What is Polyol? What are the Types of Polyol?

What is Polyol?

Polyols are reactive raw materials containing at least 2 functional groups that react with isocyanate (NCO) groups through these groups to form polyurethane structures. Polyols are classified into various groups depending on their fields of application. Polyols are divided into two main groups: hydroxyl-terminated and amino-terminated. The properties of polyurethane products are heavily influenced by the polyols contained in them. Many chemical, physical and mechanical properties of polyurethane products are directly linked to the chemical structures of the polyols used in their formulations. The characterization of polyols used in polyurethane preparation can be performed by various methods. Polyol characterization is performed considering hydroxyl numbers, functionality, molecular weight and distribution, equivalent weight, water content, reactivity, viscosity, density, color and acid value. When usage rates in polyurethane systems are considered, polyether polyols and polyester polyols are prominently featured. Additionally, amine-terminated polyether polyols and, to a lesser extent, polycarbonate polyols are also utilized.

What are the applications of polyols?

Polyurethane structures are formed through the reaction between at least two hydroxyl functional groups on polyol structures and isocyanate groups. Polyurethanes are used in many industrial sectors, primarily including the footwear sector, construction sector, furniture sector, automotive sector, and heating and cooling sector. Polyols are the most important reaction partners for isocyanates. Polyol compounds are characterized by their hydroxyl numbers (OH number, mgKOH/g). As the molecular weight of polyols increases, a decrease in hydroxyl numbers is observed. Polyols are mainly of two types: polyethers and polyesters, and polyether polyols account for 80-90% of polyols used today.

What are the types of polyol?

Polyol types include polyester polyols and polyether polyols. Polyester polyols are produced through condensation reactions of dicarboxylic acids and glycols. Polyester polyols are produced through polyesterification of glycols and diacids or their derivatives. Polyether polyols are polymeric structures in chain or network form polymerized such that ether bonds are formed between monomers. Polyether polyols are hydroxyl-functional oligomers used in high proportions in polyurethane production.   Source