Plastics are gaining speed

The Summer Olympic and Paralympic Games involve more than 100 different disciplines and almost 15,000 athletes competing in over 400 events. These figures perfectly illustrate the importance of the event.

Almost all of these athletes owe a great deal to plastics, whether their equipment is made of a single polymer or several, as in the case of composite materials. There are many reasons for this and we have frequently mentioned them in Plastics the Mag (liens en fin d’article).

Competition racing chairs are made of carbon fibre and epoxy resin and weigh less than 10kg. Their shape allows them to get off to a flying start.

Why are they in such high demand? These materials’ intrinsic properties allow manufacturers to make just about anything the athletes might want; a lightweight, flexible and virtually unbreakable high jump pole for reaching the greatest heights, comfortable clothing that does not hinder movement, shoes that absorb shocks and whose elasticity makes it possible to gain those few thousandths of a second that break records...

 Not forgetting the balls, all of which are made of plastic, the innumerable protections, the prostheses for amputee athletes or the wheelchairs that are as lightweight as they are manoeuvrable, allowing lightning-fast accelerations and turning on the spot. And the list goes on!

Successful try-outs for polymers

In sports, as in many other fields, polymers are at the origin of many improvements. Although sportsmen and women now have training programmes that turn them into winning machines, the equipment they use can make the difference when it comes to gaining a few hundredths of a second or a few centimetres. For example, in the last twenty years, shoes have seen their weight reduced by 50% and now weigh less than 100g. That's a lot of grams less to carry around when you're aiming for performance in long jumping, for example. Not to mention the shoes worn by basketball players, whose air cushions and polymer foams accelerate the rebound after a jump.

As for footballers and even runners, their soles are most often made of Pebax©, a polymer developed by the French company Arkema. Although its formula is kept secret, it is known that it is a combination of a polyether, which is a flexible polymer, and a polyamide, which is a rigid polymer. Since its first appearance, it has completely replaced the thermoplastic polyurethanes used until then. Pebax© is both lighter (by about 20%) and more bouncing.

Soles amplify the rebound effect, enough to gain a few thousandths of a second.

It also allows the shoe to remain firmly in place during sudden changes in direction. According to its manufacturers, this sole is able to bend a million times without losing its properties, even in extreme weather conditions!

Plastics at the crest of the wave

The Olympic Games, even in times of Covid, are always an unparalleled spectacle full of surprises. This is especially true for the new sports that are welcomed at each Olympiad. These are oftentimes original and novel sports likely to capture the attention of a younger audience in search of extreme sensations. For example, disciplines such as surfing, sport climbing, karate, baseball (and softball, its spin-off) and skateboarding will be featured in Tokyo.

Polymers are very easy to mould and can be used to design surfboards adapted to each type of wave.

In surfing as in skateboarding, the equipment is of great importance if you want to reach the podium. It is up to the athletes to make the right choices. Although the uninitiated may believe that a surfboard is just a simple board used to do tricks on the waves, in reality it is a much more technical and complex object. A surfboard is first and foremost a more or less concave shape designed to both pivot easily and glide over the waves. There is a specific type of surfboard for each type of wave. It’s a solid bet that the surfers present at the Games will be bringing along a whole range of boards to cope with all types of conditions. Although traditionally made of wood, modern surfboards are now made of various polymers, the only materials capable of varying degrees of rigidity depending on the level of performance required. However, this is not the only reason for switching to a new material. Plastics are in fact the champions of moulding and can be given almost any shape. Today's competition surfboards are now made of plastics-based composites such as water-repellent polyethylene, or even carbon fibre and epoxy resin. As for the fins, they are most often composed of a fibre and an epoxy resin. 

Polymers keep things rolling

For skateboarding, the problem is quite different since the choice of a board depends on the type of event. To simplify matters, let's say there are two main events: street (event which consists of doing tricks on elements found in the city such as stairs for example) and ramp (event on a series of ramps which are approached with momentum to do jumps, spins, etc.).

Competition skateboards are usually made of wood and the trucks, the parts attached to the board on which the wheels are mounted, are made of metal. The wheels are all made of plastic. Wheels are made up of two parts: the core made of a fairly hard and strong polymer such as polycarbonate, which is designed to hold the ball bearing, and the tread, the part of the wheel in contact with the ground, is made of polyurethane, a fairly soft and smooth material that allows good speed. This is where things get particularly interesting: wheel manufacturers are constantly testing new grades of polymers and especially new additives to make the wheels harder or softer and less sensitive to abrasion depending on what is expected of them. For instance, skateboard wheels "go through hell" during powerslides, those tricks that consist in turning the board sideways and sliding on the four wheels, perpendicular to their rolling direction.

The skaters present at the Olympics will have to choose wisely when selecting their wheels for each event. There is an incredible variety of wheels suited to many different conditions.

As skaters know, there is no such thing as a universal wheel. If the wheels are too soft, they will have more grip but will not allow high speeds. Much like the surfers, the skaters will have to travel to Tokyo with an impressive number of wheels in order to adapt to the specificities of the slopes and the climate, which affects grip. Underneath its fun and relaxed appearance, skateboarding is above all a mechanical sport which is very dependent on the quality of the equipment and therefore the materials that make it up.

Safety first with plastics

Sport climbing will be one of the many new disciplines at this year's Olympics. Here too, equipment is important, as Angy Eiter, holder of several climbing world records, recently explained to us (https://plastics-themag.com/Modern-equipment-is-much-more-comfortable-and-safer).

Last but not least on our list of new sports we will be seeing in Tokyo is Karate. It is somewhat of an exception in that the equipment does not play a role in the race for medals. However, a good tatami can prevent many injuries. For a long time now, the tatamis used for martial arts have been made of polyethylene or polyurethane foam covered with PVC. No better shock absorbing material has yet been found for cushioning falls. It should be noted that these materials are also used in gymnastics, for the same reasons. Some are even enriched with silver ions to prevent the proliferation of bacteria, viruses and fungi. They also have the added benefit of absorbing bad odours.

Polymers rule the track

The Olympic stadium and the athletics track are strong emblems of each Olympiad. While each sport has its own fans, athletics remains the flagship discipline, the one that can attract nearly a billion television viewers worldwide, as was the case for the 100m final in London in 2012. Breaking an Olympic record means glory for the athlete... but also for the city hosting the Games. Mexico City will always be remembered as the city that allowed Bob Beamon to break the Olympic long jump record*. 53 years later, this record has still not been broken! 
This is a good reason to pay special attention to the track and do everything possible to make it as fast as possible, hoping that the athletes will have the legs to go for the record.

The designer of the track is duly selected from among the companies in the world capable of creating it. For Tokyo, the Italian company Mondo was chosen. The exact composition of the track is highly confidential. All we know is that it is a mixture of different polymers, including rubber for its elasticity and rebound effect, SBR (a copolymer of butadiene and styrene) for its mechanical strength and EPDM (ethylene propylene diene monomer) for its very good weather resistance.

The composition of the athletics track is one of the most closely-guarded secrets of the Olympic Games. All we know is that some polymers are involved.

 *It is true that the Olympic record of 8.90m remains unbroken. However, the world long jump record has been held since 1991 by the American Mike Powell (8.95m) but it is not an Olympic record because it was broken at the World Championships.

Links:
Sporting records: polymers collect trophies
Golden Ball for plastics
Tour de France: plastics on the right track!
Plastics on the starting blocks