Vinyl chloride construction materials

The chemical uses for ethylene prior to World War II were limited, for the most part, to ethylene glycol and ethyl alcohol. After the war, the demand for styrene and polyethylene took off, stimulating ethylene production and olefin plant construction. Todays list of chemical applications for ethylene reads like the WTiat s What of petrochemicals polyethylene, ethylbenzene (a precursor to styrene), ethylene dichloride, vinyl chloride, ethylene oxide, ethylene glycol, ethyl alcohol, vinyl acetate, alpha olefins, and linear alcohols are some of the more commercial derivatives of ethylene. The consumer products derived from these chemicals are found everywhere, from soap to construction materials to plastic products to synthetic motor oils. 

PVC. Poly(vinyl chloride) (PVC), a very versatile polymer, is manufactured by the polymerization of vinyl chloride monomer, a gaseous substance obtained from the reaction of ethylene with oxygen and hydrochloric acid. In its most basic form, the resin is a relatively hard material that requires the addition of other compounds, commonly plasticizers and stabilizers as well as certain other ingredients, to produce the desired physical properties for roofing use. The membranes come in both reinforced and nonreinforced constructions, but since the 1980s the direction has been toward offering only reinforced membranes. The membrane thickness typically runs from 0.8—1.5 mm and widths typically in the range of 1.5—4.6 m. 

Materials that are constructed from organic polymers such as polyethylene, polystyrene, polyisoprene (natural rubber and a synthetic elastomer) and poly(vinyl chloride) are common features of our daily lives. Most of these and related organic polymers are generated from acyclic precursors by free radical, anionic, cationic or organometallic polymerisation processes or by condensation reactions. Cyclic precursors are rarely used for the production of organic polymers. 

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

The simplest recording medium is a bilayer structure. It is constructed by first evaporating a highly reflective aluminum layer onto a suitable disk substrate. Next, a thin film (15-50 nm thick) of a metal, such as tellurium, is vacuum deposited on top of the aluminum layer. The laser power required to form the mark is dependent on the thermal characteristics of the metal film. Tellurium, for example, has a low thermal diffusivity and a melting point of 452 °C which make it an attractive recording material. The thermal diffusivity of the substrate material should also be as low as possible, since a significant fraction of the heat generated in the metal layer can be conducted to the substrate. For this reason, low cost polymer substrates such as poly (methylmethacrylate) or poly (vinyl chloride) are ideal. 

VINYL CHLORIDE. Vinyl chlonde, [CAS 75-01-4] CH2=CHC1, by virtue of the wide range of application for its polymers in both flexible and rigid forms, is a major commodity chemical in the U.S. and an important item of international commerce. Growth in vinyl chlonde production is directly related to demand for its polymers and, on an eneigy-equivalent basis, rigid polyi vinyl chlonde) (PVC) is one of the most energy-efficient construction materials available. 

Vinylidene chloride-vinyl chloride copolymers were originally developed for thermoplastic molding applications, and small amounts are still used for this purpose. Extrusion of VDC-VC copolymers is the main fabrication technique for filaments, films, rods, and tubing or pipe, and involves the same concerns for thermal degradation, streamlined flow, and noncatalytic materials of construction as described for injection-molding resins. A significant application for vinylidene chloride copolymer resins is in the... 

Cables are available in a variety of constructions and materials, in order to meet the requirements of industry specifications and the physical environment. For indoor usage, such as for Local Area Networks (LAN), the codes require that the cables should pass very strict fire and smoke release specifications. In these cases, highly flame retardant and low smoke materials are used, based on halogenated polymers such as duorinated ethylene—propylene polymers (like PTFE or FEP) or poly(vinyl chloride) (PVC). For outdoor usage, where fire retardancy is not an issue, polyethylene can be used at a lower cost. 

The construction and electrochemical response characteristics of poly (vinyl chloride) membrane sensors for donepezil HC1 are described. The sensing membranes incorporate ion association complexes of donepezil HC1 cation and sodium tetraphenyl borate (sensor 1), or phospho-molybdic acid (PMA) (sensor 2), or phosphotungstic acid (sensor 3) as electroactive materials. The sensors display a fast, stable, and near-Nemstian response over a relative wide donepezil HC1 concentration... 

Within that framework, the most effective constructions to meet existing requirements have been developed based on a variety of polymers including poly(vinyl chloride) (PVC), polyolefins, silicones, and fluoropolymers. Researchers are continually striving to develop more cost-effective compositions and cable constructions to enable replacement of more expensive materials with less expensive ones. In some cases, OEMs, cable manufacturers, and material suppliers are working to pass new standards that allow for substitution of new classes of materials or designs. 

Poly(vinyl chloride), also known as PVC, is prepared by radical polymerization to produce material composed of an average of 10,000 to 24,000 monomer units. It is atactic and therefore amorphous, but it has a relatively high Tg because of the large size of its molecules and its polar carbon-chlorine bonds. It is a rigid material and is used to make pipe, panels, and molded objects. About 68% of PVC is used in the building and construction industry. A more flexible form of PVC is produced by adding a plasticizer such as dioctyl phthalate. This is used to prepare electric wire coatings, film, and simulated leather or vinyl. ... 

Although glass containers are very suitable for Hb packaging, flexible plastic containers constructed from materials such as poly(ethylene-vinyl acetate) (EVA) are most widely used. The plastic packaging material must be carefully selected. Hemoglobin, like other proteins, is lipophilic and can facilitate extraction of low molecular weight lipophilic substances, such as the plasticizers used in poly(vinyl chloride) containers. 

Contaminants arising from contact with constructional material and protective coatings (e.g. vinyl chloride monomer, PAHs from coal tar linings, lubricants for plastic joints). 

Dental Polymers. Every year nearly a half billion dental fillings are done, and over a million dentures are constructed. Most of the materials used in each of these cases are polymeric. In addition, over 300,000 dental implants are made each year with either ceramics or polymers (1). The majority of the dental fillings and dentures are made from various copolymers of methyl methacrylate with other acrylics, although some other polymers, such as polyurethanes, vinyl chloride-vinyl acetate-methacrylate copolymers, vulcanized rubber, and epoxies, have been used to some extent. One major problem is aesthetics—the prosthesis must look natural and not discolor (by photoinduction or staining) to any great extent. 

PVC/CPE or PVCIEVA (Poly(vinyl Chloride)IChlori-nated-Polyethylene) or (Poly(vinyl Chloride)IEthylene-Vinyl Acetate Copolymer). They have impact resistance and UV stability and are used in the construction industry as siding, pipes, conduit, foamed material, and rigid sheets. 

Poly(vinyl chloride) (PVC) is the predominant plastic material consumed in building and construction it accounts for almost half of this industry s total consumption of resins. The largest PVC... 

After World War II the newer polymers such as poly (vinyl chloride), polyethylene and polystyrene could be produced in large quantities at low cost. They replaced the older polymers such as cellulose nitrate as well as some of the traditional construction materials in some applications including metals, wood, leather and glass to give both technical and economic benefits. Plentiful and inexpensive, plastics lost their previous reputation as special and valuable materials and gained that of worthless and everyday. 

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