SCIENTISTS USE GREEN APPROACH TO TRANSFORM PLASTICS MANUFACTURING PROCESS

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SCIENTISTS USE GREEN APPROACH TO TRANSFORM PLASTICS MANUFACTURING PROCESS
17 March 2007 - Carnegie Mellon Universtity

Using environmentally safe compounds like sugars and vitamin C, scientists at Carnegie Mellon University have vastly improved a popular technology used to generate a diverse range of industrial plastics for applications ranging from targeted drug delivery systems to resilient paint coatings.

The revolutionary improvement in atom transfer radical polymerization now enables large-scale production of many specialty plastics, according to the scientists, whose work appears in a special issue of the Proceedings of the National Academy of Sciences devoted to materials science.

The new "green" version of ATRP will allow existing materials to be made more efficiently, reducing industrial purification costs before and after running a reaction and permitting the production of new, unprecedented materials.

"By reducing the level of the copper catalyst used in ATRP, we have made this process at least 100 times more efficient and much more amenable to industrial processes," said Krzysztof Matyjaszewski, J.C. Warner Professor of Natural Sciences and director of the Center for Macromolecular Engineering in the Mellon College of Science at Carnegie Mellon.

Developed by Matyjaszewski, ATRP is a broadly adopted process that allows the production of specialty polymers for coatings, adhesives, lubricants, cosmetics, electronics and numerous other markets. ATRP's strength lies in its ability to combine chemically diverse subunits (monomers) into multiple arrangements that create specialized polymers. This technology enables production of "smart" materials that can respond intelligently to altered environments, such as changes in pressure, acidity, light exposure and other variables.

ATRP is being licensed to several companies that have already begun commercial production in the United States, Europe and Japan. But Matyjaszewski says large-scale production of polymers by ATRP has been limited because ATRP previously required a high concentration of copper catalyst that had to be removed from finished products.

"Our new ATRP processes significantly reduce the cost of recycling the catalyst and also decrease the release of hazardous reaction byproducts found in industrial waste," Matyjaszewski added.

During ATRP, scientists produce a complex polymer structure using a special catalyst to add one or a few monomer units at a time to a growing polymer chain. ATRP requires a balance between two species of copper (Cu) catalyst, CuI and CuII. But as an ATRP reaction progresses, CuII builds up. Typically, researchers add more CuI to compensate for this effect and maintain the balance between the two copper species. But this approach ultimately generates materials with high overall levels of copper, levels that are too costly to remove efficiently on a large-scale industrial basis.

The PNAS report highlights the team's novel use of "excess reducing agents" to lower the amount of copper catalyst from 5,000 parts per million (ppm) to 10 ppm. The team showed that you can steadily add environmentally benign "reducing" agents, vitamin C, sugars or standard free radicals, to chemically reduce CuII to CuI. This unprecedented approach continuously reduces CuII to CuI at the same rate CuII forms while retaining the desired balance between the two states. Ultimately, this technique dramatically lowers the overall amount of Cu catalyst used in ATRP by as much as 1,000 times.

The team's new technology virtually eliminates the need to remove miniscule amounts of catalyst remaining in a product. For example, many ATRP-generated plastics for medical implants would be acceptable from a health perspective because they contain so little copper. However, if the target application, such as a coating for a biomedical stent, absolutely requires the removal of residual catalyst, companies will now have much less of it to take out, significantly lowering removal costs, according to the authors.

The new ATRP technique also allows for production of higher molecular weight chains, thereby extending the range of accessible materials that could be made using this method. For example, chemists could grow high molecular weight polymers with precise control, providing even larger templates for nanoscale carbon structures used in computer screen field emission displays and semi-conductors that regulate the flow of electricity in sensors, some only a fraction of the width of a hair.

ATRP differs significantly from conventional polymer manufacturing methods. This "living," synthetic process can be shut down or restarted at will, depending on how the temperature and other conditions of the reaction are varied. ATRP is an exceptionally robust way to uniformly and precisely control the chemical composition and architecture of polymers as well as the growth of every polymer chain, all while employing a broad range of monomers.

Much of the research progress and commercial success related to ATRP is due to two research consortia Matyjaszewski has initiated and led. These successful consortia have allowed many companies to incorporate ATRP methodologies into the development of new products for their specific markets. Companies from around the world send their employees to train in Matyjaszewski's laboratory. For more information, visit www.chem.cmu.edu/groups/maty/center/.

This research was supported by the National Science Foundation and the Carnegie Mellon consortium of industrial partners.

http://www.cmu.edu

About: Carnegie Mellon Universtity
The Carnegie Institution of Washington (www.carnegieinstitution.org) has been a pioneering force in basic scientific research since 1902. It is a private, nonprofit organization with six research departments throughout the U.S. Carnegie scientists are leaders in plant biology, developmental biology, astronomy, materials science, global ecology, and Earth and planetary science.

Since its founding in 1900 by industrialist and philanthropist Andrew Carnegie, Carnegie Mellon University has been a pragmatic institution, adapting rapidly to change. In fewer than 100 years it has changed its name three times--each transition marking a milestone in the institution's 20th century evolution.

Whether it was Carnegie Technical Schools, as it was in its first 12 years, Carnegie Institute of Technology, its name from 1912 to 1967, or Carnegie Mellon University, three primary purposes formed its foundation. Throughout this century, Carnegie Mellon has focused on delivering distinctive and first-quality education, fostering research, creativity and discovery, and using the new knowledge created on campus to serve our larger society.

When Arthur A. Hamerschlag served as the school's first president, Carnegie Technical Schools' 12 professors and six administrators sought to educate the sons and daughters of Pittsburgh workers for employment in the region's growing industries.

These educators served the vision of Carnegie by organizing into four faculties: the School of Science and Technology, the School of Fine and Applied Arts, the School of Apprentices and Journeymen, and the Margaret Morrison Carnegie School for Women.

In its earliest years, the institution served primarily part-time and undergraduate students. The faculty, many of whom did not have doctor's degrees, focused on teaching and curriculum development.

But research efforts began as early as 1916 when the Division of Applied Psychology of the Carnegie Institute of Technology developed rating scales for job placement. This rating system was used to classify two million men for placement in the armed forces during World War I. Research bureaus were organized in coal mining, nuclear physics, applied chemistry and metallurgy.

And by granting the nation's first undergraduate degree in drama in 1917, the institution began a tradition of leadership in the arts that spanned the century.

Through research and the education of its students during the administration of President Thomas S. Baker in the 1920s and '30s, the institution began its strong tradition of transferring knowledge and skills to industry and government.

Building on this firm foundation, the administration of President Robert E. Doherty introduced a new approach to education that would be used as a model by similar institutions around the nation. The Carnegie Plan for Professional Education, initiated in 1939-40, required engineering and science students to take a quarter of their courses in a new Humanistic and Social Relations sequence. In addition, its curriculum focused on teaching students problem-solving techniques, a hallmark of the Carnegie Mellon educational experience today.

While the Doherty administration has been credited with this educational innovation, it also oversaw growth in the institution's research capability. Between 1936 and 1950, the number of graduate students grew from 36 to more than 260. The research budget ballooned from $156,000 to $1 million.

In the 1950s, the newly formed Graduate School of Industrial Administration, endowed by William Larimer Mellon, emerged as one of the three or four best business schools in the nation. (In 2004 the school was renamed the David A. Tepper School of Business after benefactor and alumnus David Tepper (MBA '82).) Today, the school is recognized as a pioneer in the field of management science and one of the top business schools in the world.

The Warner administration oversaw the institution's burgeoning research enterprise. This period of research growth was aided by the work of the institution's Computation Center, founded in 1956 to provide computing services to the campus. A major grant from benefactor Richard K. Mellon in 1965 aided the establishment of a Computer Science Department, a department which would be the genesis of Carnegie Mellon's worldwide reputation in computer science.

By the end of the Warner administration and the start of the administration of President H. Guyford Stever in 1966, Carnegie Tech had most elements of a university. Its merger in 1967 with the Mellon Institute created Carnegie Mellon University and brought a $60 million endowment, extensive research facilities and renowned research personnel to the institution.

Five years later, President Richard M. Cyert (1972-90) began a tenure that was characterized by unparalleled growth and development. The university's research budget soared from about $12 million annually in the early 1970s to more than $110 million in the late 1980s. The work of researchers in new fields such as robotics and software engineering helped the university build on its reputation for innovative ideas and pragmatic solutions to the problems of industry and society. Carnegie Mellon began to be recognized as a truly national research university able to attract students from across the nation and around the world.

The Cyert administration stressed strategic planning and comparative advantage, pursuing opportunities in areas in which Carnegie Mellon could outdistance its competitors.

An archetypal example of this approach was the introduction of the university's "Andrew" computing network in the mid-1980s. This pioneering network, which linked all computers and workstations on campus, set the standard for educational computing and firmly established the university as a leader in the uses of technology in education and research.

Education and teaching also benefited in this period with the establishment of a University Teaching Center to improve faculty teaching and the renovation of many of the university's classrooms.

Cognizant of the university's heritage, President Robert Mehrabian (1990-97) invited alumni from the era of the institution's first president, Arthur A. Hamerschlag, to attend his inauguration in 1990. President Mehrabian emphasized Carnegie Mellon's traditional strengths in education, research and service to society while focusing on initiatives for leadership in the 21st century.

With the appointment of the university's first Vice Provost for Education, President Mehrabian placed renewed emphasis early in his administration on the quality of undergraduate education. He also moved aggressively to complete the most ambitious campus building plan since the Warner era. The University Center, which opened in August 1996, and the Purnell Center for the Arts, to be completed by the fall of 1999, are keys to enhancing the quality of life on campus, another priority of the Mehrabian administration.

Confronted by shrinking governmental support of university research, President Mehrabian diversified the university's research agenda. He stressed the need to build strong relationships with the business world, matching industry's needs with the university's areas of research strength. He also put new emphasis on productivity, improvement of administrative services and strategic management of university resources.

President Mehrabian established strong, new partnerships with the greater Pittsburgh community. He led a community-wide economic development initiative, spurred collaboration with primary and secondary schools, and worked closely with local community groups.

On April 15, 1997, Jared L. Cohon, former dean of Yale University's School of Forestry and Environmental Studies, was elected by the university's Board of Trustees to succeed President Mehrabian, who resigned to spend more time with his family in California.

"Since I was chosen, since this wonderful event has occurred, it has made me reflect on why you are choosing me," President Cohon said in his first speech to the university community. "And I've said to people since this was announced that the more I think about it, the more I realize how well I think this institution and I fit together. We'll see if that's true. I think it is.

"When I was at Johns Hopkins we used to always hold up Carnegie Mellon as an example," Cohon said. "So, for many years I've ... been jealous of what has been accomplished here across departmental lines. I celebrate that. I think it is so valuable in every aspect of this university and it will position Carnegie Mellon to be even better...."

During Cohon's presidency, Carnegie Mellon has continued its trajectory of innovation and growth. Today, President Cohon is leading implementation of a comprehensive strategic plan that aims to leverage the university's existing strengths to benefit society in the areas of biotechnology and the life sciences, information and security technology, environmental science and practices, the fine arts and humanities.

The university is also committed to broadening and enhancing undergraduate education to allow students to explore various disciplines while maintaining a core focus in their primary area of study. Realizing that today's graduates must understand international issues, Carnegie Mellon is committed to providing a global education for its students and is striving to expand its international offerings and to increase its presence on a global scale. Increasing diversity, in all aspects, and fostering the economic development of southwestern Pennsylvania, are also top priorities.

Over the years Carnegie Mellon's leaders have reflected Andrew Carnegie's original dedication and commitment to this institution. In his 1900 letter to the mayor of Pittsburgh establishing Carnegie Technical Schools, Andrew Carnegie wrote, "My heart is in the work." These words have been echoed by students, faculty and administrators throughout this century and they live on the Carnegie Mellon campus today.

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