Saturday, September 5, 2015

Kevlar


The Genius of Stephanie Kwolek



Most of you know, by now, that I volunteer in the Children’s Room of the Santa Fe  Library.  I am amazed every week by the number of volumes we have for children of all ages and the wide variety of topics these books cover.  Last week I happened upon a book, quite by accident.  Here was the story of the DuPont chemist who discovered the formula for synthesizing the fiber we know as Kevlar.




The Woman Who Invented The Thread That Stops Bullets -
The Genius of Stephanie Kwolek, Edwin Brit Wyckoff, 
Enslow Publishers, Inc., Brooklyn Heights, NJ, 2014



Born on July 31, 1923 in Kensington, Pennsylvania, Stephanie Kwolek had intended to become a physician.  She majored in chemistry at the Carnegie Institute of Technology, graduating in 1946.  Working at DuPont was meant to be a temporary stop on her way to a medical career.  She would remain at DuPont as a chemist for 40 years.

In 1964 she led a group of chemists searching for a lightweight, super strong fiber for the manufacture of automobile tires.  Lighter weight tires could reduce gasoline consumption and there was anticipation of a shortage in the future. More than 100,000 chains of chemical polymers were produced but none had the desired strength.

Kevlar_chemical_structure_H-bonds.png (2481×1243)


Poly-paraphenylene terephthalamide solution was cloudy and thinner than other tested solutions.  Beneath the microscope the chemical chains were straight and in alignment after spinning. Testing proved the fibers to be five times stronger than steel.


In 1966 Kwolek and Paul Morgan were granted patents for the fiber, It would take five more years of research for DuPont to produce a fabric that could stop bullets.  More than 200 products are made from these super strong fibers.














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