Polyvinyl chloride permeability

Natural organic matter Nonpurgeable organic carbon Parts per million by volume Permeable reactive barriers Polyvinyl chloride... 

In an effort to optimize the solvent-containing passive sampler design, Zabik (1988) and Huckins (1988) evaluated the organic contaminant permeability and solvent compatibility of several candidate nonporous polymeric membranes (Huckins et al., 2002a). The membranes included LDPE, polypropylene (PP), polyvinyl chloride, polyacetate, and silicone, specifically medical grade silicone (silastic). Solvents used were hexane, ethyl acetate, dichloromethane, isooctane, etc. With the exception of silastic, membranes were <120- um thick. Because silicone has the greatest free volume of all the nonporous polymers, thicker membranes were used. Although there are a number of definitions of polymer free volume based on various mathematical treatments of the diffusion process, free volume can be viewed as the free space within the polymer matrix available for solute diffusion. 

Fig. 2. Comparison of the selectivities of neutral-carrier-modified solvent polymeric- [43] and bilayer membranes. The permeability ratios PJP (at equilibrium" (Ref. 18) as far as available) fulfilled for the glyceryl dioleate BLM s are taken from Figs. 10 and 11 in Ref. 18. Values on the SPM s were obtained using 0.1 M solutions of the aqueous chlorides and membranes of the composition 33.1 wt.% polyvinyl chloride, 66.2 wt.% dioctyl adipate, 0.7 wt.% carrier. For the macrotetrolides I2 NH( for valinomycin IZ K. ...

For liquid (e.g., solution, suspension, elixir) and semisolid (e.g., creams, ointments) dosage forms in permeable or semipermeable container closure systems, a change to an ink and/or adhesive used on the permeable or semipermeable packaging component to one that has never been used in a CDER-approved product of the same dosage form, same route of administration, and same type of permeable or semipermeable packaging component (e.g., low density polyethylene, polyvinyl chloride). 

Where possible, gas connections should be made with metal or glass tubing. Where short flexible connections are necessary, PVC (Tygon) tubing is recommended. Most plastic materials have an appreciable permeability, a 1-m length of l-in.-ID polyvinyl chloride tubing with 13-in wall thickness will allow the diffusion of about 0.8 ppm of oxygen at a flow rate of 150 mL min-1. 

PVC (polyvinyl chloride). These plastics are similar to polyethylene, but each of their units contain a chlorine atom. The chlorine atom renders PVC vulnerable to some solvents, but also makes it more resistant in many applications. PVC has extremely good resistance to oils (except essential oils) and very low permeability... 

This substance has extensive lipid solubility and is absorbed immediately by the skin. Additionally, DMM is able to penetrate many materials including plastic and rubber compounds such as latex, polyvinyl chloride, and neoprene in a matter of seconds. In permeability tests, a Silver Shield glove of a flexible, plastic-laminate, offered skin protection from DMM for 4h. This chemically resistant glove, when worn under an outer glove that is resistant to abrasion and tears, may provide limited protection for direct handling of DMM. 

The permeation for gases N2, 02, C02 is usually of the order of 1 4 20. Plastics with low permeabilities include polyvinylidene chloride, polyvinyl chloride, ethylene vinyl alcohol (if dry), nylon and PET. 

Polyvinyl chloride (PVC) is an economical thermoplastic film with good barrier properties to gases and water. Later developments of even higher barrier Saran type resins based on copolymers of vinylidene chloride and vinyl chloride produced many new packaging opportunities. These materials are still very popular today (37-39). Consideration of the structure-permeability relationships for the Saran materials in Chapter 6(40) indicates that their evolution is still continuing as better understanding of the influence of sequence distribution and even more subtle issues of chain microstructure emerge. 

RGP rigid gas-permeable RPVC rigid polyvinyl chloride... 

PL membranes are usually cast from a homogeneous solution of the dissolved solid polymer material (e.g., poly(vinyl chloride)), the liquid extractant (e.g., Aliquat 336 chloride DEHPA) and a plasticizer (e.g., dioctylphtalate n-decanol) in a suitable solvent (e.g., tetrahydrofuran) by the slow evaporation of the solvent. By increasing the concentration of the extractant the permeability of the PL membrane increases while at the same time its mechanical stability deteriorates. For example, the optimal concentration range for Aliquat 336 chloride in a polyvinyl chloride based PL membrane is between 40 and 50%. 

Available plastic films vary greatly in their efficiency as a water vapor barrier. Among the more common films, Saran (a vinyUdine chloride film from Dow Plastics) is usually considered to have about the lowest permeability, with polyethylene and cellophane running a close second. Polystyrene, polyvinyl chloride acetate copolymers, and elastomers transmit much faster, whereas ethyl cellulose is one of the fastest transmitters (3000 times higher than Saran). 

Stoikes ME, Carlson JD, Farris FF, Walker PR (1987) Permeability of latex and polyvinyl chloride gloves to fluorouracil and methotrexate. Am J Hosp Pharm 44(6) 1341-1346... 

The following results have been obtained for the carbon dioxide permeability in PVC (polyvinyl chloride) at I bar and 10 bar respectively... 

PHA solutions of various densities were used to prepare transparent flexible films. The surface properties of PHB and P(HB-co-HV) fllm scaffolds were similar to each other and to those of synthetic polyesters (polyethylene terephthalate, poly (methyl methacrylate), polyvinyl chloride, and polyethylene) (Shishatskaya 2(X)7X The scaffold s surface properties are important for cell attachment and proliferation. To enhance cell adhesion to the surface, improve the gas-dynamic properties of scaffolds, and increase their permeability for substrates and cell metabolites, the scaffolds can be treated by physical factors or by chemical reagents. Biocompatibility of PHA scaffolds has been enhanced by immobilizing collagen fllm matrices on the scaffold surface and coating with chitosan and chitosan/polysaccharides (Hu et al. 2003). 

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