Chemistry in sport including stadiums

Welcome back to the course and our fourth and final week of study, which explores chemistry in sport!

Modern construction materials have transformed the design and performance of sports venues, whether it be a stadium, a velodrome or an aquatics centre. Venues can be built more quickly, stand the test of time better, and have lower energy usage. For example, the setting time of concrete can be formulated with additives – it can be set more quickly to reduce the building time, or more slowly if it needs to stay liquid for longer to allow it to be pumped further. Admixtures are specially formulated products that are added in small amounts to concrete, mortar or grout during the mixing process to change the concrete properties in the plastic and/or hardened state. These admixtures were used, for example, to speed up the construction of the Beijing olympic village, tennis centre and aquatics centre.

Chemistry also provides the paints and coatings that protect surfaces from the weather and other damage, and provide a decorative finish. Many modern coatings are ‘greener’ than traditional paints, and can protect just as well – if not better. Traditional paints are derived from fossil-fuels and release large amounts of volatile organic compounds (VOCs), as the paint dries and cures, which has environmental impacts. For example, for Bayer Leverkusen’s football stadium in Germany, poly(aspartic acid) coatings were used to protect the metal girders from corrosion. The coatings dry more quickly and thicker layers can be applied, so fewer coats are needed, and as there is less solvent to be evaporated, they are more environmentally friendly.

Poly(aspartic acid): an amino acid polymer

Poly(aspartic acid) (or PASA) is a large molecule, called a polymer, made up of repeating aspartic acid subunits (called monomers). The aspartic acid monomers are linked together by heating – they react to form amide bonds on loss of water. First, loss of water forms a five-membered ring called a succinimide, and multiple dehydration reactions form a polysuccinimide. This polymer is then treated with aqueous sodium hydroxide which attacks either C=O bond of the imides in a series of nucleophilic acyl substitution reactions – the term α unit or β unit is used according to which C=O bond of the imide is attacked.

This is just one of the more complicated ways of linking together subunits to form a range of useful polymers, which we will explore in subsequent sections. First, we will introduce polymers and why they are important in sports, including use in protective equipment where strong, tough materials are required – ‘hard’ chemistry in action!

Take a look at this undergraduate video, made by Hannah as part of our first year undergraduate macromolecules course, about golf balls.

For a beginning-of-week teaser, see if you can identify the 8 pieces of protective sports equipment in the collage in the downloads section below and post your answers.