Urethans ethylene derivatives

For the most part, additives control the appHcation or theological properties of a paint. These additives include materials for latex paints such as hydroxyethylceUulose, hydrophobicaHy modified alkah-soluble emulsions, and hydrophobicaHy modified ethylene oxide urethanes. Solvent-based alkyd paints typically use castor oil derivatives and attapulgite and bentonite clays. The volume soHds of a paint is an equally important physical property affecting the apphcation and theological properties. Without adequate volume soHds, the desired appHcation and theological properties may be impossible to achieve, no matter how much or many additives are incorporated into the paint. 

Ethylene derivatives from urethans Rearrangement of terpenoids... 

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... 

Other Derivatives. Ethylene carbonate, made from the reaction of ethylene oxide and carbon dioxide, is used as a solvent. Acrylonitrile (qv) can be made from ethylene oxide via ethylene cyanohydrin however, this route has been entirely supplanted by more economic processes. Urethane intermediates can be produced using both ethylene oxide and propylene oxide in their stmctures (281) (see Urethane polymers). 

Figure 25.3 b) shows a generic polyester-based polyurethane. The most common polyester repeat units are derived from the polycondensation of adipic acid and a diol, such as ethylene glycol, which results in the structure shown in Fig, 25.4. The average molecular weight of the polyester sequences between urethane links commonly ranges between 400 and 6,000 g/mol. 

For those familiar with polymer chemistry, polyurethane may be a confusing term. Unlike polyethylene, the polymerization product of ethylene, a polyurethane is not the result of the polymerization of urethane. To add to the confusion, a urethane is a specific chemical bond that comprises a very small percentage of the bonds of a polyurethane. Since we are interested in chemical and physical effects, polyether or polyester is a more descriptive term for the most common bond in a polyurethane. Despite this complication, it is instructive to begin by talking about the methane bond from which the polyurethane name is derived. The general structure or bond that forms the basis of this chemistry is the urethane linkage shown in Figure 2.1. 

The solubility data in Table I may be used to test the log P correlations in poly(ethylene-co-vinyl acetate) and polyether-urethanes. The correlations in Equations 19 and 20 are derived by combining this data with the reported (20) water solubilities and octanol-water partition coefficients of the steroids (22-24). 

Polyesters derived from e-caprolactone and ethylene glycol and triols, such as trimethylolpropane, have been employed for the preparation of different types of urethane coatings, including nonyellowing systems (88. 89). These types of polyesters exhibit improved hydrolytic stability and low-temperature properties as compared to adipate polyester based urethanes. 

Dimethylamino ethanol (DMAE) n. A colorless liquid derived from ethylene oxide and dimethylamine, a catalyst for urethane foams. It has little odor and toxicity, and resists staining. 

Nathan A, Bolikal D, Vyavahare N, Zalipsky S, Kohn J (1992) Hydrogels based on water-soluble poly(ether urethanes) derived fiom L-lysine and poly(ethylene glycol). Macromolecnles 25 4476-4484... 

---