Ether ureas

Limited testing on chlorine sensitivity of poly(ether/amidel and poly(ether/urea) thin film composite membranes have been reported by Fluid Systems Division of UOP [4]. Poly(ether/amide] membrane (PA-300] exposed to 1 ppm chlorine in feedwater for 24 hours showed a significant decline in salt rejection. Additional experiments at Fluid Systems were directed toward improvement of membrane resistance to chlorine. Different amide polymers and fabrication techniques were attempted but these variations had little effect on chlorine resistance [5]. Chlorine sensitivity of polyamide membranes was also demonstrated by Spatz and Fried-lander [3]. It is generally concluded that polyamide type membranes deteriorate rapidly when exposed to low chlorine concentrations in water solution. 

U-1 Fluid Systems TFC-RC-100 Poly(ether/urea) (thin film composite)... 

By contrast, membranes U-1, A-2 and X-2 are all chlorine sensitive, each responding in a unique manner. U-1 is a thin film composite membrane, the active layer consisting of cross-linked poly(ether/urea) polymer. A-2 is a homogeneous aromatic polyamide containing certain polyelectrolyte groups. X-2 is a thin film composite membrane of proprietary composition. 

With this method, glucose and other sugars (e.g., galactose, fructose, pentose, mannitol, inositol) are determined by GLC of their trimethylsilyl ethers. Urea interferes with the silylation step but is conveniently removed by prior incubation of the urine with urease. A mixed-bed ion-exchange resin is used to deionize the resulting solution. 

Crystals. Bitter taste. Produces numbness of the tongue, mp 70-72. uv max (0,005% aq soln) 270 nm (E 0 395) Fredy sol in alcohol propylene glycol chloroform. At 20 one part dissolves in 85 parts water, h 11 parts ether Urea and its derivatives particularly urethan. increase the water soly. One part dissolves in 60 parts of 5% urethan soln, in 40 parts of 10% in 4,5 parts of 25%, Aq solns are stable, can be sterilized by heating, and are compatible and freely miscible with solns of sodium chloride, glucose and derivatives of barbituric and thiobarbituric acids, pH of satd aq solo about 6. LDW [n mice, rats (mg/kg) 471, 283 i.p, 990, 945 orally (Roszkowski) ... 

Versteegen RM, Kleppinger R, Sijbesma RP, Meijer EW (2006) Properties and morphology of segmented copoly(ether urea)s with uniform hard segments. Macromolecules 39 (2) 772-783... 

Octa(ethylene glycol) monododecyl ether urea and water 2011BIA... 

Figure 9 Poly(ether-urea) block copolymers phase separate after one-dimensional stacking and aggregation into nanofibres, as visualized by atomic force microscopy (AFM) phase images. (Reproduced from Ref. 34. American Chemical Society, 2006.)...

R.S. Labow, D.J. Erfle, J.P. Santerre, Elastase-induced hydrolysis of synthetic solid substrates poly(ester-urea-urethane) and poly(ether-urea-urethane), Biomaterials 17 (1996) 2381-2388. 

YilgOr, I., Mather, B. D., Unal, S., YilgOr, E., Long, T. E. (2004), Preparation of segmented, high molecular weight, aliphatic poly(ether-urea) copolymers in isopropanol. In-situ FT-IR studies and polymer synthesis. Polymer, 45, 5829-36. 

Urea, also named carbamide or carbonyl-diamide, was first synthesized by Wohler in 1828 from ammonia and cyanic acid. It is a colorless crystalline material, soluble in water and in alcohol but not in ether. Urea contains 46 percent nitrogen, the most of any ordinarily solid fertilizer material. Ammonium nitrate contains 34 percent nitrogen. Urea is not... 

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