Polyurethane, or PU or PUR, is an organic polymer with many organic units connected by urethane molecules. Most polyurethanes fall under the category of thermosetting polymers since they do not melt when heated. It’s worth noting that some varieties of polyurethanes are thermoplastic, meaning they can be heated and reshaped.
Polyols and di- or tri-isocyanates are chemically combined in traditional polyurethane preparation procedures. Because polyurethanes have two types of monomers that are polymerised sequentially, they can be considered alternating copolymers. The monomers utilised to create polyurethanes, such as polyols and isocyanates, typically have at least two functional groups per molecule.
Properties of Polyurethane
How polyurethanes are made has a significant impact on their characteristics. For instance, the result will be supple and elastic if the polyol chain, a raw element utilised to produce polyurethane, is lengthy and malleable. The opposite is true for polyurethane: a strict and rigid result will result from excessively high cross-linking levels. Highly molecular weights are ascribed to the polymer by its cross-linked structure, which usually comprises three-dimensional networks. This structure also explains why the polymer is thermosetting since polyurethane does not typically undergo thermal softening or melting.
Why Polyurethanes Are Beneficial
A highly valued property of polyurethanes is their capacity to be transformed into foams. To do this, a gas, often carbon dioxide, is produced during urethane polymerisation. One more perk of polyurethane (ยูรีเทน, which is the term in Thai) is that it doesn’t require blowing agents to make microcellular foams with a high density.
Uses for Polyurethane
Following is a list of some significant uses for polyurethane.
- Producing foams is the principal use of polyurethane. Fabrics for upholstery, home furnishings, and refrigerator sheets incorporate these foams.
- Certain clothing items also incorporate polyurethane.
- Door frames and columns can also benefit from polyurethane mouldings. Headers and balusters for windows often make use of such mouldings.
- Mattresses and other sleeping products often use pliable, low-density polyurethane foams. Car seats and upholstery also make use of them.
- Partially elastic bands and straps are also made from flexible polyurethane.
- Shoe manufacturers rely heavily on polyurethane’s low-density elastomers.
- The production of sponges in the kitchen and bathrooms is another prominent use of polyurethane. It finds additional application in the couch and seat cushions.
Polyurethane sealants provide more secure seals than their conventional alternatives, while polyurethane adhesives have excellent bonding properties, mainly when used immediately after production. Elastomers made of polyurethane can be moulded into any shape that is needed. They are more resistant to environmental factors, lighter than metal, and have better stress recovery capabilities.