Membrane preparation copolymerization

The VBTAC monomer was insoluble in acetone despite the solubility of both reactants. The product was thus cleaned and purified with several washes in acetone, after which it was filtered and dried. The product purity was greater than 98% after the acetone washes based on NMR analyses. The functionalized monomer was stored in a dark chemical refrigerator and the same batch was used throughout the studies. The VBTAC monomer was copolymerized with VBC as described in the membrane preparation section of this article. The reaction is represented in Figure 5. 

Acrylonitrile based membranes were also used in acetic acid-water separation. Lee and Oh [11] copolymerized 4-vinylpyridine with acrylonitrile in order to prepare a membrane for the dehydration of water-acetic acid mixture by pervaporation. Yoshikava et al. [25] reported that membranes prepared from poly (acrylic acid-co-acrylonitrile)... 

Figure 4.19 Transmission electron micrograph of a cross-section of the precursor membrane for cation exchange membrane [copolymer membrane prepared from styrene and divinylbenzene in the presence of poly(vinyl chloride)]. A pasty mixture containing a higher content of monomer mixture than NEOSEPTA CL-25T was heated to soak the monomers into the poly(vinyl chloride) particles before copolymerization.

Commercial EVAL hollow-fiber membranes prepared via the copolymerization of ethylene and vinyl alcohol have been recently explored for protein immobilization. L-Histidine has been coupled onto EVAL-fibers activated with epichlo-rohydrin or butanediol diglycidyl ether to prepare an affinity support for immunoglobulin G (IgG) purification [58]. Furthermore, histidine-immobilized hollow-fiber membranes have been employed for endotoxin removal from... 

Membranes prepared by copolymerization and subsequent leaching of the polymeric pore former (see Table 1) showed remarkably high selectivities for J02 in competitive experiments with Ni +, Cd " ", Zn, and Cu at quite high fluxes.This hadbeen explained by a selective binding of uranyl ion to imprinted sites along channels that span the membrane [93]. 

Liu J, Teo WK, Chew CH, Gan LM. Nanofiltration membranes prepared by direct microemulsion copolymerization using poly(ethylene oxide) macromonomer as a polymerizable surfactant. J Appl Polym Sci 2000 77 2785-2794. 

The polymers obtained by this copolymerization [103] show weight average molecular weights upto 2 x 10. Such functionalized copolyethers are of interest for preparation of membranes with variable hydrophilicity and permeability [104]. 

The preparation and properties of a novel, commercially viable Li-ion battery based on a gel electrolyte has recently been disclosed by Bellcore (USA) [124]. The technology has, to date, been licensed to six companies and full commercial production is imminent. The polymer membrane is a copolymer based on PVdF copolymerized with hexafluoropropylene (HFP). HFP helps to decrease the crystallinity of the PVdF component, enhancing its ability to absorb liquid. Optimizing the liquid absorption ability, mechanical strength, and processability requires optimized amorphous/crystalline-phase distribution. The PVdF-HFP membrane can absorb plasticizer up to 200 percent of its original volume, especially when a pore former (fumed silica) is added. The liquid electrolyte is typically a solution of LiPF6 in 2 1 ethylene carbonate dimethyl car-... 

Two comprehensive reviews including functional PFAVE synthesis, copolymerization of functional PFAVE with fluorooleks (mainly TFE), investigations of the structure of the copolymers as well as their ion-exchange membrane properties were prepared by leading specialists from Asahi Glass Co.10 and by Russian specialists from the Membrane Processes Laboratory in the Karpov Research Institute of Physical Chemistry.11... 

Xing, P., Robertson, G. R, Guiver, M. D., Mikhailenko, S. D. and Kaliaguine, S. 2004. Sulfonated poly(aryl ether ketone)s containing the hexafluoroisopro-pylidene diphenyl moiety prepared by direct copolymerization, as proton exchange membranes for fuel cell application. Macromolecules 37 7960-7967. 

One of the technically and commercially most important cation-exchange membranes developed in recent years is based on perfluorocarbon polymers. Membranes of this type have extreme chemical and thermal stability and they are the key component in the chlorine-alkaline electrolysis as well as in most of today s fuel cells. They are prepared by copolymerization of tetrafluoroethylene with perfluorovinylether having a carboxylic or sulfonic acid group at the end of a side chain. There are several variations of a general basic structure commercially available today [11]. The various preparation techniques are described in detail in the patent literature. 

In addition, temperature-responsive properties of PNIPAAm have also been used in fabricating molecular ion gating membranes.37 38 In these studies, the concept of an ion gating molecular recognition membrane using synthetic host substances and a thermosensitive polymer was proposed. Figure 15.1038 illustrates the concept. The membrane was prepared by plasma graft copolymerization, which filled the pores of a porous polyethylene him with a copolymer of A -isopropyl... 

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