, like all plastics, are polymers made by reacting diisocyanates (MDI and/or TDI) with a range of polyols. Depending on the desired end product, chemical formulations may contain other ingredients such as catalysts, blowing agents and possibly flame retardants. These various combinations allow the manufacture of a range of product types including:
rigid and flexible foams
rigid and flexible integral skin foams
The density of the product is determined by the amount of blowing agent used, and the flexibility or rigidity by the type of polyols and diisocyanates involved.
Different forms of polyurethane are often combined with other materials to manufacture a variety of end products, for example:
insulated building panels
mattresses and upholstered furniture
domestic refrigerators and freezers
composite wood panels
Learn more about polyurethanes and their applications.
Structure of polyurethanes
Polyurethanes are polymers. Polymers are best thought of as chains of three-dimensional structures made up of long, repeating smaller units called monomers. These monomers contain carbon, hydrogen, oxygen and nitrogen. To form the chains, the smaller links are "polymerised" or hooked together.
There are thousands of naturally occurring and man-made polymers. The first man-made polymer to be produced was Bakelite in 1909. Rayon, the first man-made fibre polymer, was developed in 1911. Other well known polymers include nylon, silicon, polyethylene, polypropylene and polystyrene.