Ethylene-capped polyether polyols

A High Molecular Weight, Ethylene Oxide Capped Polyether Polyol with a Hydroxyl Number of 34. 

All the oligo-polyols are used to build the polyurethane high MW structure in a reactive process, as a consequence of the oligo-polyols terminal hydroxyl group reaction with polyisocyanates. The reactivity of oligo-polyols in polyurethane fabrication is a very important practical characteristic. Reactivity is a measure of the reaction rate of an oligo-polyol with an isocyanate in order to make the final polyurethane polymer. One practical method is the measurement of viscosity, in time, by Brookfield Viscosity Test (BVT), especially used to determine the reactivity of ethylene oxide capped polyether polyols. Figure 3.12 shows the effect of the primary hydroxyl content upon the reactivity of ethylene-oxide capped polyether triols of MW of 5,000 daltons. 

Other polyamine derivatives are used to break the oil/water emulsions produced at times by petroleum wells. Materials such as polyether polyols prepared by reaction of EDA with propylene and ethylene oxides (309) the products derived from various ethyleneamines reacting with isocyanate-capped polyols and quaternized with dimethyl sulfate (310) and mixtures of PEHA with oxyalkylated alkylphenol—formaldehyde resins (311) have been used. 

FLEXIBLE BACKBONE 1. Polyether polyols made with propylene oxide and "capped" with ethylene oxide. 

Graft polyols made from grafting polyacrylonitrile onto the basic polyether (also ethylene oxide -"capped"). 

The synthesis of the poly(alkylene oxide)s for elastomers is contained in Chapter 4, Sections III. A, IV, and V. For polyurethane elastomers based on propylene oxide, the polyethers prepared are secondary hydroxyl-terminated polyethers. The secondary hydroxyl group is slower to react with isocyanate than is a primary hydroxyl (Table 3) (20). Therefore, poly(propylene oxide) diols and higher functionality polyols are often capped with ethylene oxide (see Chapter 4, Sections IV and V) to obtain the more reactive terminal, primary hydroxyl groups. 

---