The chemistry of the official match ball of the World Cup - the 2014 FIFA World Cup - the Brazooka

We haven't forgotten the 2014 World Cup soccer games, the World Cup, which will begin this Friday with the quarter-final stage. The cover, lining and bladder of the ball achieve a physical goal of speed and strength, but none of this would be possible without the chemistry. The breakdown of the different polymers used in each of the parts of the ball

In previous articles in the series we described the The aerodynamics of the game ball of the 2014 FIFA World Cup, as reflected in the NASA wind tunnel and The physics of football. With the start of the quarter-final stage of the World Cup, we return to the subject, and this time from the chemical aspect.

A number of chemical substances are used in the production of the Brazuca, the official match ball for the 2014 World Cup. Most of these substances are polymers - very long molecules made up of many smaller molecules. A simple, everyday example is the polyethylene polymer used to make plastic bags. Different groups of polymers are used to achieve unique properties for the ball.

A football consists of three main parts: the cover (the outermost layer), the lining and the bladder (the inner). It goes without saying that all three of these parts will be designed in such a way as to provide the most preferred aerodynamic properties for the ball, however, from here we are already entering the territory of the field of physics. None of these features will be achieved without the chemistry that provides the required materials, and here we list the different types of polymers used in each of the parts of the ball.

The cover

The cover consists of six polyurethane sections (Wikipedia) that are thermally bonded together. This cover is very important to protect the ball, and it is designed to prevent it from absorbing a large amount of water and moisture - the water absorption rate of the Brazooka ball (Wikipedia) is only 0.2%. This feature makes the ball much lighter than the previous balls that were covered with a layer of leather. Some balls also have a layer of polyurethane foam under the cover layer. Polyurethanes consist of compounds called isocyanates (Wikipedia) and polyols (Wikipedia). The central parts of these molecules can be changed and adjusted, giving the different polyurethanes the different properties. Polyurethanes have a wide variety of applications, including foams in adhesives, synthetic fibers, and even skateboard wheels.

Cheaper balls use PVC [polyvinyl chloride] instead of polyurethane for the coating. In these balls the cover sections are sewn together one to the other and are not thermally fused as in the new ball. The sewing of these segments is done with the help of another type of polymers called polyesters (Wikipedia), which can be reinforced with Kevlar fibers.

the lining
Underneath the cover layer, the ball will have several layers of lining. These are designed to improve the detection capabilities and strength of the ball. In the new ball, these layers are composed of a different type of polymers called poly-amides, which in everyday life is called nylon. Polyester type polymers can also be used for this purpose. Nylon and polyesters are also common as components in the production of football shirts, as well as in the production of other clothing items. Nylon material is also used in parachutes, ropes and fishing nets, while polyesters are used in bed sheets, carpets and plastic bottles.

Ball bladder (internal)
The bladder is the part of the ball that stores the air inside. In the Brazooka ball, this part is made of butyl rubber, but it can also be made of the latex material. Each has its advantages: butyl rubber retains the air inside for longer, while latex provides better surface tension. The butyl rubber material can also be found in the valve through which the air can be introduced into the ball, where it helps to trap the air. Silicone valves can also be used.
Even within most types of chewing gum you can find food grade butyl rubber which is designed to give the gum its elasticity. Unfortunately, this substance is also responsible for the unwanted stickiness of chewing gum. This rubber is also found in the inner parts of tires.

Here we have provided you with just a glimpse into the world of polymers - every type of plastic we use on a daily basis is made up of polymers, as well as our clothing and other everyday products.

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