polyolstructuur

Polyolstructuur refers to the arrangement of polyols, molecules bearing multiple hydroxyl (-OH) groups. It includes the number of hydroxyl groups (the functionality), the backbone and linkages hosting these groups (such as aliphatic, ether, ester, or carbonate), and the overall architecture (linear, branched, cyclic, or crosslinked). The structure of a polyol affects reactivity, viscosity, and solubility, and thus the performance of products that use polyols, notably polyurethanes, coatings, and cosmetics.

Polyols are categorized by backbone chemistry. Polyether polyols, produced by polymerizing ethylene oxide and propylene oxide on a starter molecule, yield flexible chains. Polyester polyols form from diacid–diol condensations and typically offer good chemical resistance. Polycarbonate polyols contain carbonate linkages. Natural polyols such as glycerol and sorbitol are also used in various applications. Functionality commonly ranges from two to several hydroxyl groups per molecule.

Key structural descriptors include the number of hydroxyl groups (functionality), molecular weight, and the distribution of primary versus secondary hydroxyls. Linear versus branched backbones and the degree of crosslinking influence viscosity and the balance between rigid and flexible segments in polymers. The arrangement of OH groups along the chain affects reactivity with diisocyanates and curing behavior in polyurethane formulations.

In polyurethane chemistry, the polyol structure controls crosslink density, flexibility, and thermal properties. Higher functionality and rigid backbones tend to increase stiffness and glass transition temperature, while flexible backbones and lower functionality favor elasticity. The hydroxyl value (OHV or hydroxyl number) is a common measure of reactivity and is used to select polyols for a given formulation.