Imagine
this. It is 1964. You are a chemist working in a research laboratory of
a major company. Your boss has asked you to find new synthetic polymers.
You spend some of your time experimenting with the polymers you and your
coworkers have already made, while other times you are busy combining, heating,
stirring, and spinning different substances to see what you can create.
Because you studied chemistry in college, and because you have worked in
this laboratory for a few years, you know your stuff and have fun working
with the other chemists.
One day, you combine some substances and heat up your mixture carefully,
just as you do every day. But this day, something strange happens. The
mixture is cloudy instead of clear. When you stir it, it doesn't look
the way you expect. Something clicks in your head, and you rush to find
the person in charge of testing new polymers. He isn't at all sure he
wants to test this strange glop, but, after talking to him for a long
time, you convince him. You're just sure there is something unusual
about the substance in your test tube. You are right. When they hear the
results of the tests, your colleagues run into your lab, excited and
amazed. You have just invented a brand new polymer that weighs very
little but is strong and stiff beyond anyone's imagination. A few years
later, your discovery is used to make bullet-resistant vests and
helmets. Your name and picture are in advertisements and billboards as
the woman who saved thousands of lives.
The Making of a Chemist
In March 1996, Stephanie Kwolek shared her experiences with middle
school students in one of the Lemelson Center's Innovative Lives
programs."I did not start out to be a chemist. As a child, I thought
that I might be a fashion designer. I spent an awful lot of time drawing
various types of clothes and sewing," remembers Kwolek, the famous
chemist in the previous story. Kwolek loved being outside as much as
inside. She spent hours exploring the woods and creeks around her home
with her brothers. Her father, who died when she was young, encouraged
her to learn about nature by this first-hand experience. In school,
Kwolek enjoyed her science and math classes. Her teachers encouraged
her, helping her be a good student and talking to her about careers in
science and chemistry. All of this was news to Kwolek, who had never
heard of chemists or professional scientists. In high school, she
decided she wanted to have a career in medicine, which meant going to
college and then to medical school. As she explains, "I was always
interested in science and mathematics. It was only natural I would go
into some form of science."
Kwolek went to a women's college that was part of a much larger,
all-men's university, as was common in those days (Today, the two
colleges are both part of the co-ed Carnegie Mellon University.) She
liked meeting professors and fellow students who were women interested
in science; she also took some courses in the men's college. After
majoring in chemistry, Kwolek was still absolutely convinced she wanted
to go to medical school. But, she had to make money in order to fulfill
her dream. So, she interviewed for jobs at several research companies,
including the DuPont company. The interviewer from DuPont told her she
would know whether she got the job in a few weeks. Kwolek remembers this
conversation: "I decided to be very bold, and I said, 'I wonder if you
could tell me sooner, because I have some companies requesting that I
give them an answer whether I will accept their offers or not.' And this
was true!" On the spot, she got the job.
Kwolek loved her job in the Textile Lab at DuPont. "The first year,
the work was so interesting and it was so challenging. I loved to solve
problems, and it was a constant learning process. Each day there was something
new, a new challenge, and I loved that." In fact, she says, "the problem
was that I was so interested in chemistry and research that I totally
forgot about medicine." While she had assumed she would work only for
a few years until she could go to medical school, much to her surprise
she ended up staying at DuPont until she retired.
A Discovery!
Kwolek learned how to make long molecules called polymers that can be
made into fabric or plastics. In 1964, her supervisor asked Kwolek and
her coworkers to search for high-performance fibers. "At that time, we were
already thinking about strong and stiff fibers, and one of the reasons why
we were thinking in that direction was we had already seen that there was
the possibility of a gas shortage. Now, if you could reinforce tires with
a textile-type of fiber, which is lightweight, rather than steel wire, which
is very heavy, you could use much less gasoline to operate the cars or airplanes
or whatever other vehicles." Research chemists were also looking for fibers
that wouldn't melt at very high temperatures, so that they could be used
safely for objects that might get very hot or be exposed to such conditions.
During a typical day, Kwolek would combine substances to make a polymer,
melt the polymer into a liquid, and ask a coworker to spin the liquid
in a machine called a spineret. The spineret turned the liquid into
fibers. Then, other scientists would test the fibers to see how much
they weighed, how strong they were, and whether they stretched or broke
easily.
One
day, Kwolek was experimenting with two polymers that just wouldn't
melt. She had to find a solvent that would dissolve the polymers into
a liquid, instead of melting them. But something unexpected happened when
she mixed one of the polymers and the solvent. She tells the story: "And
one day, after many, many tries, I dissolved the polymer. But the solution
was unlike any other polymer solution we had seen in the laboratory. Ordinarily,
when you have a polymer solution of a flexible polymer chain, it sort
of reminds you of molasses. It may not be as thick but is generally of
a transparent or transluscent nature. With the polymer solution that I
had, it was almost like water, and it was cloudy." When she stirred the
solution, it separated into two layers: one yellow and clear, and one
opalescent and cloudy.
Curious, she took the solution to the man in charge of the spineret.
As she remembers, "he said to me, 'this will never spin, it flows like
water. And, furthermore, it has particles in it and these will plug up
the holes of the spinneret.' Well, previous to talking to him, I had filtered
the solution....and there was no separation-the whole thing went through.
I was convinced this solution would spin, because it just had the right
flow and cohesive properties." After several days arguing with the man,
"I wore him down," Kwolek laughs. "He said he would spin it. So we
spun it and it spun beautifully," she says with a big smile. "I pulled
on the fibers and they didn't fall apart, so I took them down to the physical
test lab. We had them measured for strength and stiffness. A few days
later, the results came back and I was really amazed. It was a very strong
fiber, but the thing that really amazed me was the stiffness." And, when
she baked the fiber, it became even stiffer. Kwolek had discovered
a new fiber, called an aramid fiber, and a new type of substance, called
liquid crystalline solutions.
Stephanie Kwolek is still amazed at her discovery, saying, "I knew the
direction in which to go, but I will tell you this: I never expected to
get the properties I did the first time I spun it." Her discovery was,
she says, "a case of serendipity."
It Takes A Team To Go From Fiber to Store
Kwolek is quick to point out that many people work together to
make new products, like aramid fibers. When Kwolek announced the test
results, "everyone got very excited. We got together a group of people and
we decided then there was commercial potential there, and the thing we had
to do was find the right fiber for commercialization. Everybody got into
the act, and it proved to be a very exciting, and sometimes frustrating,
time." Some people were in charge of thinking up names (like Kevlar®),
while others worked busily on submitting patent applications. There were
chemists experimenting with similar liquid crystalline solutions, scientists
thinking of ways to use and sell these superfibers, and others inventing
new ways to spin these superfibers as well as stronger testing and cutting
machines. Kwolek explains that "it turned out to be a great team effort
in the end." And, Kwolek remembers lots of hard work: "Every day, there
are highs and lows, there are times when you think the whole thing will
sink because of all the problems that develop." Going from a discovery to
a product that can be sold (product development) is a long process. It took
ten years between the time Kwolek first stirred that test tube (1965)
to the time bullet-resistant vests made with Kevlar® were available for sale (1975).
Today,
aramid fibers are used to make: boat hulls, bullet-resistant vests, coats,
and dress shirts, cut-resistant gloves, fiber-optic cables, firefighters'
suits, fuel hoses, helmets, lumberjacks' suits, parts of airplanes, radial
tires, special ropes, pieces of spacecraft, some kinds of bicycles, tennis
rackets, canoes, and skis. Aramid fibers are stronger and lighter than
steel. A vest made out of seven layers of aramid fibers weighs 2.5 pounds,
but it can deflect a knife blade and stop a .38-caliber bullet shot from
10 feet away.
Kwolek continued creating and experimenting with synthetic fibers. She
never regretted sticking with chemistry instead of going to medical
school. Although she never imagined she would grow up to be an inventor,
she explains that "when you go to work for a comapny that does chemical
research, one of the expectations is to invent things and particularly
to invent things the company is interested in. So, eventually, you do
invent something if you are interested enough and if you work hard
enough. I was thrilled when I discovered liquid crystalline solutions."
Still, she believes that "it takes a certain amount of luck, it takes
being at the right place at the right time, because you may make an
invention but no one may be interested in it at the time."
Stephanie Kwolek is proud that her invention has saved thousands of
lives and is pleased that her lifetime of work on synthetic polymers
earned her a place in the National Inventors Hall of Fame (in Akron,
Ohio). Today she takes time off from her hobbies, sewing and gardening,
to lecture about her life and invention. She is proof that a love of
science can lead you in unexpected directions that might even include
world-changing inventions! To students, Kwolek says, "Every person has
value, no matter what you do. This is what you have to remember."
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