The Chemistry of a Football Helmet

Introduction

I recently did a project on the chemistry of a football helmet. I chose this item because football is one of my passions and I was interested in how football helmets are made. My safety and health relies on these helmets during my participation in the sport. Chemistry is a vital factor in the production of these helmets because miscalculations could lead to severe injury to the head. These helmets are composed of a polycarbonate shell, polyurethane padding, synthetic rubber, and a titanium facemask.

Composition of ...

• Polyurethane- Padding- C25H42N2O6
• Synthetic Rubber- Interior of Helmet- C4H6
• Polycarbonate- Shell- [HO+2(CH3)+C+OH+CO]+Cl2
• Titanium- Facemask- Ti
• Steel Screws and Chin-Strap Clips- 2 Fe+ 3CO2
• Plastic Clips- C2H3Cl

Main Chemicals, Compounds, Components

• Polyurethane-C25H42N2O6
• How- Polyurethane is made when 2 alcohols (polyol and isocyanate) combine in an exothermic reaction. The group formed by the reaction is called urethane linkage. It is how polyurethane is made.
• What- Polyurethane is used in the foams on the inside of the helmet. This is arguably the most important part of the helmet since it absorbs shock, ultimately protecting the player.
• When-Riddell’s revolution speed helmet, which uses polyurethane, came out in 2009.
• Where- Riddell’s headquarters are in Rosemont, Illinois.
• Why- It is used to absorb shock and protect players.
• Polycarbonate Shell- [HO+2(CH3)+C+OH+CO]+Cl2
• How- Polycarbonate is made by reacting bisphenol and carbonyl chloride. The process is known as condensation polymerization. In condensation polymerization, polymerization of one or more monomers is accompanied by the elimination of small molecules (such as water or ammonia).
• What- Polycarbonate is the shell of the helmet.
• When- 2009(cont.)
• Where- Rosemont, Illinois (cont.)
• Why- The shell of the helmet is the athlete’s first line of defense. It needs to be strong for durability, yet flexible for shock absorption.

Chemistry's Role

• Polyurethane is formed when you mix equal parts of 2 liquids, A and B. This lightweight liquid expands to 30 times its size and becomes rigid/firm in 5 minutes.
• Liquid A is a viscous(sticky), cream-colored substance containing a polyether polyol, a silicone surfactant, and a catalyst. The polyether polyol is the substance polypropylene glycol [HO(C3H6O)H]. The hydroxyl (OH) at the end of the polymer is the reactive site. The silicone surfactant is used to reduce surface tension between the 2 liquids. The catalyst is used to speed up the reaction without being physically changed itself.
• Liquid B is a viscous(sticky), dark brown liquid containing diphenylmethane diisocyanate [(C6H5)2C(NCO)2].
• Liquid A+Liquid B→ Polyurethane

[HO(C3H6O)H]+[(C6H5)2C(NCO)2] → C25H42N2O6

• When liquid A and liquid B are mixed, an exothermic polymerization reaction occurs, forming polyurethane. Polyurethane is man-made and is a new substance. Without chemists, polyurethane would not exist.
• Polycarbonate is formed when bisphenol and carbonyl chloride react through condensation polymerization. In condensation polymerization, polymerization of one or more monomers is accompanied by the elimination of small molecules (such as water or ammonia).
• Bisphenol is made when propanone and phenol are reacted together. (CH3)2C+2OH→ HO+2(CH3)+C+OH
• Carbonyl Chloride is produced from carbon monoxide and chlorine.

CO+Cl2→ COCl2

• Bisphenol+Carbonyl Chloride→ Polycarbonate

[HO+2(CH3)+C+OH] + COCl2→ [HO+2(CH3)+C+OH+CO]+Cl2

• Polycarbonate is also man-made and would not be existent without the work of chemists.

Background Research

Football helmets are made in different pieces. First, the polycarbonate shell is made through the process of condensation polymerization using bisphenol and carbonyl chloride. This shell is then cooled and molded into the shape of the helmet. This shell is designed provide hard, outer protection, while also providing shock absorption and providing resistance to thermal distortion. Next, the polyurethane padding is made by combining two substances. Substance A ( polyether polyol, a silicone surfactant, and a catalyst) and substance B (diphenylmethane diisocyanate). When these substances cool after mixing, they form a rigid foam that absorbs shock and protects its player. Both substances are made in Rosemont, Illinois, Riddell’s headquarters.

Resources

http://www.icis.com/resources/news/2009/08/24/9240644/the-history-of-chemicals-and-the-football-helmet/

History of the Football Helmet

http://en.wikipedia.org/wiki/Revolution_helmets#Rehttp://en.wikipedia.org/wiki/Revolution_helmets#Revolution_Speed_Helmetvolution_Speed_Helmet

Information on the Revolution Speed Helmet

What the Helmet Consists of

http://polyurethane.americanchemistry.com/Introduction-to-Polyurethanes

Information on Polyurethane

General Properties of Polyurethane

http://termine.com/archives/488

Information on Polycarbonate

http://en.wikipedia.org/wiki/Polyurethane

More information on Polyurethane

How Polyurethane is Made

https://www.flinnsci.com/media/620296/91056.pdf

Molecular Formula of Polyurethane

Steps of Making Polyurethane

http://www.britannica.com/EBchecked/topic/86401/butadiene-rubber

Molecular Formula of Synthetic Rubber

http://www.polymerprocessing.com/polymers/PC.html

Molecular Formula of Polycarbonate

http://www.essentialchemicalindustry.org/polymers/polyurethane.html

Process of Making Polyurethane

http://en.wikipedia.org/wiki/Riddell

Location of Riddell

http://www.essentialchemicalindustry.org/polymers/polymers-an-overview.html#condensation

How Polycarbonate is Made

Chemistry’s Role in Making Polycarbonate

http://www.chemistryexplained.com/St-Te/Steel.html

Molecular Formula of Steel Screws and Clips

http://www.britannica.com/EBchecked/topic/463684/plastic

Molecular Formula of Plastic Clips

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