Manufacturing polyols for food-based applications
Polyols that are used in food-related applications are commonly produced through hydrogenation of sugars or starches. This process involves the reaction of sugars or starches with hydrogen gas at high temperatures and pressures and in the presence of a catalyst, typically a metal catalyst like nickel or palladium.
During hydrogenation, the double bonds in the sugar molecules are saturated with hydrogen atoms, causing polyols to form.
After the reaction, the polyols are purified through distillation or crystallization to achieve a high-purity product.
Manufacturing polyether polyols for polyurethane foam and other applications
Polyols used in polyurethane foam and other non-food-related applications are often produced via the polymerization of alkylene oxides. In this method, either propylene oxide (PO) or ethylene oxide (EO) is reacted with a starter compound containing active hydrogen atoms, such as glycerol or dipropylene glycol.
The reaction takes place in the presence of a catalyst, usually an alkaline catalyst like potassium hydroxide, which facilitates the addition of the oxide to the starter molecule. The result is the formation of polyols with multiple hydroxyl (OH) groups. These polyols serve as the polymeric backbone for polyurethane foam production. Isocyanates, along with additional ingredients such as blowing agents and catalysts, are then mixed with the polyols to create the foam.
Finetuning polyols for performance
Adjusting the molecular weight of a polyol can change its characteristics and, as a result, change how it performs in a specific application. For example, the foam in a memory foam mattress is made from a blend of polyols with higher and lower molecular weights than a regular mattress. The molecular weight can affect resilience, or how long it takes a mattress to rebound after you press your hand into the foam.
Adjusting the carbon linkages in polyols can also change performance. For example, some polyols made with captured carbon instead of fossil-based carbon deliver better elasticity and strength in memory foam.
You can find a similar story in other applications like paints and coatings, where adjusting molecular weight and the distribution of polyols influences the viscosity, flow properties, and film thickness. Additionally, changing the chemical structure of polyols by incorporating functional groups such as carboxyl, or epoxy groups can improve adhesion, crosslinking, and chemical resistance of the coating.