Membrane modifications crosslinking

Other studies of interest include the modification of polysulphone membranes using crosslinking agents, thermoelastic properties of network polymers, and the effects of coating thickness on initiator activity for oligourethane acrylates and triethylene glycol dimethacrylate. ... 

This equation is not particularly useful in practice, smce it is difficult to quantify the relationship between concentration and activity. The Elory-Huggins theory does not work well with the crosslinked semicrystalline polymers that comprise an important class of pervaporation membranes. Neel (in Noble and Stern, op. cit., pp. 169-176) reviews modifications of the Stefan-Maxwell approach and other equations of state appropriate for the process. 

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). 

Hillock, A.M.W., Miller, S.J., and Koros, W.J. (2008) Crosslinked mixed matrix membranes for the purification of natural gas effects of sieve surface modification./. Memhr. Sci., 314, 193-199. 

The presence of carboxylic, hydroxylic, and acefamido fxmctionalities in HA has provided strong incentive to many investigators to pursue its modification to improve its performance in existing applications or confer unique properties for new applications. These modifications were, for the most part, directed toward the preparation of (1) crosslinked, insoluble gels and membranes and (2) covalent conjugates with several small and chain molecules with diverse chemical, pharmaceutical, and biological activities. 

Zhang, W., Li, W., Eang, Y, and Wang, X. 2007. Maleic anhydride surface-modification of crosslinked chitosan membrane and its pervaporation performance. J. Membr. Sci. 295 130-138. 

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