POLYOLS

In organic chemistry, a polyol is an organic compound containing multiple hydroxyl groups (−OH). They are versatile compounds that serve a multitude of purposes. The two primary types of polyols are polyether polyols and polyester polyols. There are also polymer polyols which are essentially modified variants of the first two types of polyols. Polyols of varying molecular weight, functionality, viscosity and reactivity can be produced. They are liquid under room temperature, not classified for physical hazards. They are not flammable, but they will burn.

PROPERTIES​

Hydroxyl Value ( VOH ) - The number of reactive hydroxyl groups (OH) on the polyol directly impacts the quantity of urethane linkages, which greatly influences the physical properties of the final PU product.​
 Acid Value ( VA ) - should be as low as possible, otherwise it will bring adverse effects on processing and product performance, so it is particularly important to determine the acid value.
Water Content - In addition to density and basic mechanical properties, the water content affects the gelation time and thermal conductivity of polyurethane.​

POLYETHER POLYOLS

POLYETHER POLYOLS are polymerized products, made by reacting organic oxide and glycol. Main organic oxide utilized are ethylene oxide, propylene oxide. Main glycols utilized are ethylene glycol, propylene glycol, glycerine, sorbitol, sucrose, water and amines. These polyols are known for their secondary hydroxyl groups, which make them highly reactive.

One of the defining features of polyether polyols is their high molecular weight. This gives them the ability to produce foam with excellent cushioning properties. Additionally, they are relatively easy to handle and store, making them a popular choice for many manufacturers.

They are commonly used in the production of flexible foam, often found in furniture and bedding, as well as in rigid foam, used for insulation. Polyether polyols account for about 90% of the polymeric polyols used industrially; the balance consists of polyester polyols.

POLYESTER POLYOLS

POLYESTER POLYOLS are produced through the reaction of terephthalic acid with various alcohols.

Unlike polyether polyols, polyester polyols have primary hydroxyl groups, which make them less reactive but more resistant to hydrolysis.

Polyester polyols offer a wide range of properties, including better adhesion and higher resistance to solvents and chemicals compared to their polyether counterparts.

Their wide range of properties makes them ideal for coatings, adhesives, and high-performance elastomers. Polyester polyols can also be used to produce rigid foam.

POLYMERIC POLYOLS

POLYMERIC POLYOLS are essentially polyether or polyester polyols that have been modified with styrene acrylonitrile (SAN) or other polymers to improve their functionality. In the classification below, the percentage represents the content of SAN.

POLYOLS FROM VEGETABLE OILS

Although vegetable oils are not naturally present as polymers, they are precursors for monomer chains that can be used to synthesize various polymers including polyurethane, polyester, polyether and polyolefin.​
Used for making rigid foam.​

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