Chances are, if you look round your present environment, you’ll see something that’s made of polyurethane, also known as PU. Used to create everything from building insulation through to furniture upholstery, mattresses, sportswear, shoe soles and many other items, it’s become an essential material in the 21st Century home, office and vehicle.
One of the reasons why PU is such a popular option is its versatility. Unlike other materials, which have a static set of parameters, PU can be created to fulfil a wide range of specifications. Read on to discover what PU is and how its unique construction enables it to adapt to an intriguing selection of different applications.
Without knowing something of polyeurethane’s unique composition, it’s hard to work out how it’s able to exist in so many different forms.
Tough enough to make bowling balls from, yet also soft enough to be comfortable to sit on, it’s clear that there’s something very special about PU’s make-up. PU may act like a plastic, but it’s not – in the same way that PU may act like rubber or metal, but is none of these things.
Polyeurethane is a polymer that’s made of different monomers. Plastic is a polymer, but one that’s only made of one monomer.
This means that each type of plastic (PVC, PETE, PP, for example) has a fairly static set of properties. Because PU is a copolymer (a polymer that’s made up of more than one monomer), it can be adjusted to possess a wide range of properties, by altering the monomer proportions and type. It is this that causes PU to imitate other materials such as plastic or rubber, but the reality is that PU is a unique material in its own right.
What are the benefits of PU?
It’s clear that the popularity of PU isn’t just down to its versatility, although this is clearly an important consideration. Other advantages of opting for a PU product are:
- PU is extremely tough: highly durable and resistant to corrosion, it’s also resistant to UV light, salt and weathering.
- The material is an excellent insulator, which is why it’s commonly used on roofing projects.
- PU can often be recycled. Because it’s made from petroleum-based ingredients, if it can’t be recycled it can be burned, providing energy for heating and other purposes.
- It’s available in a wide range of colours.The material isn’t brittle, enabling it to be shaped and moulded with ease.This material is simple to shape, enabling intricately-designed PU products to be created.
What properties does PU have?
Depending on the proportions and types of monomer involved in the creation of PU, the compound can have any or all of the following properties:
- Hard or soft – PU may be manufactured so that it is tough enough to make furniture and parts for cars, or soft enough to use in bedding or for a coating.
- Flexible – PU can be formulated so that it retains a soft, flexible character (for example the PU used in upholstery), or created so that it is tough and hard-wearing.
- PU can be created in almost any colour.
- PU can be moulded into almost any shape.
These properties mean the material can be used in many different ways, whilst still retaining the intrinsic properties which characterise PU.
Although polyurethane does share many of the characteristics of plastic, it’s not, technically, a plastic. Neither is it a rubber. Rather, it is a complex and variable mix of petrochemicals which can be formulated to deliver a wide range of different results.
Developed in the 1930s, applications for PU have gradually expanded as its possibilities have been more widely explored. With possibilities arising not just to vary the internal chemistry of the material, but also to alter the way in which it was processed (for example by “blowing” to make the PU less dense (this increases its flexibility, adding to the ways that it can be used), PU has rapidly become one of the most widely used materials on the planet.
The future for PU continues to look bright: there is considerable research taking place into the use of greener, plant-based monomers, as well as looking at ways to make manufacture more environmentally friendly. Given its amazing adaptability, it’s likely that PU will continue to play a major role in a wide variety of goods for many years to come.