Ethers urethans

Virtually all of the organo derivatives of CA are produced by reactions characteristic of a cycHc imide, wherein isocyanurate nitrogen (frequendy as the anion) nucleophilically attacks a positively polarized carbon of the second reactant. Cyanuric acid and ethylene oxide react neady quantitatively at 100°C to form tris(2-hydroxyethyl)isocyanurate [839-90-7] (THEIC) (48—52). Substitution of propylene oxide yields the hydroxypropyl analogue (48,49). At elevated temperatures (- 200° C). CA and alkylene oxides react in inert solvent to give A/-hydroxyalkyloxazohdones in approximately 70% yield (53). Alternatively, THEIC can be prepared by reaction of CA and 2-chloroethanol in aqueous caustic (52). THEIC can react further via its hydroxyl fiinctionahty to form esters, ethers, urethanes, phosphites, etc (54). Reaction of CA with epichlorohydrin in alkaline dioxane solution gives... 

The structural effect of alkyl groups such as methyl, ethyl, and -butyl on the Rp is small. Alkyl 4-methyl-phenylcarbamate can be chosen as a model compound for the hard segment of poly(ether-urethane) (PEU). This group can initiate grafting reaction with Ce(IV) ion and the grafting site was proposed at the hard segment of PEU [3,15] as shown in Scheme (1). 

Segmented Poly(ether urethane) Filins Containing Ferrocene Units in the Hard Segments... 

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. 

Stepwise addition polymerization is used in the preparation of segmented polyurethanes (compare Sect. 4.2.1), e.g., poly(ester ether) urethanes which also find application in thermoplastic elastomers. Here, both blocks are preformed separately and are linked together by reaction with isocyanates ... 

Biomer is a commercially available, medical grade segmented poly(ether urethane urea) (PEUU), which is prepared by treating an isocyanate-capped polyetherurethane with diamine (e.g. ethylenediamine) as chain extender... 

G. Chatterjee, A.A. Houde and S.A. Stern, Poly(ether methane) and Poly(ether urethane urea) Membranes with High H2S/CH4 Selectivity, J. Membr. Sci. 135, 99 (1997). 

A reactive macrocyclic ether-urethane carbodiimide (MC-CDI), which is the key intermediate for synthesizing poly(amide-urethane) and poly(amide-imide-urethane), was prepared by the sequential self-repetitive reaction. A se-... 

Yoon [83] studied by X-ray photoelectron spectroscopy the surface structure of segmented poly(ether urethane)s and poly(ether urethane urea)s with various perfluorinated chain extenders and noticed that the surface topography of such polymers depended strongly on the extent of phase separation. 

Aging-resistance. Aging-resistance specifically describes the capacity of materials to resist critical stress-induced cracking. The majority of plastics or elastomers are lacking in aging-resistance, except for biomedical-grade poly (ether urethanes) and their derivative products. 

Peng, Z.L., Wang, B., Li, S.Q., Wang, S.J. (1994) Free volume and ionic conductivity of poly(ether urethane)-LiC104 polymeric electrolyte studied by positron annihilation . J. Appl. Phys. 76(12), 1. 

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]. 

Combustible when exposed to heat or flame can react with oxidizing materials. To fight fire, use water, CO2, dry chemical. Potentially explosive reaction with concentrated nitric acid. Incompatible with acetanilide, alkalies, ferric salts, spirit nitrous ether, urethan. When heated to decomposition it emits acrid smoke and irritating fumes. 

Table II. Comparison of IPN-Modified and Unmodified Aliphatic Ether Urethanes...

Functional groups not directly attached to the thietane ring react normally. Alcohols can be converted to ethers, urethanes, ... 

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... 

These accelerated growth procedures have been used by a number of groups to synthesize dendritic poly(amides),222-224 poly(esters),225 poly(ether urethanes),226 and chiral poly(ethers).227 The orthogonality of the focal and peripheral protecting groups required for double exponential growth also enables facile modification at either the periphery or focal point. Although this approach is one of the most rapid methods yet reported for the synthesis of well-... 

Treated with sodium in ether, urethane forms a disodio derivative which reacts with two equivalents of ethyl chloroformate to form triethyl nitrogentricarboxylate. ... 

Shaded cells indicate compatibility of polymer with solvent or crosslinker PLA poly(lactic acid), PGA poly(glycolic acid) PLGA poly(lactic-co-glycolic acid), PCL poly(e-caprolactone), PEU poly(ester urethane), PEEUU poly(ester ether urethane), PVA poly(vinyl alcohol), PEO poly(ethylene oxide), HA hyaluronic acid, DMF W,W-dimethylformamide, A4 acetic acid, FA formic acid, DCM dichloromethane, HFIP hexafluoroisopropanol, THF tetrahydrofuran, GA glutaraldehyde, NMMO N-methyl-morpholine A -o, idc/water (NMMO/water)... 

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

Christenson, E.M., Patel, S., Anderson, J.M., and Hiltner, A. (2006) Enzymatic degradation of poly(ether urethane) and polycarbonate urethane) by cholesterol esterase. Biomaterials, 111 (21), 3920-3926. 

BENZENEDIOL (108-46-3) Combustible solid (flash point 261°F/127°C cc). Dust or powder forms explosive mixture with air. Violent reaction with strong oxidizers, nitric acid. Incompatible with acetanilide, alkalis, ammonia, amino compounds, antipyrine, camphor, ferric salts, lead diacetate, menthol, spirit nitrous ether, urethane. May accumulate static electrical charges, and may cause ignition of its dust. 

---