Kevlar is a synthetic polymer that is made up of many small molecules called monomers. These monomers are held together by ester and amide bonds. Synthetic polymers have allowed for the greater variety of materials – fabrics, glass, wood, paper, etc.—that would have otherwise not have been made in nature. These materials and many others are being created to fit the needs of humans. Kevlar is a super fiber, an aromatic polyamide. It is a polymer made up of 1,4-benzene-dicarboxylic acid and 1,4-diaminobenzene. The aromatic rings in the polymer gives the molecule physical strength. To put in perspective, Kevlar has five times the strength than the equal weight in steel. The strength comes from the polymer’s ability to interact with other chains. The chains have hydrogen bonds and they form a sheet-like structure.
Origins of Kevlar
Stephanie Kwolek, a chemist, started working at the DuPont Company. Her research with high performance compounds ultimately led to the development and discovery of Kevlar.
In 1965, the DuPont Company anticipated a gasoline shortage, so Kwolek and her team took on the job to develop a new material for tires. The “spinneret” (the machine used to test the different strengths of materials) broke through nylon and other materials often, but Kwolek was surprised her new fiber did not break at all. Her discovery led to a new field of polymer chemistry that had not been explored. By 1971, the testing and refining of Kevlar was complete.
Uses of Kevlar
Kevlar is widely used today because it is light, easy to use,
and very protective. Soliders and law enforcement use it in bullet-resistant
vests.
Firefighters use it in their turnout gear for protection against cuts,
scrapes, or burns because Kevlar is stable at high temperatures. Because Kevlar
is so light, people going into these professions do not have to worry about
being weighed down by their equipment.
Ropes, hockey sticks, car parts, and even smartphones
have Kevlar. These everyday items are now more durable.
References:
1. Organic Chemitry Textbook pgs 770 & 1255
3. Pictures:
a. http://www.clipartbest.com/cliparts/aie/KKq/aieKKqyLT.gif
b. http://img.nauticexpo.com/images_ne/photo-g/kevlar-core-cordage-polyester-cover-sailboat-regatta-33266-223117.jpg
c. http://content.answcdn.com/main/content/img/shutterstock/h/a/hand_holding_cell_phone.jpg
d. http://armorcorr.com/images/bullet_proof_vest.jpg
e. http://www.chemheritage.org/Discover/Online-Resources/Chemistry-in-History/Themes/Petrochemistry-and-Synthetic-Polymers/Synthetic-Polymers/asset_upload_file297_61793_thumbnail.jpg
f. http://chempolymerproject.wikispaces.com/file/view/Untitled-2.jpg/34263993/Untitled-2.jpg
g. http://www-ics.u-strasbg.fr/etsp/lecture/mchem_poly/f/kevlar_form.gif
This was very informative! I've never even heard of Kevlar before today and yet its in my cellphone. Even better that a woman discovered it!!
ReplyDeleteVery informative. Definitely learned something new today! Thanks
ReplyDeleteThat is very interesting. I have never actually heard of Kevlar. After reading about it, I was curious as to why it is not used in more materials. Turns out it has bad compressive strength so it cannot be used for construction materials like steel can. Still impressive it can stop bullets though!
ReplyDeleteThanks for the post! I've heard of Kevlar but I didn't know this much.
ReplyDelete