Epoxy polyethylene

Corrosion. Anticorrosion measures have become standard ia pipeline desiga, coastmctioa, and maintenance ia the oil and gas iadustries the principal measures are appHcation of corrosion-preventive coatings and cathodic protection for exterior protection and chemical additives for iaterior protectioa. Pipe for pipelines may be bought with a variety of coatiags, such as tar, fiber glass, felt and heavy paper, epoxy, polyethylene, etc, either pre-apphed or coated and wrapped on the job with special machines as the pipe is lowered iato the treach. An electric detector is used to determine if a coatiag gap (hoHday) exists bare spots are coated before the pipe is laid (see Corrosion and corrosion control). 

POLYSTYRENE EPOXIES polyethylene BLACK polyethylene NATURAL RUBBER butyl rubber NEOPRENE RUBBER ACRYLONITRILE RUBBER polyurethanes... 

Results. Figure 1 shows the effect of the ultimate temperature of bond formation on the tensile-shear strength of the aluminum-epoxy-polyethylene composite structure described previously. It is rather obvious that at temperatures close to 100°C. the epoxy, even though its viscosity is low, has not formed a strong bond with the polyethylene, for the reason, we believe, that it has not achieved extensive interfacial contact with the polyethylene before solidification occurs. If, however, one first solidifies the epoxy at some temperature below 100°C. and then raises the temperature close to, or above, the melting point of the... 

Aluminum-epoxy-aluminum composite Aluminum-epoxy-polyethylene-epoxy-aluminum composite O Aluminum-epoxy—cross-linked polyethylene—epoxy-aluminum composite... 

The most common failure modes of these pipes are uniform corrosion (both external and internal), graphitization, and pitting under unprotected corrosion scales. Loose tubercles may cause blockage of pipes. The corrosion control of loose particles is by the addition of corrosion inhibitors, which protect the inside pipe walls or internal lining of the pipe. Other protective linings are specialty cement mortars, epoxies, polyethylene, and polyurethane. 

Rhdne-Poulenc Rhodafac Series Acrylic, Epoxy, Polyethylene, Phenolic, Polypropylene... 

Halogenated organic Great Lakes Chemicals NH-1511,NH-1197 Epoxy, Polyethylene, Polypopylene... 

Firebrake zb is used as a flame retardant, smoke and afterglow suppressant, and anti-arcing agent in polymer systems such as polyvinyl chloride, nylon, epoxy, polyethylene, polypropylene, polyesters, thermoplastic elastomers and rubbers. 

Miscellaneous. Flame-resistant cross-linked polyethylene can be made with a number of fluoroborates and antimony oxide. This self-extinguishing material may contain the fluoroborates of NH, Na", K", Ca ", Mg ", Sr ", or Ba " in amounts of 4—20% (76). Magnesium fluoroborate cataly2es the epoxy treatment of cotton fabrics for permanent-press finishes (77) (see Textiles). 

Shipment ndStora.ge. The crystalline material is shipped as a nonha2ardous material, in polyethylene-lined fiber dmms. The solution can be shipped in dmms or bulk. Suitable materials of constmction for handling ammonium thiocyanate are aluminum, 316 stainless steel, mbber, poly(vinyl chloride), and glass-reinforced epoxy. Steel, 304 stainless steel, and copper alloys should be avoided (375,376). 

Waterproof. Waterproofing barrier systems may be either hot- or cold-appHed. The hot-appHed generaUy involve a bituminous material such as asphalt used in conjunction with a reinforcing fabric such as roofing felt, cotton, or glass cloth. Cold-appHed can be bituminous or elastomeric materials either in Hquid or sheet form, with or without fabric reinforcement. Liquid elastomeric treatments include neoprene, polyurethanes, and blends of these or epoxies with bituminous materials. Among the commonly used precured elastomeric sheet materials are neoprene, polyisobutylene, EPDM mbber, and plasticized PVC. Polyethylene and PVC films and nonwoven plastic or glass fabric coated with bituminous materials also find use (78). Because these... 

Covers for the battery designs in Figures 1 and 2 are typically molded from materials identical to that of the respective case, and vent plugs are frequentiy made of molded polypropylene. Other combinations are possible, eg, containers molded of polyethylene or polypropylene may be mated with covers of high impact mbber for use in industrial batteries. After the cover is fitted over the terminal post, it is sealed onto the case. The cover is heat bonded to the case, if it is plastic it is sealed with an epoxy resin or other adhesive, if it is vulcanized mbber. Vent caps are usually inserted into the cover s acid fiU holes to faciHtate water addition and safety vent gasses, except for nonaccessible maintenance-free or recombinant batteries. In nonaccessible batteries, the vent is fabricated as part of the cover. 

The thermoplastic or thermoset nature of the resin in the colorant—resin matrix is also important. For thermoplastics, the polymerisation reaction is completed, the materials are processed at or close to their melting points, and scrap may be reground and remolded, eg, polyethylene, propjiene, poly(vinyl chloride), acetal resins (qv), acryhcs, ABS, nylons, ceUulosics, and polystyrene (see Olefin polymers Vinyl polymers Acrylic ester polymers Polyamides Cellulose ESTERS Styrene polymers). In the case of thermoset resins, the chemical reaction is only partially complete when the colorants are added and is concluded when the resin is molded. The result is a nonmeltable cross-linked resin that caimot be reworked, eg, epoxy resins (qv), urea—formaldehyde, melamine—formaldehyde, phenoHcs, and thermoset polyesters (qv) (see Amino resins and plastics Phenolic resins). 

This includes wire enamels on a base of polyvinyl formal, polyurethane or epoxy resins as well as moulding powder plastics on phenol-formaldehyde and similar binders, with cellulose fillers, laminated plastics on paper and cotton cloth base, triacetate cellulose films, films and fibres of polyethylene terephthalate. 

A somewhat similar thing happens in many polymers at the glass-rubber transition that we mentioned in Chapter 6. Below the transition these polymers are much more brittle than above it, as you can easily demonstrate by cooling a piece of rubber or polyethylene in liquid nitrogen. (Many other polymers, like epoxy resins, have low Gc values at all temperatures simply because they are heavily cross-linked at all temperatures by covalent bonds and the material does not flow at the crack tip to cause blunting.)... 

Thin coatings consist of paints and varnishes, which are applied as liquids or powdered resin with a thickness of about 0.5 mm [e.g., epoxy resin (EP) [2]]. Typical thick coatings are bituminous materials [3] and polyolefins [e.g., polyethylene (PE) [4]], thick coating resin combinations [e.g., EP tar and polyurethane (PUR) tar [2]] as well as heat-shrinkable sleeves and tape systems [5]. 

The demands on insulating materials in soil and fresh water are relatively low. Anodically evolved oxygen makes the use of aging-resistant insulating materials necessary. These consist of special types of rubber (neoprene) and stabilized plastics of polyethylene, and polyvinylchloride, as well as cast resins such as acrylate, epoxy, polyester resin and many others. 

Such compositions give good heat resistance and adhesion to unprepared metal. Adhesives based on chlorosulfonated polyethylene have also been modified by an epoxy resin [ 146]. 

Optical Properties. The optical properties of a plastic which are important are refraction, transparency, gloss and light transfer. The reader is referred to BS 4618 1972 for precise details on these terms. Table 1.9 gives data on the optical properties of a selection of plastics. Some plastics may be optically clear (e.g. acrylic, cellulosics and ionomers) whereas others may be made transparent. These include epoxy, polycarbonate, polyethylene, polypropylene, polystyrene, polysulphone and PVC. 

Preparation of 9a-Fluoro-110,17a,21-Trihydroxy-160-Methyl-4-Pregnene-3,2O-Dione 21-Acetate To a solution of 200 mg of 9(3,11(3-epoxy-1 7a,21-dihydroxy-16(3-methyl-4-pregnene 3,20-dione 21-acetate in 2 ml of chloroform and 2 ml of tetrahydrofuran in a polyethylene bottle at -60°C was added 2 ml of a 2 1 (by weight) mixture of anhydrous hydrogen fluoride and tetrahydrofuran. After 4 hours at -10°C the mixture was cooled to -60°C and cautiously added to a stirred mixture of 30 ml or 25% aqueous potassium carbonate and 25 ml of chloroform kept at -5°C. The aqueous phase was further extracted with chloroform and the latter phase washed with water and dried over magnesium sulfate. The residue on crystallization from acetone-ether gave pure 9a-fluoro-11(3,17a,21-trihydroxy-16(3-methyl-4-pregnene-3,20-dione 21-acetate. 

To approximately 1.3 g of hydrogen fluoride contained in a polyethylene bottle and maintained at -60°C was added 2.3 ml of tetrahydrofuran and then a solution of 500 mg (0.0012 mol) of 6a-fluoro-9/3,11/3-epoxy-16a-methyI-17a,21 -dihydroxy-1,4-pregnadiene-3,20-dione-2T acetate in two ml of methylene chloride. The steroid solution was rinsed in with an additional 1 ml of methylene chloride. The light red colored solution was then kept at approximately -30°C for 1 hour and at -10°C for 2 hours. At the end of this period it was mixed cautiously with an excess of cold sodium bicarbonate solution and the organic materiai extracted with the aid of additional methylene chloride. 

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