Plasma Treatment of Polymer Membranes

New catalysts of hydrogen oxidation for low-temperature fuel cells are molybdenum and tungsten carbides [2, 3], For solid polymeric fuel cells the novel catalysts by plasma treatment of polymer membrane have been developed. The radicals at surface are generated. These radicals are catalysts of anodic reactions [4]... 

V.M. Kochkodan, V.K. Sharma, Graft polymerization and plasma treatment of polymer membranes for fouling reduction A review, 7 iiwvirow Sci Heal A, 47 (2012) 1713-1727. 

Figure 9-34. General sehematie of the microwave installation for plasma treatment of gas-separating polymer membranes (1) modulation system (2) power supply (3) microwave magnetron (4) plasmatron ...

Thus, relations (9-96) and (9-97) describe the influence of plasma treatment and formation of the cross-links on the permeability of polymer membranes. The size of the penetrating molecules R very strongly affects the permeability rate (9-97), which explains the strong effect of plasma treatment on the selectivity of the gas-separating membranes. 

As was pointed out in the introduction, the plasma treatment of the polymer membranes becomes an interesting issue for three reasons the technique is fast, effective, and meets most of the ecological regulations for clean technology. When plasma acts on any polymer surface, two competing processes can take place ... 

Wavhal, D. and Fisher, E. 2002. Modification of porous poly(ethersulfone) membranes by low-temperature CO2 plasma treatment J. Polym. Sci. B Polym. Phys., 40, 2473. 

Gancarz et al. [90] compared the three different approaches to modify PS membranes with AA through plasma-initiated graft polymerization (1) grafting in solution, the plasma-treated polymer membrane was exposed to air for 5 min and dipped into a deaerated aqueous solution of monomer (2) grafting in vapor phase, when Ar plasma treatment on polymers was completed, a monomer vapor was introduced into the chamber and (3) plasma polymerization of monomer vapors in a plasma reactor. It was shown that modified PS membranes prepared in a vapor phase possessed the highest flux. 

In a previous section, the effect of plasma on PVA surface for pervaporation processes was also mentioned. In fact, plasma treatment is a surface-modification method to control the hydrophilicity-hydrophobicity balance of polymer materials in order to optimize their properties in various domains, such as adhesion, biocompatibility and membrane-separation techniques. Non-porous PVA membranes were prepared by the cast-evaporating method and covered with an allyl alcohol or acrylic acid plasma-polymerized layer the effect of plasma treatment on the increase of PVA membrane surface hydrophobicity was checked [37].The allyl alcohol plasma layer was weakly crosslinked, in contrast to the acrylic acid layer. The best results for the dehydration of ethanol were obtained using allyl alcohol treatment. The selectivity of treated membrane (H20 wt% in the pervaporate in the range 83-92 and a water selectivity, aH2o, of 250 at 25 °C) is higher than that of the non-treated one (aH2o = 19) as well as that of the acrylic acid treated membrane (aH2o = 22). 

Luminous vapor treatment without depositing film (LGT) could be used to modify the surface characteristics of membranes. Type B plasma polymer also could be used for this purpose. General schemes of membrane application of LGT and LCVD are schematically depicted in Figures 34.2 and 34.3, respectively [2]. Since the luminous gas interacts with the substrate material, the selection of the membrane material and the gas to be used in these possible schemes is important, and it should not be considered that any combinations of gas and material could be used in any mode of application. 

Other Methods Examples for other methods include co-casting of a hydrophobic and a hydrophilic polymer that contains amine, imine, hydroxyl, or carboxyl groups [61,89] surface modification by oxidation with ozone or by exposure to an electron or ion-beam ultrasonic etching and UV or laser irradiation [90-92]. A variety of functional groups have been also introduced onto the membrane surfaces by applying the gas discharge techniques (plasma treatment) operated at low or ambient pressure [93,94]. 

Belfort, G. and Ulbricht, M., Surface modification of ultrafiltration membranes by low temperature plasma. I. Treatment of polyacrylonitrile, J. Appl. Polym. Sci., 56, 325, 1995. 

Influence of Non-Thermal Discharge Treatment Parameters on Permeability of Plasma-Modified Gas-Separating Polymer Membranes... 

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