Cement epoxy

Epichlorohydnn is the common name of an industrial chemical used as a component in epoxy cement The molecular formula of epichlorohydnn is C3H5CIO Epichlorohydnn has an epoxide functional group it does not have a methyl group Write a structural formula for epichloro hydrin... 

The working electrode, in the form of a rectangle of thin foil, c. 20 pm thick, is glued to a piezo-electric ceramic element of the same lateral dimensions. Both the piezo element and the edge of the working electrode arc then isolated from the electrolyte with inert epoxy cement. The essence of the piezo-electric effect is that if the ceramic element is deformed in any way, a... 

While we have not yet carried out detailed kinetic measurements on the rate of photocorrosion, our impression is that the process is relatively insensitive to the specific composition of the strontium titanate. Trace element compositions, obtained by spark-source mass spectrometry, are presented in Table I for the four boules of n-SrTi03 from which electrodes have been cut. Photocorrosion has been observed in samples from all four boules. In all cases, the electrodes were cut to a thickness of 1-2 mm using a diamond saw, reduced under H2 at 800-1000 C for up to 16 hours, polished with a diamond paste cloth, and etched with either hot concentrated nitric acid or hot aqua regia. Ohmic contacts were then made with gallium-indium eutectic alloy, and a wire was attached using electrically conductive silver epoxy prior to mounting the electrode on a Pyrex support tube with either epoxy cement or heat-shrinkable Teflon tubing. 

While unaffected by water, styrofoam is dissolved by many organic solvents and is unsuitable for high-temperature applications because its heat-distortion temperature is around 77°C. Molded styrofoam objects are produced commercially from expandable polystyrene beads, but this process does not appear attractive for laboratory applications because polyurethane foams are much easier to foam in place. However, extruded polystyrene foam is available in slabs and boards which may be sawed, carved, or sanded into desired shapes and may be cemented. It is generally undesirable to join expanded polystyrene parts with cements that contain solvents which will dissolve the plastic and thus cause collapse of the cellular structure. This excludes from use a large number of cements which contain volatile aromatic hydrocarbons, ketones, or esters. Some suitable cements are room-temperature-vulcanizing silicone rubber (see below) and solvent-free epoxy cements. When a strong bond is not necessary, polyvinyl-acetate emulsion (Elmer s Glue-All) will work. 

C. Epoxy ROSins. The epoxy resins are thermosetting plastics which have great strength and the ability to form tenacious bonds with most surfaces. Furthermore, the cured resin is resistant to many solvents and chemicals. (Some epoxy resins are decomposed by acetic acid, and all are attacked by very strong oxidizing agents.) Because of this combination of properties, epoxy cements are frequently used to bond metal, glass, wood, and plastics. 

Clear polyester sheet stock and rods are available13 and, like reinforced polyester plastic, may be drilled, sawed, and machined. This clear plasic is harder than poly(methyl methacrylate) and much more solvent resistant than either po-lyfmethyl methacrylate) or polystyrene. As with all thermosetting plastics, it may not be heat-formed or solvent-bonded. However, bonding with epoxy cements is satisfactory. This plastic is claimed to give continuous service at 80°C and intermittent service up to 150°C. 

Fig. 1.12. Assembly of a filter cannula or Green filter. (a) A piece of glass capillary tubing, which has been blown open and fire-polished to form a lip on one end, is attached to the cannula with epoxy cement, (b) Filter paper is folded over the glass capillary and secured with wire.

Fig. 9.1. Multipurpose tensimeter. Since the standard taper joint is positioned close to the manometer, the joint is close to the balance point of the apparatus. The tensimeter is best supported by clamping at the taper joint and by resting the bottom of the tensimeter on a piece of foam in a small dish which in turn is supported by a ring clamp. The brace between the left arm of the manometer and the joint is held in place with epoxy cement and adds stability to the apparatus. The tensimeter is Tilled with mercury in the same manner as a U-manometer (see Fig. 7.1 caption). To minimize the votume of mercury, capillary tubing is used for the bottom and part of the teft leg.

The absorption cell was made of rectangular-section Plexiglas of dimensions 17 cm x 3.3 mm x 5 mm (the 5 mm section being mounted vertically) (see Fig. 7.2). The cell had an internal volume of 2.8 ml and two quartz windows were attached to its ends with epoxy cement. The cell was fixed on a metal support, which in turn was fitted to the burner support hole. The inlet and outlet ports (2 mm id) were about 2 mm from each end of the absorption cell. A windowless cell with similar dimensions was also made, but the inlet port was in the middle of the cell. 

Carbon electrodes. The vitreous carbon electrode usually is fabricated by sealing a plug or disk, but from a thick sheet of glassy carbon, into a glass tube with epoxy cement. The surface of the electrode is then polished until it is bright and smooth. No further treatment is necessary. 

Figure 5.38 illustrates a rotated disc electrode that is surrounded by a concentric shell of light wires sealed in epoxy cement. Products produced electro-chemically at the disc electrode are swept past the light wires, and their spec-tram is recorded by slowly scanning with the monochromator.139... 

The situation for organic solvents is less satisfactory, however. In my experience, all commercial cells depend at some point on epoxy cement which simply does not hold up to continuous exposure to many organic solvents. As shown in Figure 4, we have... 

As mentioned earlier, photochemical diodes489 can be either of the Schottky type, involving a metal and a semiconductor, or a p n junction type, involving two semi conductors (which can be the same, i.e., a homojunction or different, a heterojunc tion). Only the latter type is considered in this Section involving two irradiated semi conductor/ electrolyte interfaces. Thus n Ti02 and p-GaP crystal wafers were bonded together (through the rear Ohmic contacts) with conductive Ag epoxy cement.489 The resultant heterotype p n photochemical diode was suspended in an acidic aqueous... 

The glass slides and spacers should be sandwiched together and the two long lateral sides sealed using an epoxy cement such as Torr Seal or Kwik. To ensure a uniform spacing, the slides should be evenly clamped between two flat 0.5"-wide bars while the epoxy dries. The edges of the slides should first be scraped with a razor blade to remove any... 

Other less sophisticated evaporation techniques are, for instance, the wrapping of W cods with Pt wire. Only small amounts of Pt can be vaporized, because alloying with the hot W occurs. The problem is also found with electrodeposited Rh on W coils. Other metal powders like Ru can be glued on W wires with epoxy cement. Slow annealing drives off the carbonaceous residue leaving Ru coated on W. The... 

In low temperature studies, it is preferable to mount the crystal in a flow cell [215]. This permits the gradual change of cryoprotectant concentration as the temperature is lowered and substrate is introduced into the crystal. A quartz capillary is attached to a brass support by epoxy cement and a tight-fitting polyethylene tube sealed to the bottom of the capillary. The capillary is filled with protein mother liquor solution. The crystal is introduced to the top and allowed to settle either on to a bed of pipe cleaner fibres placed on top of the polyethylene tube as support or on to a support made by previously introducing a constriction into the quartz capillary. The crystal may be secured further by additional fibres. The inlet polyethylene tube is sealed to the top of the capillary. The inlet and outlet tubes are then connected to the reservoir and sink, respectively (Fig. 13). 

Figure 11C is a very inexpensive, disposable cell design, suitable for flat specimens. A short (5-10 mm) section of plastic or glass tubing is cut and mounted to a glass microscope slide with epoxy cement or hot-melt... 

This solution is transferred to a 50-mL electrolytic cell. The electrolytic cell is prepared by drilling two small holes on opposite sides of a 50-mL polyethylene beaker 5 mm from the bottom of the beaker and cementing two platinum wires in the holes using epoxy cement. The platinum wires should be approximately parallel and separated by 3-5 mm. 

Initially, 1.60 g [C(NH2)3] 2 [Pt(CN)4] rxr O is dissolved in 5 mL concentrated HF (28.9 M) in a 50-mL polyethylene beaker. The solution is transferred to an electrolysis cell which is constructed from a polyethylene beaker with two holes drilled 2 cm beneath the top of the solution. Two platinum wires 25 mm long are cemented in the two holes with epoxy cement and separated by 5 mm to form the electrodes. A constant potential is applied to the electrodes using a 1.5-V dc source.10 Crystal growth is observed anytime between 1 and 5 days. One week after initial crystal formation, the crystals are suction filtered through a plastic funnel using Whatman qualitative filter paper. The material is then washed with two 5-mL portions of cold water and allowed to air dry. The yield is 1.46 g (80%) based on [C(NH2)3] 2 [Pt(CN)4] xH20 being anhydrous. 

As in the chemical method, 1.55 g (3.59 mmole) K2[Pt(CN)4]-3H20 is dissolved in 6 mL water. KF (anhydrous) (1.51 g, 26.0mmole)is added and the KF dissolves leaving a fine, white suspension. Finally, 3 mL concentrated HF(aq) (24 M) is added to acidify the solution and promote solution of the white suspension. The clear solution is then transferred to the electrolytic cell, which consists of a 50-mL polyethylene beaker with two small opposing holes drilled 6 mm from the bottom. Two platinum electrodes 25 mm in length are held in place using epoxy cement and with the electrode tips separated by 2 mm. 

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