The University Distinguished Professor of Chemistry at Virginia Tech started to study polymerizations for synthetic rubber with Goodyear in 1959. He and his students are now making advancements in synthetic chemistry aimed at making polymers both conductive and strong enough to be used as advanced materials in fuel cells.
McGrath has received the American Chemical Society (ACS) Award in Applied Polymer Science for his contributions to chemistry -- physical and polymer science principles -- that have made it possible to create new materials. During the 223rd ACS national meeting, April 7-11 in Orlando, there will be a special symposium recognizing McGrath's work and influence on Tuesday, April 9 in Convention Center room 312 B/C, and on Wednesday, April 10, in Convention Center room 314 A beginning at 8:30 a.m. both days. McGrath will give the award address at 3:55 p.m. Tuesday.
He says a turning point in his career came after he had earned his B.S. and was working with Rayonier, Inc. in cellulose fibers and films, products known as rayon and cellophane. He heard a talk by Professor Herman Mark on the nature and opportunities associated with block and graft copolymers.
McGrath explains, "Block copolymers allow you to have a chance at the best features of two entirely different materials, such as the rubbery properties of an elastomer and the rigid properties of a plastic material. That is a major reason why block copolymers have become industrially important," McGrath says.
"Also, processing is fast and economical and the product can be recycled. In earlier polymeric systems, such as vulcanized rubbers, you could not separate the components for reprocessing and reuse. Once processed, the material was set and could not be recycled."
He was studying chemistry at the University of Akron and working at Goodyear when he became involved at the early stages of thermoplastic elastomer development. His Ph.D. research under the late Professor Maurice Morton generated some of the first academic results dealing with the synthesis and chemical structure/physical property relationships in thermoplastic elastomeric block copolymers. First presented in 1967, the work has been frequently quoted since it was published in the Journal of Polymer Science in 1969.
Thermoplastic elastomers are largely based on block copolymer chemistry. For example, rubber and plastic copolymers can be processed at temperatures appropriate for the plastic and, when cooled, solidify and strengthen the rubber. Imagine plastic+rubber+plastic (p+r+p) or rigid+soft+rigid at the molecular level. The important difference between block copolymers and random polymers is the molecule arrangement. In block copolymers, the arrangement is ppppp+rrrrrrr+ppppp, in blocks, instead of random.
"That was the practical side of my Ph.D. thesis," McGrath says. The thesis explored the synthesis of block copolymers by living anionic organolithium chemistry. Using the example above, "A living polymer is an active chain that has a 'living end', which allows you to grow the plastic part, put on an end for the rubber part, and then go back to the plastic part," he says. "The detailed chemistry involves lithium chemistry."
McGrath spent eight years at Union Carbide before joining Virginia Tech's faculty in 1975. McGrath has been a leader in determining the chemistry required to maintain the integrity and qualities of the polymer material while preserving the desired properties of each component, all with processing ease and economy, and recyclability. "Whether the product is soft or hard depends largely on the percent of the soft or hard material," he explains.
In 1989, he and colleagues in chemistry and engineering at Virginia Tech established the National Science Foundation Science and Technology Center for High Performance Polymeric Adhesives and Composites, and changed his focus to phosphorous-containing polymers and thermoplastic toughened adhesives and structural composites, particularly for aerospace. "Phosphorous can impart fire resistance to materials, and other high performance characteristics, such as radiation and atomic oxygen resistance. NASA found it useful in outer space."
The NSF center worked extensively on new material systems designed for maximum durability, reliability, and safety. During the course of a decade, the center faculty graduated 120 students and published more than 500 papers. Strengthened adhesive and composite concepts developed by the center have been critical for the military, such as on F18, and on Airbus aircraft. Improved materials have been commercialized by such companies as Mitsubishi Heavy Industries and Cytec.
As he worked to improve the processibility of materials, McGrath has also worked to make processing safer. These components were formed as powders, using pressure and heat to form structural materials, thus avoiding the use of solvents in processing. As a result, he has learned a lot about water-based dispersion, he says.
In the 1980s, McGrath also worked on desalination membranes. "Sulfonated polymers contain ionic groups that are hydrophilic (They like water.). If you want something to interact with water, you have to make it like water. Many polymers are hydrophobic, but if you add sulfonic acid sites, they will let the water through their molecular structure, and can be designed to repel salt.
"The same sulfonic groups can be proton conductors," he realized.
Proton exchange membranes (PEMs) are the critical component of fuel cell systems that break up hydrogen atoms, for example, into the protons and electrons used to create energy, with by products of water and heat. McGrath directs the Materials Research Institute at Virginia Tech, which is using new polymer PEMs instead of the expensive teflon-like materials previously required. "These new sulfonated polymers are excellent proton conductors for fuel cells."
And the creation of copolymers that like water (to a degree) brings us back to block copolymers. "It would be desirable (We would like?) to combine the attributes of rigid strength and the ability to withstand high temperatures with the conductive hydrophilic material. When the temperature goes up, a random copolymer of these materials may become too soft to be mechanically stable, even if it has the right electrical properties."
But, based on block copolymer chemistry, "we've made some progress," says McGrath.
Several funding agencies agree. In 2001, McGrath's team, which includes researchers at Los Alamos National Lab and Virginia Commonwealth University, as well as from chemical and mechanical engineering at Virginia Tech, received a $600,000 grant from the National Science Foundation, $2 million from the Department of Energy, and $500,000 from one industry partnership alone — in addition to support for specific projects from such agencies as the Office of Naval Research and NASA.
McGrath and colleagues report that the new polymers that can operate at higher temperatures than present day PEMs, and are more conductive. They reported several successful strategies for creating better PEM materials at the American Chemical Society meeting in late August and a number of papers are scheduled for the 223rd national ACS meeting, April 7-11 in Orlando . For PEM now read: polymer electrolyte membranes.
The Ethyl Chaired Professor of Chemistry at Virginia Tech, McGrath also received the ACS Division of Polymer Chemistry’s Distinguished Service Award. He chaired that division in 1987 and organized a series of outstanding division workshops. Indeed, education has been a major component of his career. McGrath influenced the polymer education program at Virginia Tech, chaired three Gordon conferences and conducted summer workshops for industry scientists and for NSF outstanding undergraduates from across the country. He has supervised more than 100 Ph.D. students and 60 postdocs.
His honors include the SPE International Award for outstanding contributions in the field of plastics, the ACS Division of Polymer Chemistry’s Herman Mark Award recognizing outstanding research and leadership in polymer science, the Virginia's Outstanding Scientists designation from the Science Museum of Virginia, and the Outstanding Achievement Award by the Society of Plastic Engineers.
McGrath was elected to the National Academy of Engineering in 1994. He has served on numerous advisory boards in industry and government, including the National Materials Advisory Board of the National Research Council.
He has 50 patents and 400 publications, including having written or edited nine books. He edited an important book on living anionic polymerization, Anionic Polymerization, Kinetics, Mechanisms, and Synthesis, published by ACS in 1980, and co-wrote with Allen Noshay a book on block copolymers, Block Copolymers: Overview and Critical Survey, published by Academic Press in 1977. In 1999, he wrote Advances in Polymer Science, Vol. 141, published by Springer Verlag.
PR CONTACT: Susan Trulove (540) 231-5646 STrulove@vt.edu
Contact Dr. James E. McGrath at jmcgrath@vt.edu, 5540-231-5976