Polyvinyl chloride plasticized-flexible

In summary, the volume resistivity of polyvinyl chloride plasticized by liquid or elastomeric plasticizers, or internally plasticized by copolymerization, was intermediate between the inherent volume resistivities of the pure components and combined the contributions of each of them. The presence of ionic soluble impurities in liquid plasticizers provided mobile ions which conducted electricity and thus lowered volume resistivity. Copolymerization with 2-ethylhexyl acrylate provided an excellent balance of softness and flexibility with high volume resistivity further studies of internal plasticization by copolymerization are therefore recommended. 

Rigid polyvinyl chloride can be easily bonded with epoxies, urethanes, cyanoacrylates, and thermosetting acrylics. Flexible polyvinyl chloride parts present a problem because of plasticizer migration over time. Nitrile adhesives are recommended for bonding flexible polyvinyl chloride because of compatibility with the plasticizers used. Adhesives that are found to be compatible with one particular polyvinyl chloride plasticizer may not work with another formulation. Solvent cementing and thermal welding methods are also commonly used to bond both rigid and flexible polyvinyl chloride parts. 

HHHHHH HHHHHHHH Polyvinyl chloride (PVC) flexible hoses, floor tile, plastic pipes, vinyl siding, rain gutters... 

Plasticisers. Plasticisers are low molecular weight materials which alter the properties and forming characteristics of the plastic. An important example is the production of flexible grades of polyvinyl chloride by the use of plasticisers. 

MIR techniques have simplified obtaining infrared spectra of many materials important in packaging. These include rubber, plastics, laminations, and components of these materials that find use in pumps, sample packages, and devices. The combination of MIR and computerized pattern recognition techniques can be used for differentiating and classification of flexible packaging polymers such as polyvinyl chloride (PVC), polyvinylidene chloride (PVdC), acrylonitrile (Barex), and CTFE (Aclar) [22]. 

Polyvinyl chloride is also widely used. Rigid polyvinyl chloride is introduced to the mold in powder form. The material is chosen for durable constructions because of its chemical resistance and ease of processing. It incorporates functional additives and demolds easily. Plasticized polyvinyl chloride can be used to produce flexible parts such as balls and soft toy parts. The polyvinyl chloride is introduced to the mold as either a plastisol or powder. A plastisol is a suspension of granules in a plasticizing agent. When heated, the polymer granules absorb the plasticizer and fuse to form a cohesive, flexible material. 

Use Plasticizer to impart flexibility for polyvinyl chloride (PVC) and other vinyl polymers. 

Polyvinyl chloride can be shaped into clear, soft flexible tubing and sheets with the aid of using plasticizers such as diethylhexyl phthalate (DEHP). Polyvinyl chloride resins are used for children s toys, automobile seat covers, and for catheters used for intravenous transfusion of blood and nutrients in hospitals and homes. When DEHP was suspected of leaching out of the products, and of being a carcinogen, substitutions were developed with polyvinylacetate and polyethylene. However, these substitutes are not yet totally satisfactory, as they cannot be steam sterilized, and they are not as clear and flexible as PVC. 

Intractable polymers, such as polyvinyl chloride (PVC), may be flexibilized, to some extent, by the formation of copolymers, such as the copolymers of vinyl chloride and vinyl acetate or octyl acrylate, or by the addition of nonvolatile low-molecular-weight compounds (plasticizers) having solubility parameters similar to those of the polymer. Thus PVC is plasticized by the addition of dioctyl phthalate. The flexibility of these products is proportional to the amount of plasticizer added. Copolymers, such as the vinyl chloride-vinyl acetate copolymer, require less plasticizer to obtain the same degree of flexibility. 

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. 

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. 

Pure polyvinyl chloride alone It a rigid plastic of high volume resistivity. Addition of monomeric liquid plasticizer makes It flexible but lowers volume resistivity seriously. This loss of volume resistivity was not prevented by pre-purification of commercial resin and plasticizer, though It could be worsened by addition of Ionic soluble Impurities. Volume resistivity was surprisingly Increased by heat aging. It was not improved by use of polymeric liquid plasticizers, nor even, surprisingly, by use of nitrile rubber as plasticizer. Flexlblllzatlon without serious loss of volume resistivity was best achieved by internal plasticization by copolymerization with 2-ethylhexyl acrylate. Further studies are needed to explain these observations and to optimize the use of Internal plasticization In this way. 

Nevertheless, it would seem reasonable that, in the absence of any liquid plasticizer medium at all, mobility of ionic impurities would be reduced to such a low level that volume resistivity would remain high. For example, it is well known that polyvinyl chloride can be blended with nitrile rubber, such as Goodrich Hycar 1032 butadiene/acrylonitrile copolymer, and such polyblends are quite soft and flexible without the use of any liquid plasticizer at all (Table VII). 

Finally, polyvinyl chloride may be internally plasticized by copolymerization with flexibilizing comonomers such as 2-ethylhexyI acrylate, and these internally plasticized copolymers may be quite as soft and flexible as conventional externally plasticized polyvinyl chloride, without the use of any added plasticizer (J). 

Phosphites. The phosphates, second only to phthalates in production volume, are favored for flame resistance and low volatility. Tricresyl phosphate (mixed meta and para isomers) is the most popular it is used in polyvinyl chloride and in nitrocellulose lacquers. Resins plasticized with tricresyl phosphate are deficient in low-temperature flexibility. Diphenyl cresyl phosphate and triphenyl phosphate are other examples, the former for polyvinyl chloride, the latter for cellulose acetate. Diphenyl-2-ethylhexylphosphate is preferred to tricresyl phosphate in polyvinyl chloride where its low toxicity and improved low-temperature flexibility are required. Tn(2-elliylliexyl)-phosphale is outstanding among phosphates used in polyvinyl chloride with respect to low-temperature flexibility in flame- and oil resistance, however, it is inferior to tricresyl phosphate. Tri(butoxvethyl)phosphate finds some use in synthetic rubber. 

Polychloroethene (polyvinyl chloride), as usually prepared, is atactic and not very crystalline. It is relatively brittle and glassy. The properties of polyvinyl chloride can be improved by copolymerization, as with ethenyl ethanoate (vinyl acetate), which produces a softer polymer ( Vinylite ) with better molding properties. Polyvinyl chloride also can be plasticized by blending it with substances of low volatility such as tris-(2-methylphenyl) phosphate (tricresyl phosphate) and dibutyl benzene-1,2-dicarboxylate (dibutyl phthalate) which, when dissolved in the polymer, tend to break down its glasslike structure. Plasticized polyvinyl chloride is reasonably flexible and is widely used as electrical insulation, plastic sheeting, and so on. 

The mechanical admixture of low molecular weight monomers into polymers normally in the glassy state at room temperature in order to increase the flexibility and softness of the polymer has great technical importance. Thus, such plasticizers as di-2 ethyl n-hexyl phthalate are frequently incorporated into polyvinyl chloride, homopolymer or copolymer, to increase the flexibility and commercial value of this resin. Cast (1953) as well as Hellwege, Knappe and Semjonow (1959) have... 

Polyvinyl chloride (PVC) clear, flexible plastics (photo album sheets),... 

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