Oxygen permeability, various polymers

Many PSPs are composed of probe dyes, such as polycyclic aromatic hydrocarbons (e.g., pyrene) and coordination compounds (e.g., platinum por-phryins and ruthenium(II) polypyridyl complexes) immobilized in various gas permeable polymer films such as silicon polymer, organic glassy polymers (e.g., poly(methylmethacrylate), polystyrene), fluorinated polymers, or cellulose derivatives such as ethyl cellulose [9,10]. As probe molecules interact with polymer matrices directly, the properties of PSPs strongly depend on the properties of polymer matrices. The oxygen permeability of polymer matrix is an especially important factor for highly sensitive PSP. 

Table I. Oxygen Permeability in Polymers of Various Molecular Structures at 25 °C...

Table II.6 Permeabilities of nitrogen and oxygen in various polymers (5-10)...

From the slope of the straight line obtained from the plot of the left-hand side of Eq. (4) by changing the thickness of the membrane, the resistance of only the membrane can be obtained. Furthermore, from its reciprocal, the permeation coefficient of the membrane is obtained. Table 1 lists the permeability of oxygen for various polymer membranes in the presence of water measured by this technique [276]. A comparison is also made with the same polymer in the dry state. Judging from this result, a hydrophobic membrane such as polyethylene shows similar permeability of oxygen in the presence or absence of water. In contrast, as the hydrophilicity... 

Table 7.3. Relative Fluorescence Quantum Yield of Crystal Violet,

No amount of sterilization wiU prevent or even slow autooxidation, and there are only two defenses removal of O2 and addition of inhibitors. Oxygen barriers in food packaging are a major topic in the engineering of polymer films. The barrier properties of various polymers are very important in food applications, and many of these are multilayer polymers that have a thin layer of an impermeable polymer (such as polyacrylonitrile and ionic polymers) on a cheaper but O2-permeable polymer such as a polyolefin, which gives mechanical strength to the fikn. 

Abstract Pressure-sensitive paint (PSP) is applied to the areodynamics measurement. PSP is optical sensor based on the luminescence of dye probe molecules quenching by oxygen gas. Many PSPs are composed of probe dye molecules, such as polycyclic aromatic hydrocarbons (pyrene, pyrene derivative etc.), transition metal complexes (ruthenium(II), osumium(II), iridium(III) etc.), and metalloporphyrins (platinum (II), palladium(II), etc.) immobilized in oxygen permeable polymer (silicone, polystyrene, fluorinated polymer, cellulose derivative, etc.) film. Dye probe molecules adsorbed layer based PSPs such as pyrene derivative and porphyrins directly adsorbed onto anodic oxidised aluminium plat substrate also developed. In this section the properties of various oxygen permeable polymer for matrix and various dye probes for PSP are described. 

Finally, PSPs based on the OEP metal complexes in various cellulose derivative polymers also have been introduced. Cellulose derivative polymers such as ethyl cellulose, cellulose acetate etc., as shown in Fig. 9, also provide a mechanical strength to thin film. The oxygen permeability, diffusion constant, and solubility for oxygen for typical cellulose derivative polymers are listed in Table 1. Cellulose derivative polymer films with plasticizer tributyl phosphate (TBP) have large oxygen permeability. Cellulose acetate with TBP... 

For example, consider a soft drink or soda bottle. What are the requirements Cheap Strong enough to contain up to 2L of soda. Optically clear. And very important, a barrier for 0O2, because carbonated beverages taste flat once the concentration of carbon dioxide falls too low. Table 8-1 lists the permeability of various polymers to C02 as well as to oxygen and water vapor. 

Effect Of Molecular Structure on Polycarbonate Oxygen Permeability. Permeability measurements on a series of structurally different aromatic polycarbonates indicate a strong relationship between monomer structure and polymer permeability. A major part of this study investigated properties of polycarbonates which were prepared from variously substituted bisphenols. The polycarbonate samples are based upon bisphenol monomers which differ from 2,2-bis(4-hydroxy-... 

Table I Permeability of various polymers to carbon dioxide oxygen and...

Table 4.3 Permeability to oxygen and water vapour for various polymers ...

With the exception of packages for fresh produce, MAP trays or pouches need to be made of materials with low permeability to gases (CO2, Nj, O2). Laminates made of various combinations of polymer as PET, PVdC, PE, and polyamides such as nylons should have low oxygen permeability [175-178]. Respiration in fruits and vegetables leads to a build-up of carbon dioxide that may reduce the rate of respiration and help to prolong the shelf life of the product a reduction in the oxygen... 

The oxygen permeability and some other physical parameters of various polyvinylidene polymers are summarized below (J.Mohr and D.R. Paul, JAPS,... 

Figure 3.2 Influence of aging time on relative oxygen permeability (based on permeability after 1 h of aging) in thin films of various polymers about 400 nm thick.

Inorganic polymers such as polydimethylsiloxanes (PDMSs) have various interesting properties, e.g., high oxygen permeability, low toxicity, and biocompatibility, which are advantages as biomaterials [24]. Therefore, saccharide-PDMS hybrid would be expected to have a significant potential for biological applications. In this section, therefore, we describe... 

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