PU- Polyurethane
Properties of Polyurethane
The properties of polyurethanes are highly dependent on the manner in which they are produced. For example, if the polyol chain (which is used as a raw material for the preparation of the polyurethane) is long and flexible, the final product will be soft and elastic. On the other hand, if the extent of cross-linking is very high, the final polyurethane product will be tough and rigid. The cross-linked structure of polyurethanes generally consists of three-dimensional networks which attribute very high molecular weights to the polymer. This structure also accounts for the thermosetting nature of the polymer, since polyurethane typically does not soften or melt when exposed to heat.
Advantages of Polyurethanes
Polyurethanes have the ability to be made into foams (which is one of their most desirable properties). This is done by facilitating the production of a gas (usually carbon dioxide) during the urethane polymerization process. Another advantage of polyurethane is that high-density microcellular foams of the polymer can be produced without any blowing agents.
Applications of Polyurethane
Some important applications of polyurethane are listed below.
The primary application of polyurethane is in the production of foams. These foams are used in a variety of materials such as upholstery fabrics, domestic furniture, and refrigerator sheets.
Polyurethane is also used in some garments.
Polyurethane mouldings are also used in columns and door frames. In fact, it is not uncommon for such mouldings to be employed in window headers and balusters.
The low-density foams of polyurethane which exhibit flexibility are widely used in mattresses and other forms of bedding. They are also used in automobile seats and upholstery.
Flexible polyurethane is also used in the manufacture of partially elastic straps and bands.
The low-density elastomers of polyurethane are widely used in the footwear industry.
Another notable application of polyurethane is in the manufacture of bathroom and kitchen sponges. It is also used in seat cushions and couches.
