Prepared from polyether

TABLE III - Properties of Elastomers Prepared from Polyether-MDI... 

TABLE III - Properties of Elastomers Prepared from Polyether-MDI (cont d.) Prepolymer (Vibrathane B-635) Cured with B.D, EG,HQEE, Polacure No. 740M, Polyol 50-1180 and Vibracure 3095. 

Barzin, J., S.S. Madaeni, H. Mirzadeh, and M. Mehrabzadeh. Effect of polyvinylpyrrolidone on morphology and performance of hemodialysis membranes prepared from polyether sulfone. Journal of Applied Polymer Science 92(6) (2004) 3804-3813. 

From the overview presented above it can be found that there are numerous methods of preparation of polymeric photocatalytic membranes. However, it should be stressed that in case of polymer membranes there is always a danger of destruction of the membrane structure by UV light or hydroxyl radicals. This risk is associated with the reactor configuration. Application of a photocatalytic membrane requires irradiation of the membrane itself in order to perform the photodecomposition of pollutants. The lowest UV resistance is exhibited by membranes prepared from polyether-sulfone (PES) and polysulfone (PSU) (Chin et al, 2006 Molinari et al, 2000). This can be attributed to the fact that PES and PSU contain sulfone groups which are highly sensitive to UV light. Other membranes exhibiting low UV resistance are those made of polypropylene (PP), polyacrylonitrile... 

Long-term fatigue and calcification testing was conducted on six flexible-leaflet prosthetic heart valves fabricated from a polyether-urethane-urea. Three valves exceeded 800 million cycles without failure, while three valves failed at 775,460 and 544 million cycles, respectively. Calcification was observed with and without associated failure in regions of high strain. Comparison was made with valves prepared from polyether-urethane. The results indicated that PU valves could achieve the durabilities required of an implantable prosthetic valve, equalling the fatigue fife of currently-available bioprosthetic valves. 14 refs. 

Sforca, M.L, Yoshida, I.V.P., and Nunes, S.P. (1999) Oiganic-inorganic membranes prepared from polyether diamine and epoxy silane. /. Memb. ScL, 159,197- 2ff7. 

Foams prepared from phenol—formaldehyde and urea—formaldehyde resins are the only commercial foams that are significantly affected by water (22). Polyurethane foams exhibit a deterioration of properties when subjected to a combination of light, moisture, and heat aging polyester-based foam shows much less hydrolytic stabUity than polyether-based foam (50,199). 

Polyethers prepared from propylene oxide are soluble in most organic solvents. The products with the highest hydroxyl number (lowest molecular weight) are soluble in water, not in nonpolar solvents such as hexane. The solubihty of 3000 molecular weight triols is high enough in solvents such as toluene, hexane, and methylene chloride that the triols can be purified by a solvent extraction process. 

Propylene oxide has found use in the preparation of polyether polyols from recycled poly(ethylene terephthalate) (264), haUde removal from amine salts via halohydrin formation (265), preparation of flame retardants (266), alkoxylation of amines (267,268), modification of catalysts (269), and preparation of cellulose ethers (270,271). 

Polyether Imides. Polyether imides (PEIs) are amorphous, high performance thermoplastic polymers that have been in use since 1982. The first commercial polyether imides were the Ultem series developed by the General Electric Co. The first, Ultem 1000 [61128-24-3] is prepared from phthahc anhydride, bisphenol A, and meta-phenylenediamine and has the following stmcture ... 

Not surprisingly a number of other poly(aryl ethers) have been prepared from aromatic dihalides not containing sulphone links. For example, a number have been prepared from difluorobenzophenone and, in general, it is found that such materials have TgS about 30-40°C lower than the corresponding sulphone polyether. In fact it is generally found that the higher Tg values are obtained with the sulphone polyethers. 

In 1975, Weber and Vogtle showed that open-chained polyethers, 2,6-pyridine-dimethanol, and ortho-xylene derivatives terminated in an 8-quinolinyl group could form stable, 1 1, crystalline complexes with a variety of metal salts. The podands were prepared from 8-hydroxyquinoline and the corresponding dihalides. A typical example is shown in Eq. (7.10). 

Deoxy-2-[ F]fluoro-D-mannose ( F-2DFM) was prepared through treatment of 201 (see Section 11,2) with F-Bu4NF(MeCN, 75°, 30 min) or K F crown ether, as reported for the cold synthesis. F-2DFM was also prepared from methyl 4,6-di-0-acetyl-3-C>-benzoyl-2-C>-triflyl-a-D-glu-copyranoside with amino(polyether)-supported, carrier-free [ F]fluoride. 

Studies have been made of the elastic (time-independent) properties of single-phase polyurethane elastomers, including those prepared from a diisocyanate, a triol, and a diol, such as dihydroxy-terminated poly (propylene oxide) (1,2), and also from dihydroxy-terminated polymers and a triisocyanate (3,4,5). In this paper, equilibrium stress-strain data for three polyurethane elastomers, carefully prepared and studied some years ago (6), are presented along with their shear moduli. For two of these elastomers, primarily, consideration is given to the contributions to the modulus of elastically active chains and topological interactions between such chains. Toward this end, the concentration of active chains, vc, is calculated from the sol fraction and the initial formulation which consisted of a diisocyanate, a triol, a dihydroxy-terminated polyether, and a small amount of monohydroxy polyether. As all active junctions are trifunctional, their concentration always... 

Owing to their improved stability towards hydrolysis and oxidation, dimer diol polyethers (and dimer diol polycarbonates) are used as soft segments in the preparation of thermoplastic polyurethanes. Polyurethanes prepared from such oleo-chemical building blocks are very hydrophobic and show the expected stability. 

Yang, L. and Macarevich, D., Preparation of glycol diesters from polyethers, US Patent 5 254 723, 1993. 

In most cases the catalytically active metal complex moiety is attached to a polymer carrying tertiary phosphine units. Such phosphinated polymers can be prepared from well-known water soluble polymers such as poly(ethyleneimine), poly(acryhc acid) [90,91] or polyethers [92] (see also Chapter 2). The solubility of these catalysts is often pH-dependent [90,91,93] so they can be separated from the reaction mixture by proper manipulation of the pH. Some polymers, such as the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers, have inverse temperature dependent solubihty in water and retain this property after functionahzation with PPh2 and subsequent complexation with rhodium(I). The effect of temperature was demonstrated in the hydrogenation of aqueous allyl alcohol, which proceeded rapidly at 0 °C but stopped completely at 40 °C at which temperature the catalyst precipitated hydrogenation resumed by coohng the solution to 0 °C [92]. Such smart catalysts may have special value in regulating the rate of strongly exothermic catalytic reactions. 

Pol30irethane chemistry began with the utilization of polyester polyols, principally prepared from diacids such as adipic acid and various diols. Later, polyester polyols were replaced by polyether polyols due to improvements in mechanical properties and moisture resistance. Polyether polyols now constitute the greater part of the volume in pol3airethane polymers [1]. 

Polyethers 101 derived from 1 were mentioned in a patent describing the synthesis and properties of epoxy resins, and linear polyethers were prepared from free 1, which was reacted with a,co-bischloroalkanes or 1,6-dibromohexane [17]. 

Many perfluoropolyethers [15, 77, 83] such as 17 [84] and 18 (Fig. 28) [84-86] have been prepared from appropriate polyethers by Lagow and co-workers using the LaMar technique and, indeed, many perfluoroethers are prepared on a commercial scale using direct fluorination technology (Exfluor, 3M) [16]. 

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