What has become a pseudo National Holiday in the U.S., this weekend marks the 48th Super Bowl pitting the Seattle Seahawks against the Denver Broncos. I, like millions of fellow Americans and others around the world, will be glued to the television Sunday afternoon to watch the game and enjoy the company of friends. Now, you may be wondering what the Super Bowl has to do with science, and specifically Chemical Engineering. The beauty of science is that it plays a role in all aspects of life and shapes all that we know in the world. In regards to the Super Bowl, applications of Chemical Engineering can be identified in the equipment used, namely the footballs and helmets.
In the early stages of American football, the ball was made of inflated pig’s bladder, which is where the common expression “pigskin” comes from. Obviously, the material and method for constructing footballs has advanced over the last century into what is seen being using everyday Sunday. The modern football is an inflated rubber bladder enclosed in leather. The rubber bladder is made of butyl rubber which is made by polymerizing 98% polyisobutylene and 2% isoprene. This reaction is a cationic addition polymerization reaction, meaning the cation (+) moves its charge to a monomer making it more reactive. Polyisobutylene can be stretched to extreme distances and than revert back to its beginning shape. Butyl rubber is impermeable to air making it ideal for the middle of a football.
There are two types of leather used to construct footballs. Real leather balls are the highest grade and more expensive, they also are more resistant to water and have a better grip. Traditional leather is formed by taking a raw hide of cow and tanning it. Chromium is commonly used in the tanning process. The leather is repeatedly worked and submerged in tanning oil. The enzymes in tanning oil thins the leather, while maintaining its flexibility and water resistance.
Composite leather is used as a substitute to traditional leather. It is made by combining a binding material with leather components and a few softeners and cushioning agents. Latex is a common cushioning agent and polymeric foam acts as a binding material. Basically, the composite leather skin is made of amino acids that combine into a collagen. Scientists are currently exploring making a football that “feels” more comfortable coming right out of the box. Also, with the frigid weather experienced across the U.S. this year, scientists are looking for a composite leather that is unaffected by the cold. Traditional leather drastically hardens in cold conditions, making it tough to play with.
I also took a look at the science behind football helmets. Helmets have evolved from leather caps to modern helmets with lightweight but incredibly strong plastic. The plastic used in helmets must have malleable qualities so it gives slightly when hit and doesn’t shatter with the stress. The plastic, however, must be strong enough to withstand immense contact. There has been much coverage about concussions over the past few years, so scientists are committed to inventing helmets that protect against concussions. Check out some of the links and YouTube clip of how helmets are made.