Definition of polyurethanes:

Polyurethanes are a type of polymer, formed by reacting diisocyanates and polyols in the presence of a catalyst or ultraviolet light. They are used in a range of industrial and consumer applications, such as foams, fibers, and coatings.

What are polyurethanes?

Polyurethanes are a type of polymer. They're formed by the chemical reaction between a polyol (an alcohol with more than two reactive hydroxyl groups per molecule) and a diisocyanate or polymeric isocyanate. This reaction requires the presence of suitable catalysts and additives to take place.

One popular use of polyurethane is as flexible foam. This is found in many home furnishings like chairs, sofas, bedding, and carpet underlay. Polyurethanes can also be found in adhesives, elastomers, rigid and flexible foams, coatings, car parts, shoe soles, upholstery material, and textiles such as Spandex.

As coatings, they make a substrate more durable, increase its resistance, and offer protection against water damage and scratches.

Why are polyurethanes important?

The main reason is their versatility. Polyurethanes can be molded into different shapes and adapted to suit a huge range of industrial and consumer applications. They are also long-lasting: the polyurethane used in automotive seats, for instance, lasts for the car's entire lifetime.

The low density of polyurethanes also makes them useful for designing lighter objects. Vehicles with polyurethane components have significantly better fuel economy than those using heavier alternatives.

What are the challenges related to polyurethanes?

While polyurethanes have many useful applications, they have certain limitations too. They generally have poor weatherability, are attacked by most solvents, and are highly flammable. There is also concern about the use of toxic isocyanates in certain types of polyurethane.

In addition, the polyurethane production process continues to be over-reliant on fossil-based feedstocks. This means there is scope to reduce the environmental impact of this material.

What is the future of polyurethanes?

Responsibly produced polyurethanes will become more widespread in the coming years, thanks to innovations such as Stahl’s NuVera® range. These polyurethanes are made from renewable feedstocks such as plant biomass and captured carbon from industrial processes. This helps reduce our dependence on fossil-based feedstocks.

Stahl is also an integral part of the Bio NIPU project. This interregional research consortium aims to pave the way toward 100% bio-based and non-toxic polyurethanes. Bio-based polyurethanes perform just as well as their fossil-based counterparts while carrying a reduced carbon footprint.

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