Magnetization, micro-x-ray fluorescence, and transmission electron microscopy studies of low concentrations of nanoscale Fe₃O₄ particles in epoxy resin

Abstract

Magnetization measurements, transmission electron microscopy (TEM), and high-resolution micro-x-ray fluorescence (-XRF) using a synchrotron radiation source (Advanced Photon Source) were used to examine Fe 3 O 4 particle agglomerates of nominally 10-nm particles at low concentrations (down to 0.03%) in thick epoxy resin samples. The magnetization measurements showed that at low concentrations (<0.5%) the magnetite particles, although closely packed in the agglomerates, did not interact magnetically. Predicated on a 2-m sample step scan, the -XRF results were compatible with the presence of spherical agglomerates due to magnetostatic attraction, and these ranged in size from 100 to several thousand nanometers, as observed in TEM measurements. At smaller step scans the resolution could be significantly improved. Thus, the synchroton -XRF method was very useful in detecting very small concentrations of particles in thick samples and could probably be used to detect particles in amounts as low as 10 −16 g.

Synthesis of epoxy ferrite nanocomposites in supercritical carbon dioxide

“…TEM of ferrite samples were recorded over JEOL 1011 (Tokyo, Japan) with a primary beam voltage of 80 kV. Electron micrographs of gold coated, longitudinal sections of samples were scanned at 1000Â magnifications over LEO-435 [4,5,18,19,21,22]. The compression strength (Â10 4 N m À2 ) of the samples was recorded on a Tinus Olson universal testing machine (UTM).…”

“…A reactive route based on impregnation or in situ polymerisation for producing polymer-based nanocomposites involves polymerisation of monomers in the presence of an initiator in suitable solvent media to produce their corresponding nanocomposites. This route has been applied to synthesise nanocomposites through either dispersing ferrite nanoparticles into epoxy resin followed by curing of epoxy resin with amine functional hardeners [4,5] or in situ polymerisation of various vinyl functional monomers in the presence of free radical initiators in organic solvents [6][7][8]. A nonreactive route of synthesis of these nanocomposites involves infusion of magnetic nanoparticles into polymer matrix in the presence of suitable organic solvents.…”

“…A literature survey revealed that although synthesis of epoxy ferrite nanocomposites, their magnetic, morphological properties and X-ray fluorescence spectra have been investigated [4,5], no efforts have been made to synthesise the proposed epoxy ferrite nanocomposites (EFNCs) through reinforcing ferrite nanoparticles at different sizes into epoxy resin in scCO 2 and to study their detailed mechanical properties. In the present investigation, efforts have therefore been made to synthesise the proposed EFNCs comprising enhanced magnetic and mechanical properties through infusing ferrite nanoparticles comprising different sized at 5.0 phr(parts per hundred of resin) concentration into diglycidylether of bisphenol A (DGEBA, 0.1 mol) in scCO 2 at 1600 psi, 85 AE 1 C for 1.0 h followed by degassing and curing the treated epoxy with triethylene tetramine (TETA, 15 phr) at 40 AE 1 C. The synthesised EFNCs were characterised through their spectra, morphology, magnetic, and mechanical properties with reference to an epoxy composite [Io], synthesised in the absence of ferrite nanoparticles under identical conditions [4,5,[18][19][20][21][22]. The synthesised EFNCs may find their applications as microwave absorbing materials [23,24] and coating materials for on-chip bondwire inductors and transformers offering a cost-effective approach to realising power systems on chip.…”

Magnetic nanocomposites based on hydrogenated epoxy resin

“…Uncoated Fe 3 O 4 nanoparticles have been used in epoxy matrices based on diglycidylether of bisphenol A (DGEBA) [43][44][45], but the cured materials showed poor dispersion of the particles and big aggregates were observed even at low particle loading. The use of silanized Fe 3 O 4 particles seems to improve dispersion, at least in photocurable epoxy formulations [46].…”

Studies on γ‐Fe2O3–high‐density polyethylene composites and their additives

“…[12][13][14][15][16] Such properties can be measured in extremely dilute suspensions. For technical applications, one needs a dense body composed of nanoparticles that can be handled while still exhibiting the special "nano" properties.…”