Ether urethane from

The monomers 26 and 27 have also been used to synthesize segmented poly(ether urethane) from poly (propylene glycol) (PPG) and 4,4 -methylene-bis(phenyliso-cyanate) (MDI) [37]. In the prepolymer method employed, MDI (2 equiv.) and PPG (1 equiv.) were allowed to react at 60 °C in the presence of 1 mol% dibutyltin... 

Segmented poly(ether urethanes) were synthesized from polypropylene glycol (PPG) and 4,4 methylene-bis(phenyl-isocyanate) (MDI), using l,l -bis(B-aminoethyl)ferrocene (1) and 1,1 -bis(B-hydroxyethyl)-ferrocene (2) as chain extenders. 

Many of the PFCs discussed above, especially FSAs and FTOHs, are often building blocks used in the creation of fluorinated polymers. Fluorinated polymers are characterized by a hydrocarbon backbone, from which PFCs are appended, typically using ester, ether, urethane or methacrylate linkages [6, 7]. It is important to note that fluorinated polymers are not the same materials as fluoropolymers (such as polytetrafluoroethylene and polyvinyl fluoride) which are typically characterized by a fluorocarbon backbone [7]. 

Most of the commercial polyurethanes are derived from the polymerization of polyesterdiols or polyetherdiols with diisocyanates giving poly(ester-urethanes) and poly(ether-urethanes). 

The first lipophilicity-activity relationship was published by Charles Richet in 1893, exactly 100 years ago. From his quantitative investigations of the toxicities of ethanol, diethyl ether, urethane, paraldehyde, amyl alcohol, acetophenone, and essence of absinthe ( ) he concluded plus Us sont solubles, mains Us sont toxiques (the more they are soluble, the less toxic they are). One year later Emil Fischer derived the lock and key model of ligand-enzyme interactions from his results on the stereospecificity of the enzymatic cleavage of anomeric glycosides. 

G. LUgadas, J. C. Ronda, M. GaUa and V. Cadiz, Poly(ether urethane) networks from renewable resources as candidate biomaterials Synthesis and characterization , Biomacromolecules, 2007,8, 686-92. 

Figure 5.1.1. Dependence for equilibrium swelling of crosslinked elastomer on the base of poly ether urethane. [Adapted, by permission, from V.Yu. Senichev in Synthesis and properties of cross-linked polymers and compositions on their basis. Russian Academy of Sciences Publishing, Sverdlovsk,1990, p.l6]...

On account of the high reactivity of the N-halogen bond removal of residual halogen from the poly(ether-urethane) after grafting is essential if the material is to be used for biomedical applications. This may readily be effected by reaction with potassium iodide (compare Schuttenbarg and... 

Fig. 16.3 Sensor responses of the capacitive sensors upon exposure to various concentrations of (a) toluene and (b) ethanol. The analyte concentrations included 500-2,500 ppm, up and down. The capacitive sensor has been coated with 1.4- im-thick polar poly(ether urethane) (PEUT) layer (Reprinted with permission from Li et al. (2007). Copyright 2007...

Preparation of Urethans. Urethans are prepared by refluxii azides in absolute alcohols. When the azide is originally prepared in ethereal solution, the solution is dried, a large excess of absolute alcohol is added, and most of the ether is removed, by distillation. The urethans are isolated by evaporation or distillation of the excess solvent. Urethans from higher alcohols, such as benzyl alcohol and cholesterol, are usually prejared from a small excess of the alcohol in toluene or xylene. 

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