Epoxy transmission electron microscopy

High Resolution Transmission Electron Microscopy (HRTEM, Philips CM20, 200 kV) was applied to get structural and nanotextural information on the fibers, by imaging the profile of the aromatic carbon layers in the 002-lattice fringe mode. A carbon fiber coated with pyrolytic carbon was incorporated in epoxy resin and a transverse section obtained by ultramicrotomy was deposited on a holey carbon film. An in-house made image analysis procedure was used to get quantitative data on the composite. 

Transmission Electron Microscopy Transmission electron microscopy data were obtained by personnel in the Ultrastructure Laboratory at the Virginia-Maryland College of Veterinary Medicine using a JEOL lOOCX-II transmission electron microscope. Samples were imbedded in Poly-bed 812 epoxy resin and cured at 50-60°C for 2-3 days. Samples were then sectioned to between 800 and 1000 on either a Sorval MT2B or an LKB IV Ultramicrotome using glass knives and were placed on 200 mesh copper grids. 

Transmission electron microscopy (TEM) and birefringence studies of strained and/ or fractured epoxies have revealed more direct experimental evidence that molecular flow can occur in these glasses. Films of DGEBA-DETA ( 11 wt.- % DETA) epoxies, 1 pm thick, were strained directly in the electron microscope and the deformation processes were observed in bright-field TEM 73 110). Coarse craze fibrils yielded in-homogeneously by a process that involved the movement of indeformable 6-9 tan diameter, highly crosslinked molecular domains past one another. The material between such domains yielded and became thinner as plastic flow occurred. 

Siebert and Riew (4) described the chemistry of the in situ particle formation. They proposed that the composition of the particle is a mixture of linear CTBN-epoxy copolymers and crosslinked epoxy resin. The polymer morphology of the CTBN toughened epoxy systems was investigated by Rowe (5) using transmission electron microscopy by carbon replication of fracture surfaces. Riew and Smith (6) supported the... 

TEM (Transmission Electron Microscopy) analysis. This analysis was done on a Philips 420T microscope (120kV, maximum resolution 5A) equipped with an EDAX PV9900 EDS. The catalysts were ground to a powder, embedded in epoxy resin and then microtomed with a diamond l fe to obtain sections about 300A thick. Images were taken at 100 kV. Diameters of about 100 isometric-shaped Pt crystallites were measured for each sample. 

Fig. 26. Integrated SAXS intensity (arbitrary units) vs polymerization time at 50 °C for an epoxy-diamine system (DGEBA-3DCM) modified by 15 wt% of two different rubbers (ETBN and NFBN). Morphology of the particles (p-phase), as observed by transmission electron microscopy (TEM), is plotted qualitatively. Cloud-point times (tcp), determined by light transmission, and gelation times are indicated...

Transmission electron microscopy (TEM) is important to monitor cell-free sperm decondensation and nuclear formation. To prepare specimens for TEM, incubation mixture aliquots were fixed for 45 min in 2.5% (v/v) paraformaldehyde, 3.1% (v/v) glutaraldehyde, 0.02% (w/v) picric acid in 30 mAf NaHP04, pH 7.5. After fixation, samples were embedded in 2% (w/v) low-gelling-temperature agarose and postfixed for 15 min in 1% (w/v) OSO4. Samples may be dehydrated either in ethanol and propylene oxide or acetone and embedded for sectioning in Spurr s low-viscosity epoxy resin (Spurr, 1%9). Before examination, sections of about 70-nm thickness should be stained, e.g., with uranyl acetate and Reynolds lead citrate (Re)molds, 1%3). 

Microscopy. Transmission electron microscopy was performed using a Zeiss EM-10 microscope and a JEOL JEM200CX microscope operated at 80 and 2(X) kV, respectively. Samples were prepared by drying a drop of the dispersion on a carbon coated copper grid and were unstained. Cross sections of metallized tubules were obtained by embedding the tubules in epoxy (Medcast Kit/Ted Pella Inc.) according to the manufacturer s instructions. The epoxy was cured at 60 °C... 

In addition to the above, techniques such as scanning electron microscopy (SEM) are used to study the morphology of the blends of polyesters with other resins and compounded polyesters (paints), which indicate the homogeneity and phase behaviour with domain size of different components present in the system. To study the morphology of polyester-melamine or polyester-epoxy blend and their mixtures with different reinforcing agents, transmission electron microscopy (TEM) is now used along with SEM. Atomic force microscopy (AFM) may sometimes be used to study the surface structure of polyester blends. 

For transmission electron microscopy (TEM), gel samples were dehydrated in acetone, stained with osmium tetroxide, and embedded in epoxy resin. The embedded samples were cut into slices of 50-100nm thickness with an ultramicrotome LKB-V (LKB, Sweden) and examined using TEM (Hitachi H-600, Japan). 

Surface analysis such as dynamic contact angle and surface tension are used to ensure proper wetting of epoxy and the substrate. Microscopic techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM), are widely used to study morphology, fracture, and adhesion issues of cured epoxy systems. Chemical analysis techniques, such as micro-IR, X-ray photoelectron spectrometry (XPS), and secondary ion mass... 

Start and Mauritz [396] used environmental SEM-EDAX, and also AFM and transmission electron microscopy, to study the formation of organic-inorganic nanocomposites within surlyn(PE-co-methacrylate-cation forms) random copolymers. SEM-EDAX has also been used to study of thin films of Prussian blue and N-substituted polypyrroles [397], epoxy resins [399], and the cause of failure in acetal plumbing fittings caused by exposure to chlorine [400]. 

The Scanning electron microscopy (SEM) is carried out on a Philips XL-20 microscope, and the transmission electron microscopy (TEM) is performed on a Philips Tecnai-10 microscope at 100 kV. The specimens for TEM observation are prepared by embedding the samples in epoxy resin and ultramicrotoming, and mounting on a copper grid. 

Figure 4.3 Influence of morphology on the showing the final morphologies of the cured rheological behavior of epoxy resins with differ- blends. Reproduced with permission from ent content of thermoplastics (polyetherimide). Ref. [49] 1999, American Chemical Society. Transmission electron microscopy images...

---