp. 225-229 ◽  
Author(s):  
Qing Hong Kong ◽  
Hong Liu ◽  
Yun Long Zhang ◽  
Yong Sheng Yan

Spindle-like bis (8-hydroxyquinoline) iron (FeQ3) complex has been synthesized with a facile method in a mixed solvent system at room temperature for 12 h. The molecular formula of the products is speculated by the C, H and N element analysis and thermal gravimetric analysis, and Fourier-transformation infrared spectroscopy was also utilized to measure its structure, which further confirm the molecular formula of the products. The observation of field emission scanning electron microscopy and transmission electron microscopy shows that the morphology of tris (8-hydroxyquinoline) iron complex is spindle-like structure. The photoluminescence of the products were also investigated. The results indicate that the photoluminescence emission of FeQ3spindles shows obvious blue shift contrasted with that of 8-hydroxyquinoline.


Alloys of Al-5% Pb and Al-5% Pb-0.5% Si (by mass) have been manufactured by rapid solidification and then examined by transmission electron microscopy. The rapidly solidified alloy microstructures consist of 5-60 nm Pb particles embedded in an Al matrix. The Pb particles have a cube-cube orientation relation with the Al matrix, and are cub-octahedral in shape, bounded by {100} Al, Pb and {111} Al, Pb facets. The equilibrium Pb particle shape and therefore the anisotropy of solid Al-solid Pb and solid Al-liquid Pb surface energies have been monitored by in situ heating in the transmission electron microscope over the temperature range between room temperature and 550°C. The ani­sotropy of solid Al-solid Pb surface energy is constant between room temperature and the Pb melting point, with a {100} Al, Pb surface energy about 14% greater than the {111} Al, Pb surface energy, in good agreement with geometric near-neighbour bond energy calculations. The {100} AI, Pb facet disappears when the Pb particles melt, and the anisotropy of solid Al-liquid Pb surface energy decreases gradually with increasing temperature above the Pb melting point, until the Pb particles become spherical at about 550°C.


2019 ◽  
Vol 55 (27) ◽  
pp. 3876-3878 ◽  
Author(s):  
Eleonora Aneggi ◽  
Jordi Llorca ◽  
Alessandro Trovarelli ◽  
Mimoun Aouine ◽  
Philippe Vernoux

In situ environmental transmission electron microscopy discloses room temperature carbon soot oxidation by ceria–zirconia at the nanoscale.


2017 ◽  
Vol 13 ◽  
pp. 2023-2027 ◽  
Author(s):  
Hao Wang ◽  
Cui Chen ◽  
Weibing Liu ◽  
Zhibo Zhu

We developed a direct vicinal difunctionalization of alkenes with iodine and TBHP at room temperature. This iodination and peroxidation in a one-pot synthesis produces 1-(tert-butylperoxy)-2-iodoethanes, which are inaccessible through conventional synthetic methods. This method generates multiple radical intermediates in situ and has excellent regioselectivity, a broad substrate scope and mild conditions. The iodine and peroxide groups of 1-(tert-butylperoxy)-2-iodoethanes have several potential applications and allow further chemical modifications, enabling the preparation of synthetically valuable molecules.


1996 ◽  
Vol 436 ◽  
Author(s):  
R.-M. Keller ◽  
W. Sigle ◽  
S. P. Baker ◽  
O. Kraft ◽  
E. Arzt

AbstractIn-situ transmission electron microscopy (TEM) was performed to study grain growth and dislocation motion during temperature cycles of Cu films with and without a cap layer. In addition, the substrate curvature method was employed to determine the corresponding stresstemperature curves from room temperature up to 600°C. The results of the in-situ TEM investigations provide insight into the microstructural evolution which occurs during the stress measurements. Grain growth occurred continuously throughout the first heating cycle in both cases. The evolution of dislocation structure observed in TEM supports an explanation of the stress evolution in both capped and uncapped films in terms of dislocation effects.


1988 ◽  
Vol 100 ◽  
Author(s):  
M. W. Bench ◽  
I. M. Robertson ◽  
M. A. Kirk

ABSTRACTTransmission electron microscopy experiments have been performed to investigate the lattice damage created by heavy-ion bombardments in GaAs. These experiments have been performed in situ by using the HVEN - Ion Accelerator Facility at Argonne National Laboratory. The ion bcorbardments (50 keV Ar+ and Kr+) and the microscopy have been carried out at temperatures rangrin from 30 to 300 K. Ion fluences ranged from 2 × 1011 to 5 × 1013 ions cm−2.Direct-inpact amorphization is observed to occur in both n-type and semi-insulating GaAs irradiated to low ion doses at 30 K and room temperature. The probability of forming a visible defect is higher for low temperature irradiations than for room temperature irradiations. The amorphous zones formed at low temperature are stable to temperatures above 250 K. Post implantation annealing is seen to occur at room temperature for all samples irradiated to low doses until eventually all visible damage disappears.


Nanoscale ◽  
2018 ◽  
Vol 10 (17) ◽  
pp. 7978-7983 ◽  
Author(s):  
Liang Cheng ◽  
Xianfang Zhu ◽  
Jiangbin Su

The coalescence of two single-crystalline Au nanoparticles on surface of amorphous SiOxnanowire, as induced by electron beam irradiation, wasin situstudied at room temperature in a transmission electron microscope.


2000 ◽  
Vol 650 ◽  
Author(s):  
A. Meldrum ◽  
K. Beaty ◽  
L. A. Boatner ◽  
C. W. White

ABSTRACTIrradiation-induced amorphization of Cd2Nb2O7 pyrochlore was investigated by means of in-situ temperature-dependent ion-irradiation experiments in a transmission electron microscope, combined with ex-situ ion-implantation (at ambient temperature) and RBS/channeling analysis. The in-situ experiments were performed using Ne or Xe ions with energies of 280 and 1200 keV, respectively. For the bulk implantation experiments, the incident ion energies were 70 keV (Ne+) and 320 keV (Xe2+). The critical amorphization temperature for Cd2Nb2O7 is ∼480 K (280 keV Ne+) or ∼620 K (1200 keV Xe2+). The dose for in-situ amorphization at room temperature is 0.22 dpa for Xe2+, but is 0.65 dpa for Ne+ irradiation. Both types of experiments suggest a cascade overlap mechanism of amorphization. The results were analyzed in light of available models for the crystalline-to-amorphous transformation and were compared to previous ionirradiation experiments on other pyrochlore compositions.


2004 ◽  
Vol 819 ◽  
Author(s):  
Randall S. Hay

AbstractMonazite (LaPO4) was indented at room temperature. Deformation twin boundaries and stacking faults were characterized by high resolution transmission electron microscopy. Kinked deformation twins were also characterized and analyzed. Three types of stacking faults associated with climb-dissociated partial dislocations were observed. Two were found on twin boundaries, and a third in the lattice. Formation mechanisms are discussed. The superimposition of stacking faults along twin boundaries during deformation twinning and the glide of climb-dissociated partial dislocations allowed by stacking fault migration are discussed. The possible relationship between the formation mechanisms for these defects and the low- temperature recrystallization and self-annealing of defects in monazite is considered.


Sign in / Sign up

Export Citation Format

Share Document