Use of Polyurethane
Use of Polyurethane
The physical properties of polyurethane, as well as it is chemical composition, depend on the composition of the important reactions, especially the R1 and R2 groups. The properties of a polymer - the relative molecular mass, the number of photoactive active groups in each molecule, and the molecular structure - affect the final polymer property and, therefore, how it is used.
There is a fundamental difference between the manufacture of polyurethane and many other types of plastics. Polymers such as polyethylene and polypropylene are produced in chemical plants and sold as granules, powders, or films. The polymer is then heated, pressed, and cooled to form a product. The properties of these manufactured products depend almost entirely on the original polymer.
Polyurethane, on the other hand, is usually formed directly into the final product. Most are made in the form of large blocks of polyurethane foam, which are used for pillows or thermal insulation. Chemical reactions can also occur in molds, for example, car bumpers, computer cases, or building boards. This can happen when the liquid reactant is sprayed on the roof of the building or covered with a cloth.
Polyurethane can be hard or rubber, having a density between 10 kg m3 and 100 kg m3. Obviously, the general range of features for the designer and manufacturer is very wide, and this is reflected in the many and very different uses in which polyurethane is used.
