Chemist, the inventor of the material used in steel vests: Who is Stephanie Kwolek?

Stephanie Kwolek was born on July 31, 1923, in New Kensington, Pennsylvania. She was born as one of the two children of John Kwolek, a Polish immigrant father, a naturalist, and Nellie Zajdel Kwolek, a Polish immigrant mother, a tailor. When Kwolek was a child, she and her father would spend hours exploring the natural world. They would also spend together exploring nearby forests, collecting plants and observing animals, which they would later name and characterize in a notebook Kwolek kept as a child. Kwolek, who lost her father when she was ten, would carry her interest and love for science to the end of her life, as she inherited it from her father. Additionally, she attributed her interest in fashion design to her mother who works as a seamstress. After her mother told Kwelok that she was too perfectionist to pursue a career in fashion, Kwolek decided to become a doctor.

In 1946, Kwolek graduated from Carnegie Mellon University Margaret Morrison Carnegie College with a BS in chemistry. Her future mentor, William Hale Charch, offered Kwolek a job at DuPont's Buffalo, New York facility in 1946. The firm, a chemical company, was trying to find a petroleum-based polymer fiber that was lighter and more durable than steel. Considering that many men were fighting in wars in different countries, there were vacancies in the company and employers were more open to hiring women. The firm introduced nylon shortly before the Second World War, and it exploded into a variety of textile applications.

It also prompted the need for lightweight, wearable armor to protect personnel and equipment, due to the protracted Second World War. As the war raged, soldiers participating in the battle had to wear body armor because it was thought that nothing else was strong enough to stop a bullet. However, with this armor, there was not enough light material to wear in battle. While steel was the only armor material available, its weight limited its use to tanks. Even then, steel could be pierced with special weapons.

Kwolek considered working at the firm temporarily to raise money for further work, so she joined the firm in 1946. After finding polymer chemistry interesting, she decided to continue and moved with her research group to Wilmington, Delaware in 1950. The paper "The Nylon Rope Trick" demonstrated a way to produce nylon in a beaker at room temperature. Subsequently, the process was extended to high molecular weight polyamides in a still common grade experiment.

Kwolek wanted to engage in the search for a new condensation process that takes place at lower temperatures. For example, the melt condensation polymerization process used in the preparation of nylon performed above 200°C. Low-temperature polycondensation processes using very rapidly reacting intermediates made possible the easy preparation of polymers that cannot be melted and only begin to decompose at temperatures above 400°C.

Kwolek is best known in the 1950s and 1960s for her work with "aromatic polyamides", a type of polymer that could be spun into strong, tough and flame resistant fibers. In her laboratory work, she found that due to the presence of bulky benzene rings in its molecular chains, it forms tough fibers from this molecule. However, it could be prepared from solution as aramids melt only at very high temperatures. Kwolek reported the solvents and polymerization conditions suitable for producing "poly-m-phenylene isophthalamide", a compound the company launched in 1961 as a flame resistant fiber with the trade name 'Nomex'. Kwelok received a publication award from the American Chemical Society (ACS) in 1959, the first of many awards. 

In 1965 the first fibers began to be tested. Later, she furthered her work with "poly-p-benzamide" and "poly-p-phenylene terephthalamide". She noted that these adopt highly ordered rod-like molecular arrangements in solution. Fibers exhibiting unprecedented stiffness and tensile strength were spun from these two "liquid crystal polymers", the first polymer ever prepared. The innovative polymer 'Poly-p-phenylene terephthalamide' as invented by Kwolek is commercially available under the name "Kevlar".

In 1964, in anticipation of a gasoline shortage, they began searching for a light but strong fiber to replace the steel used in tires. The polymers she worked with formed a liquid crystal when in solution, which at that time had to be melted above 200°C (392°F). This produced weaker and less rigid fibers. She decided to lower these temperatures between 0 and 40°C (32 and 104°F) as a unique technique in their new project and melt-condensation polymerization process.

In a speech she gave in 1993, she said that the solution is unusually cloudy, iridescent when mixed, and has the appearance of buttermilk and should normally be clear or translucent. In addition, she reported that the solution she prepared was like a dispersion and could be completely filtered through a fine-mesh filter, and that this liquid was a crystalline solution, but she did not know that at the time.

Such a fuzzy solution was usually discarded. Kwolek's use of the level for her solution was denied, as the solution was thought to clog the machine. However, Kwolek managed to persuade Charles Smullen, the technician running the level, to test it. She was very surprised to find that the new fiber would not break, as nylon normally does. In addition to being stronger than nylon, Kevlar was five times stronger in weight than steel. The firm understood the significance of her discovery, a new field in polymer chemistry quickly emerged.

In 1971, modern Kevlar was introduced to the world. Kwolek also learned that fibers can be made even stronger by heat treatment. The polymer molecules, in the form of sticks, were highly oriented, giving to the new polymer extraordinary strength. Kwolek decided to continue research on thermotropic Kevlar derivatives containing aliphatic and chlorine groups.

Kwolek was not very involved in developing practical applications to the new polymer. Saying that after senior company executives heard of the discovery, a whole group was assigned to work on different aspects, Kwolek continued her research on Kevlar derivatives. Since she transferred the patent of Kevlar to the company, she could not profit from the products from the company.

This new polymer is used in more than 200 applications, including tennis rackets, skis, boats, airplanes and bulletproof vests. In addition, it continued to be used on car tires, fire boots, hockey sticks, cut-resistant gloves, and armored vehicles. The new material was also used for protective building materials such as bomb-proof materials, hurricane-proof chambers, and bridge reinforcements. The week Kwolek died, the company sold its one millionth bulletproof vest made with Kevlar. This polymer was also used to make cell phone cases. For example, Motorola's Droid RAZR is a phone with a Kevlar unibody.

For her discovery of Kevlar, Kwolek was recognized as "an enduring experimenter and role model whose discovery of liquid crystal polyamides led to Kevlar aramid fibers" and was crowned DuPont's Lavoisier Medal for outstanding technical achievement in 1995. She also managed to become the first woman to win this medal. After her death in 2014, she remains the only female employee to receive this honor. While her discovery generated several billion dollars in revenue for her then-employer company, Kwolek never directly benefited from it financially because she had filed her patent.

In 1980, Kwolek received the "Chemical Pioneer Award" from the American Institute of Chemists and the "Creative Invention Award" from the American Chemical Society. In 1995, Kwolek made her name once again by being inducted into the National Inventors Hall of Fame. The following year, she won the National Medal of Technology and the IRI Achievement Award. In 1997 she was crowned with the Perkin Medal from the American Chemical Society she. 

Kwolek has received honorary degrees from Carnegie Mellon University, Worcester Polytechnic Institute, and Clarkson University. She was honored by the Royal Society of Chemistry with the biennial "Stephanie L Kwolek Award" "in recognition of the outstanding contribution of a scientist working outside the UK to the field of materials chemistry". Also, Kwolek is cited as one of the "175 Faces of Chemistry" of the Royal Society of Chemistry.

As the firm is at the cutting edge in these matters, Kwolek never changed her position and spent her entire career with the company. During his 40-year career in the company, she made different contributions to products such as Spandex (Lycra), Nomex, Kapton (mit) as well as Kevlar. After retiring in 1986, she continued to advise the company. She has also served on both the National Research Council and the National Academy of Sciences she. That same year, she retired from the company as a research assistant. Working as a research scientist for 40 years, Kwolek applied for and received 28 patents.

A frequent chemistry lecturer to students, Kwolek designed and wrote numerous classroom demonstrations that are still used in schools today, such as the 'Nylon Rope Trick'. Kwolek, who never married and devoted herself to her profession, died on June 18, 2014 at the age of 90. Kwolek's burial is at St Joseph's in Brandywine.