Profiles in Science
Ruth Benerito: Using Basic Physical Chemistry to Solve Practical Problems
In the 1930s, the Great Depression had a stronghold on countries all over the world. At its worst, as much as 25% of the United States’ working-class was unemployed; in other countries that rate rose as high as 33%. Most of those who were able to find or hold on to work saw their hourly wages cut significantly, and many were left destitute with only a shanty to call home.
During this same era, the US cotton industry took a hit as well. Technological advances had allowed for the development of synthetic fibers, and consumers were drawn to their easy-care properties when these new materials were introduced to the apparel market. Cotton, which had ruled the textile industry for centuries because of its desirable qualities, was suddenly too “high maintenance.”
If the cotton industry was going to survive, something significant was going to need to happen. That “something” came from a team of scientists at the Southern Regional Research Center (SRRC) in New Orleans, Louisiana, led by chemist Ruth Benerito.
Laying the foundation
Ruth Rogan Benerito was born in 1916 to parents with a strong belief in education and in women's rights. She described her father, civil engineer John Edward Rogan, as a pioneer in women's liberation, and her mother, artist Bernadette Elizardi Rogan, as a “truly liberated woman” (Newcomb Oral History Project, 1986). Though Benerito was raised in a time when very few women studied the hard sciences, and there were even fewer jobs for those who did, this didn't stop her from pursuing science at Sophie Newcomb College, the women’s college of Tulane University in New Orleans.
Originally, Benerito's main interest was in mathematics. However, she quickly discovered that the only career for math majors at that time was actuarial work with an insurance company. Sitting at a desk and estimating probabilities was not the job for her. She liked to solve practical problems, and chemistry was one way to do it.
When Benerito received her BS in chemistry in 1935, one in five Americans was unemployed (Levine, 2009). Finding work during the Great Depression, which continued into the mid-1940s, was difficult for men and nearly impossible for women. The logical career path for a woman with a college degree was teaching, but in an effort to save costs high school science was often taught by football coaches, so Benerito pursued graduate study for a year and then trained to become a laboratory technician.
After a few years, Benerito was able to secure a teaching position at a high school in New Orleans, where she was required to teach driver’s safety as well as science. The problem? Benerito didn't know how to drive. She was the first safety driving teacher in the state of Louisiana, and the first one to drive into a ditch.
While teaching full-time, she earned her master’s degree by taking night classes. She and Margaret Strange (Klappard) – later vice president of the University of Alabama Medical School – were the only women permitted to take physical chemistry at Tulane University because it was not offered at Newcomb. “We took it with the engineers. They didn't like it one bit,” Benerito recalled (Newcomb Oral History Project, 1986).
During the early World War II years, Benerito focused on teaching college chemistry. But as the war waged on, her family moved to Chicago and, while continuing to teach, she earned a PhD in physical chemistry from the University of Chicago by taking classes one summer at a time. Chicago at that time had the greatest accumulation of Nobel laureates because of the Manhattan Project. Benerito loved the intellectual climate and being taught by "the greatest chemists of the last century" in very small classes, sometimes with only one other student (USDA interview, 2004).
Tackling the problems of her time
In 1953, fed up with wage discrimination, Benerito left full-time academia and became a researcher at the Southern Regional Research Center (SRRC) in New Orleans, remaining there until she retired in 1986. Before turning her attention to cotton, she helped develop a way to deliver fat emulsions intravenously to sustain soldiers who had been seriously wounded in the Korean War.
The SRRC began operating in 1941 as one of four centers established by the United States Department of Agriculture (USDA) across the nation to address regional agricultural problems and find new uses for local crops. For New Orleans, that focus was on peanuts, sweet potatoes, and cotton. In 1958, Benerito became leader of the SRRC’s Cotton Chemical Reactions Laboratory (Figure 2).
While Benerito was at the helm, around 80 percent of the center’s budget went to cotton research. She referred to the 1950s as "the golden age of science,” when the US government poured money into scientific research after the Soviet Union’s success with Sputnik, and scientists, not business administrators, determined how research funds would be spent (American Chemical Society, 2004).
The trouble with cotton
Cotton fabric had been king for centuries because of its desirable qualities: It is comfortable, breathable, renewable, and easy to dye. However, it also wrinkles very easily and requires a lot of ironing to look crisp and sharp – problems synthetic fibers do not possess. This is because of the structure of cotton fibers. Cotton is made of strands of polymers, or polysaccharide cellulose chains, held together by weak hydrogen bonds (see Figure 3). These hydrogen bonds break easily during washing and drying, leaving cotton fabric wrinkled (Wolf, 2013).
From the time synthetic fibers had been introduced in the 1930s, the cotton industry had been on a steady decline, and synthetics gained a huge advantage when Dacron polyester arrived on the scene in 1951. Cotton needed a boost to remain a contender in the textile market. If the downward trend continued, it was projected that cotton would claim just 20 percent of the US market share by the end of the century and very little would even be grown in the US by the year 2000 (American Chemical Society, 2004). Benerito's team came to the rescue when they discovered a key to taking the rumple out of cotton.
What made cotton fabric difficult to work with?
Cross-linking: A new process for treating cotton
Advances in permanent press involved many cotton scientists in different groups at SRRC. One of these was chemist Ralph Berni, who worked alongside Benerito for many years in the Cotton Chemical Reactions group. Their work resulted in numerous publications and patents in the areas of permanent press, flame retardancy, epoxide resins, and ion exchange cottons. The group’s focus was on chemically modifying cotton so it could compete with synthetic fabrics. Berni says, "Ruth’s contributions in this area focused on the understanding of the cross-linking process and its overall importance to the cotton industry."
Under Benerito's leadership, a team of chemists found one important piece of the “how to wrinkle-proof cotton” puzzle when they developed a new process for treating the fibers. The process, called cross-linking, joins new ring-shaped organic compounds to the polymer chains, replacing the hydrogen bonds with strong new chemical bonds (see Figure 4). (For more about basic organic compounds, see our Carbon Chemistry: An Introduction module.) Cross-linking keeps the polymers from breaking apart, so the cotton fabric comes out of the dryer without wrinkles.
Because of the cross-linking process, people could now have the comfort of cotton without the inconvenience. As a result, the world once again began to use more cotton than any other fiber. As recently as 2012, the US cotton industry generated about 200,000 jobs and more than $25 billion in products and services (USDA Economic Research Service).
To compete with synthetic fabrics, cotton was chemically modified through a process called
Acknowledging the contributions of others
Benerito was the first to admit that she did not singlehandedly invent wrinkle-resistant cotton. In fact, a Shaker community in Maine developed a water- and wrinkle-proof finish for cotton in the 1800s by applying a zinc chloride solution to cotton cloth and heating it (Becksvoort, 1998). And in the early 20th century, others tried to tame cotton: French chemists tested the effects of formaldehyde on cotton, while British scientists tried other methods to make cotton more cooperative (American Chemical Society, 2004). Benerito clarified her role:
I don't like it to be said that I invented wash-wear because there were any number of people worked on it and the various processes by which you give cotton those properties. No one person discovered it or is responsible for it, but I contributed to new processes of doing it. (USDA interview, 2004)
Benerito always acknowledged the contributions of the other cotton chemists and physicists, but the rumors persisted when the popular media misunderstood the science behind her work and attributed her disavowals to a natural modesty that accompanied her quiet demeanor.
Benerito's breakthrough in attaching organic chemicals to change the properties of cotton has served as the basis for ongoing advances in chemical applications to textiles and other materials. Beyond wrinkle resistance, cotton can assume other valuable properties such as stain-resistance, flame-resistance, and increased durability. Her advances in chemistry yielded, and continue to yield, new developments: Treatments for cotton at different stages of planning and development include medical dressing to promote wound healing and stop bleeding, a quick-drying treatment, and a way to wick moisture away so that cotton can compete in the athletic wear market, which is currently dominated by synthetics (Agricultural Research Service, 2010-2015). Her process also led to advances in treatments for wood, film, paper, and epoxy plastic.
Ruth Benerito was the first person to attempt to wrinkle-proof cotton.
A life of achievements
Benerito’s contribution to the science of cotton is recognized as one of the most important technological advances of the 20th century, earning her a place in the National Inventors Hall of Fame in 2008. She held more than 50 patents, authored more than 200 publications in professional journals, and became a sought-after speaker, in large part because she was keenly interested in scientists’ duties to society.
Among her many accomplishments, Benerito received the Federal Woman’s Award, presented by President Lyndon B. Johnson (1968), the Southern Chemist Award by the American Chemical Society (1968), the Garvan Medal for Distinguished Service to Chemistry by Women Chemists from the American Chemical Society (1970), and the Southwest Regional Award from the American Chemical Society (and the first woman to receive this honor, 1972). In addition, she was awarded the Lemelson-MIT Lifetime Achievement Award for Invention and Innovation (2002) and was inducted into the USDA’s Agricultural Research Service (ARS) Science Hall of Fame (2004).
Reflecting on her many achievements, she said:
I believe that whatever success that I have attained is the result of many efforts of many [people]. My very personal success was built from the help and sacrifices of members of my family, and professional accomplishments resulted from the efforts of early teachers and the cooperativeness of colleagues too many to enumerate.
Her greatest accomplishment, according to Benerito, was "the application of basic physical chemistry to solve practical problems."
Wrinkle-resistant cotton is one of the most significant developments of the 20th century. In the midst of an economic and social climate that provided few opportunities for women in science, chemist Ruth Benerito developed a method of wrinkle-proofing cotton, which was being edged out of the clothing market by synthetic fabrics. This profile describes the life of the chemist who is often credited with saving the US cotton industry. It explains the cross-linking process that made “wash-and-wear” cotton fabric possible.