Adipic Acid-Ethylene Glycol Polyester Polyol

Polyols are the basic building blocks and backbone for producing polyurethane elastomers. These polyols are basically low molecular weight liquid polymers usually with reactive hydroxyl groups (-OH) at each end of the molecular chains. Typically, these polymers have a molecular weight of approximately 2000. 

The selection of the polyol is very important because the specific polyol selected has a great effect on the ultimate physical properties of the cured product in service, resulting in a major influence on the performance of the final polymer. 

Generally, the polyol will have either a polyester or a polyether backbone. The polyurethane elastomers based on an ester backbone generally have better abrasion resistance, tensile strength, tear strength, and oil resistance. On the other hand, polyurethane elastomers based on a polyether backbone generally possess better low-temperature properties, resiliency, and resistance to hydrolysis. 

In the past, fabricators would commonly mix directly a preselected polyol with an isocyanate and chain extender in what was called a one shot method. However, today, it is far more likely that the fabricator will have the supplier prereact the polyol with a designated diisocyanate to form what is called an isocyanate-terminated prepolymer. The fabricator would rather work with these isocyanate-terminated prepolymers because there should be less chance of worker exposure to free isocyanates in the product fabrication. There are significant worker safety concerns with exposure to isocyanates. 

2 Adipic Acid-Ethylene Glycol Polyester Polyol 

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The adipic acid-ethylene glycol polyester polyol represents a typical polyester polyol. This polyol is a product of the reaction of adipic acid with ethylene glycol as shown in Figure 7.4. 

Adipic Acid-Ethylene Glycol Polyester (Polyol)... 

Adipic acid-ethylene glycol polyester polyol is also used in making foams, adhesives, coatings, and so on. 

Adipic acid is directly used to synthesize adipic acid-ethylene glycol polyester (polyol) for polyurethane rubber use. 

Ethylene oxide is used to make ethylene glycol to react with adipic acid to form adipic acid-ethylene glycol polyester (polyol) for polyurethane applications. EO is used as a feedstock to synthesize ethylene carbonate, which is used to make HER for polyurethane chemistry. 

Both polyethers and polyesters may be used as polyols. For example, Du Pont use polytetrahydrofuran for Lycra whilst US Rubber originally used a polyester of molecular mass of about 2000 obtained by condensing adipic acid with a mixture of ethylene and propylene glycols. A polyether-based mixture was used for Vyrene 2 introduced in 1967. All the polyols have terminal hydroxyl groups. 

Polyesters are another important class of polyols. There are many polyester types used, so a generic structure is shown in Scheme 4.4. They are often based on adipic acid and either ethylene glycol (ethylene adipates) or 1,4-butanediol (butylene adipates). Polyesters, because of the polar carbonyl groups, contribute more to intermolecular forces, and physical properties such as tear and impact resistance are often improved by using them. They are also utilized for their solvent and acid resistance and light stability. Relatively poor hydrolytic stability is... 

Polyester polyols are an important class of urethane raw materials, with applications in elastomers, adhesives, etc. They are usually made from adipic acid and ethylene glycols (polyethylene adipate) ... 

This particular polyester polyol is dependent on the availability of adipic acid and ethylene glycol. 

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