Polyvinyl chloride chemically into

Chemical/Physical. In a laboratory experiment, it was observed that the leaching of a vinyl chloride monomer from a polyvinyl chloride pipe into water reacted with chlorine to form chloroacetaldehyde, chloroacetic acid, and other unidentified compounds (Ando and Sayato, 1984). 

While not mandatory from regulatory guidehnes, much research has been carried out to investigate the extractability of plastic additives in contact with a variety of pharmaceutical formulations, mainly those for parenteral use. The research concentrates on the extractability of plasticizer phthalates, mainly di-2-ethylhexylphthalate (DEHP) from polyvinyl chloride (PVC) into the blood, blood components, and infusion solutions. The purpose for these studies lies in its, up to now, controversial hazardous effects on humans. The amount of additive necessary to turn rigid PVC into a flexible material (40% m/m) and the absence of chemical bonds between the polymer and the plasticizer make it a potentially extractable species. 

A vast number of polymer compounds are available commercially. Generally they are known by their polymer type in full or abbreviated (e.g., acrylic, polyvinyl chloride or PVC, high density polyethylene or HDPE), and frequently by a manufacturer s trade name. There is little standardisation into classes based on chemical composition or physical performance, as there is for metals. In reality, a particular chemical composition does not fully define the physical properties, while each class of performance properties can be met by a range of competing polymer types. The current trend is towards further diversification polymer compounds are increasingly being tailored to a particular application. Only in industries where recycling is an issue is there pressure for a more limited number of polymers, which can be identified and separated at the end of product life. 

Polyvinyl chloride is processed into a number of forms by including additives. Additives are used to vary the properties of PVC so that it can be made soft and flexible or hard and rigid. Additives are also used to inhibit decomposition as a result of exposure to sunlight, ozone, and chemicals. Plasticizers are the primary additive included in PVC materials. Di(2-ethylhexyl) phthalate (DEHP) and a host of other phthalates are the most common plasticizers. Plasticizers impart flexibility, thermal stability, strength, and resilience to PVC compounds. PVCs without plasticizers are classified as UPVC the letters stand for unplasticized polyvinyl chloride. UPVC is rigid and used for conduit, containers, gutters, and floor tiles. Other common PVC additives are biocides, lubricants, and pigments. 

Polyvinyl chloride (PVC) had been developed by a number of chemical companies in the 1920s. The problem with this material, however, was that it lost resiliency when heated. In 1929, Waldo Semon, a chemist at BFGoodrich, found that PVC could be made into a workable material by the addition of a plasticizer. Semon got the idea of using plasticized PVC as a shower curtain when he observed his wife sewing together a shower curtain made of rubberized cotton. 

Materials with selective binding or transport properties will have a major impact on sensor design and fabrication. Selectivity in either binding or transport can be exploited for a variety of measurement needs. This selectivity can be either intrinsic, that is, built into the chemical properties of the material, or coupled with selective carriers that allow a non-selective material to be converted into a selective one (see the section on recognition chemistry). An example of the latter is the use of valinomycin as a selective carrier in a polyvinyl chloride membrane to form a potentiometric potassium ion sensor. Advances in the fields of gas separation materials for air purification and membrane development for desalinization are contemporary examples illustrating the importance of selective materials. As these materials are identified, they can be exploited for the design of selective measurement schemes. 

The incineration of DPE suits (which are made of a mixture of polyvinyl chloride, chlorinated polyethylene, resins, plasticizers, and metal stabilizers) is subject to the same dioxin emission limits at industrial incineration facilities as they are at chemical agent disposal facilities. Thus the waste feed load and incineration bum conditions for any of these chlorinated materials into incineration units may be regulated to meet air emission control requirements. These emission control limits and resulting incineration performance requirements are spelled out in the RCRA and Clean Air Act Title 5 permits for each site. 

Vinyl dispersions are fluid suspensions of special fine particle size polyvinyl chloride resins in plasticizing liquids. When the system is heated to about 350F., fusion (mutual solubilization of resin and plasticizer) takes place. The dispersion turns into a homogeneous hot melt. When the melt is cooled below 140F., it becomes a tough vinyl coating with excellent physical properties such as flexibility, abrasion resistance, chemical resistance and excellent aging. 

Plastic pipes are polymeric in nature (e.g., polyvinyl chloride). Within the pipe are traces of the monomers used in the manufacture of the pipe (e.g., vinyl chloride). In addition, there are a variety of other chemicals added during the manufacture of the pipe as lubricants to facilitate their manufacture or stabilizers to prevent the breakdown of the pipe. In Europe, lead has been used as the stabilizer for pipes, whereas various organic tin compounds have been utilized in the United States. Lead is widely recognized as being toxic. Inorganic tin has a very limited toxicity, but this is not the form of tin that is used. Some of the organic tin compounds are potent nervous system toxins (e.g., trimethyl or triethyl tin), while others appear to adversely affect the immune system (dioctyl tin). The forms of tin used in polyvinyl chloride pipe, however, are primarily monomethyl and dimethyl tin, which are much less active as neurotoxins than the trimethyl tin. There will be some extraction of all these chemicals from the pipe when it is first put into service. However, the concentrations that are found in the water decrease sharply with continued use of the pipe. This is only partially due to the depletion of the chemical from the pipe because continuous water flow will form an impermeable barrier (e.g., calcium carbonate) on the interior of the pipe that minimizes leaching from its surface. 

The timing of the petroleum companies entry into the chemical industry determined their long-term position in the industry. The four that commercialized petrochemicals before the Japanese attack on Pearl Harbor— Standard Oil of New Jersey (Exxon by 1993), Shell, Standard Oil of California (Chevron by 1993), and Phillips—were the first movers. By the 1950s they had become the leaders in the basic feedstocks and commodity polymers such as polystyrene, polyvinyl chloride, polyethylene, and polypropylene. Those companies that entered after 1941 achieved success by focusing on specific niche products in the manner of the smaller U.S. companies. As shown in Table 1.1, these include Arco (Atlantic Refining Company), Amoco (Standard Oil of Indiana), Ashland, and BP America (acquirer of Standard Oil of Ohio). 

Following the war, Solvay expanded its output in its European factories and built new ones in Italy, Greece, and other countries. It maintained ties with all its earlier allies except, of course, with Russia, where its properties had been confiscated. Before World War I, however, it had done little to commercialize new chemicals through process technologies, as Dow had done in the United States. But it did move into polymer/petrochemicals quickly after World War II. In 1949 Solvay initiated the production of polyvinyl chloride, becoming a European leader in that basic polymer commodity. The company then entered into the production of HDPB in 1959 and PP in 1966. Shortly thereafter, it began to produce a variety of end-products in the manner of the American companies for use in both consumer and industrial chemical lines. In 1974 Solvay returned to the U.S. markets, setting up headquarters in Deer Park, Texas. By that time its soda ash and caustic soda processes had become obsolete.3 ... 

In their processible mixture, these one-component products, also belonging to physically setting adhesives, consist of two components PVC (polyvinyl chloride-) particles and plasticizers (Section 9.2.9). The solid PVC particles are disperged in the high-viscosity plasticizer. The adhesive layer formation occurs by heating (120-180 °C), when the thermoplastic PVC swells and is thus able to absorb the plasticizer (no chemical reaction ). This process is called a sol-gel process. The formerly two-phase system (sol) is turned into a single-phase system (gel) by the inclusion of the plasticizer. 

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