A study of the fracture surface of cured epoxy resin

1983 ◽  
Vol 41 ◽  
pp. 34-35
Author(s):  
V. B. Gupta ◽  
L. T. Drzal ◽  
Y. L. Chen
Keyword(s):  
Electron Microscopy ◽  
Epoxy Resin ◽  
Size Distribution ◽  
Epoxy Resins ◽  
Crosslink Density ◽  
Fracture Behavior ◽  
Fracture Pattern ◽  
Area Of Interest ◽  
Transmission Electron ◽  
Wide Size Distribution

The dependence of the fracture behavior of cured epoxy resin on its morphology is an area of interest and controversy. It is believed that the resin is heterogeneous, comprising spherical entities of high crosslink density in a matrix of relatively lower crosslink density. These heterogeneities have quite a wide size distribution, predominantly in the 10 to 50nm range and are believed to be aggregates of a few elementary entities of around 5nm in diameter. Since the fracture pattern has been observed to be around the boundary of the aggregate rather than through it, it is important to understand how these larger entities influence the fracture behavior. Hence the present study was designed to map the size distribution of aggregates which will henceforth be referred to as nodules. Although it has been pointed out that scanning electron microscopy is more suited for the study of polymer fractography than transmission electron microscopy, there has been a much greater use of TEM employing the replica method in morphological investigations of cured epoxy resins. It will be shown here that if suitable specimens are used, the morphology of cured epoxy resins can be studied with SEM.

Epoxy Resin Embedment

1968 ◽  
Vol 26 ◽  
pp. 100-101
Author(s):  
J. G. Adams ◽  
M. M. Campbell ◽  
H. Thomas ◽  
J. J. Ghldonl
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Epoxy Resin ◽  
Light Microscope ◽  
Epoxy Resins ◽  
Image Contrast ◽  
Tissue Preservation ◽  
Resin System ◽  
Excellent Quality

Since the introduction of epoxy resins as embedding material for electron microscopy, the list of new formulations and variations of widely accepted mixtures has grown rapidly. Described here is a resin system utilizing Maraglas 655, Dow D.E.R. 732, DDSA, and BDMA, which is a variation of the mixtures of Lockwood and Erlandson. In the development of the mixture, the Maraglas and the Dow resins were tested in 3 different volumetric proportions, 6:4, 7:3, and 8:2. Cutting qualities and characteristics of stability in the electron beam and image contrast were evaluated for these epoxy mixtures with anhydride (DDSA) to epoxy ratios of 0.4, 0.55, and 0.7. Each mixture was polymerized overnight at 60°C with 2% and 3% BDMA.Although the differences among the test resins were slight in terms of cutting ease, general tissue preservation, and stability in the beam, the 7:3 Maraglas to D.E.R. 732 ratio at an anhydride to epoxy ratio of 0.55 polymerized with 3% BDMA proved to be most consistent. The resulting plastic is relatively hard and somewhat brittle which necessitates trimming and facing the block slowly and cautiously to avoid chipping. Sections up to about 2 microns in thickness can be cut and stained with any of several light microscope stains and excellent quality light photomicrographs can be taken of such sections (Fig. 1).

scholarly journals The Domain and Microstructure of Resin-Bonded Magnets

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2849
Author(s):  
Marcin Jan Dośpiał
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Size Distribution ◽  
Domain Structure ◽  
Grain Size Distribution ◽  
Exchange Interactions ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Scanning Electron

This paper presents domain and structure studies of bonded magnets made from nanocrystalline Nd-(Fe, Co)-B powder. The structure studies were investigated using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Mössbauer spectroscopy and X-ray diffractometry. On the basis of performed qualitative and quantitative phase composition studies, it was found that investigated alloy was mainly composed of Nd2(Fe-Co)14B hard magnetic phase (98 vol%) and a small amount of Nd1.1Fe4B4 paramagnetic phase (2 vol%). The best fit of grain size distribution was achieved for the lognormal function. The mean grain size determined from transmission electron microscopy (TEM) images on the basis of grain size distribution and diffraction pattern using the Bragg equation was about ≈130 nm. HRTEM images showed that over-stoichiometric Nd was mainly distributed on the grain boundaries as a thin amorphous border of 2 nm in width. The domain structure was investigated using a scanning electron microscope and metallographic light microscope, respectively, by Bitter and Kerr methods, and by magnetic force microscopy. Domain structure studies revealed that the observed domain structure had a labyrinth shape, which is typically observed in magnets, where strong exchange interactions between grains are present. The analysis of the domain structure in different states of magnetization revealed the dynamics of the reversal magnetization process.

scholarly journals Rapid Synthesis of Gold Nano-Particles Using Pulse Waved Potential in a Non-Aqueous Electrolyte

2017 ◽  
Vol 62 (2) ◽  
pp. 1389-1392
Author(s):  
J.G. Jang ◽  
J.-O. Lee ◽  
C.K. Lee
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Aqueous Electrolyte ◽  
Supporting Electrolyte ◽  
Nano Particles ◽  
Rapid Synthesis ◽  
Imidazolium Chloride ◽  
Transmission Electron ◽  
Potentiostatic Electrodeposition ◽  
Pulsed Electrodeposition

AbstractRapid synthesis of gold nanoparticles (AuNPs) by pulsed electrodeposition was investigated in the non-aqueous electrolyte, 1-ethyl-3-methyl-imidazoliumbis(trifluoro-methanesulfonyl)imide ([EMIM]TFSI) with gold trichloride (AuCl3). To aid the dissolution of AuCl3, 1-ethyl-3-methyl-imidazolium chloride ([EMIM]Cl) was used as a supporting electrolyte in [EMIM]TFSI. Cyclic voltammetry experiments revealed a cathodic reaction corresponding to the reduction of gold at −0.4 V vs. Pt-QRE. To confirm the electrodeposition process, potentiostatic electrodeposition of gold in the non-aqueous electrolyte was conducted at −0.4 V for 1 h at room temperature. To synthesize AuNPs, pulsed electrodeposition was conducted with controlled duty factor, pulse duration, and overpotential. The composition, particle-size distribution, and morphology of the AuNPs were confirmed by field-emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). The electrodeposited AuNPs were uniformly distributed on the platinum electrode surface without any impurities arising from the non-aqueous electrolyte. The size distribution of AuNPs could be also controlled by the electrodeposition conditions.

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

2000 ◽  
Vol 15 (11) ◽  
pp. 2488-2493 ◽  
Author(s):  
A. N. Thorpe ◽  
F. E. Senftle ◽  
M. Holt ◽  
J. Grant ◽  
W. Lowe ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Epoxy Resin ◽  
Magnetization Measurements ◽  
X Ray ◽  
Transmission Electron ◽  
Low Concentrations ◽  
Magnetite Particles ◽  
Spherical Agglomerates ◽  
Photon Source

Magnetization measurements, transmission electron microscopy (TEM), and high-resolution micro-x-ray fluorescence (μ-XRF) using a synchrotron radiation source (Advanced Photon Source) were used to examine Fe3O4 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-μm sample step scan, the μ-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 μ-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 Route towards Fine and Monodisperse Ni Nanoparticles via Hot-Injection Approach

2013 ◽  
Vol 393 ◽  
pp. 146-151 ◽  
Author(s):  
N.R. Nik Roselina ◽  
Aziz Azizan ◽  
Koay Mei Hyie ◽  
C.M. Mardziah ◽  
Salmiah Kasolang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Size Distribution ◽  
Reaction Rate ◽  
Fine Particles ◽  
Synthesis Temperature ◽  
Ni Nanoparticles ◽  
One Pot ◽  
Transmission Electron ◽  
Hot Injection

Manipulation of adding sequences have been found to influence the reaction rate, thus made it easier to produced controllable Ni nanoparticles. Hot-injection approach shown capability to significantly reduce the production time of Ni nanoparticles compared to the conventional one-pot synthesis. With minor modification on conventional polyol method, narrow, monodispersed and highly yield spherical nickel (Ni) nanoparticles were successfully produced at synthesis temperature of 60°C. Three mixing methods were investigated to study its efficiency towards producing rapid and narrower size distribution of Ni nanoparticles. Reduction processes were proposed each of the method. As-synthesized Ni nanoparticles were characterized with Transmission Electron Microscopy (TEM), Scanning Transmission Electron Microscopy (STEM) and Fourier transform infrared spectroscopy (FTIR) to analyze the size, morphology and interaction of reactants. Fine particles size distribution revealed that when hydrazine was first heated, reaction rate improved tremendously.

Mg(OH)2/Epoxy Resin Nanocomposite Prepared by a Novel Method

2005 ◽  
Vol 13 (5) ◽  
pp. 525-527
Author(s):  
Cheng Yiyun ◽  
Cui Ronghui ◽  
He Pingsheng
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Epoxy Resin ◽  
New Method ◽  
Resin Matrix ◽  
Epoxy Resin Matrix ◽  
Transmission Electron ◽  
Micro Emulsion ◽  
Novel Method ◽  
Micro Reactor

This study presents a new method of preparing Mg(OH)2/epoxy resin nanocomposites. An epoxy resin micro-emulsion is taken as a micro-reactor for the formation of Mg(OH)2 nano-crystals. After the reaction, the collected epoxy proved to be a composite with embedded nano-Mg(OH)2. Transmission electron microscopy (TEM) indicated that the Mg(OH)2 nano-crystals were dispersed uniformly in cured epoxy resin matrix.

Fracture behavior and deformation mechanisms of polypropylene/ethylene-propylene-diene blends

2016 ◽  
Vol 36 (7) ◽  
pp. 695-704 ◽  
Author(s):  
Yuhui Ao ◽  
Fang Feng ◽  
Huixuan Zhang
Keyword(s):  
Electron Microscopy ◽  
Deformation Mechanism ◽  
Fracture Behavior ◽  
Rubber Particle ◽  
Shear Yielding ◽  
Ethylene Propylene ◽  
Transmission Electron ◽  
Rubber Particles ◽  
The Matrix ◽  
Matrix Shear

Abstract The fracture behavior and deformation mechanism of polypropylene (PP)/ethylene-propylene-diene rubber (EPDM) were studied by scanning electron microscopy and transmission electron microscopy analyses. The deformation mechanism was investigated under different conditions. Voids were seen under all the conditions because of matrix shear yielding, indicating that rubber particle cavitation took place during the blend fracture process; moreover, the void size and density increased as the fracture surface was approached. However, the void density and extent of elongation of the rubber particles in the deformation zone decreased with increasing test speed rate. Many voids were positioned in the rubber particles, confirming that matrix shear yielding initiated by rubber particle cavitation was the main deformation mechanism during ductile fracture in the matrix.

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