Polymer Matrix Composites

High Performance and Full of Promise

Lighter and stronger materials are being designed that can be used at high temperatures and resist corrosion better than conventional metals or plastics in various commercial and military applications. Called polymer matrix composites, these materials consist of strong fibers embedded in a resilient plastic that holds them in place.

Polymer composites are used to make very light bicycles that are faster and easier to handle than standard ones, fishing boats that are resistant to corrosive seawater, and lightweight turbine blades that generate wind power efficiently. New commercial aircraft also contain more composites than their predecessors. A 555-passenger plane recently built by Airbus, for example, consists of 25 percent composite material, while Boeing is designing a new jumbo aircraft that is planned to be more than half polymer composites.

But composites can be costly to make and their long-term properties are not easy to predict. So, although many companies and government agencies realize the potential of these materials, they only use them in a limited number of well-proven applications.

Two new reports from the National Research Council explore how to better understand the properties of polymer composites and how industry and the U.S. military could use more composites with higher confidence as their reliability improves.

Scientists have devised various theoretical models to explain some aspects of composites' distinctive properties. Teams of scientists and engineers with expertise in chemistry, polymer physics, materials processing, and other relevant fields could combine information from these models to make more reliable predictions about how polymer composites behave, particularly under extreme conditions, says one of the reports.

Scientists and engineers also should be able to use data about composites' chemical makeup, properties, and processing conditions from large composite development projects at government agencies, such as NASA, and at private companies, such as Airbus and Boeing. The data could be assembled in a database similar to the popular gene and protein databases used by life scientists, the report adds.

In the future, polymer composites could be even tougher and lighter than today's composites, owing to M5 fibers, which promise to be the strongest and most versatile fibers ever created. These composites could improve protection against fire, blasts, and bullets for military equipment and personnel. In the next five to 10 years, the Defense Department should invest in M5 fiber research and development and should evaluate new ways of developing and purchasing high-performance fibers, the second report recommends, to improve the performance and availability of composites in the future.
  -- Patrice Pages

High-Performance Structural Fibers for Advanced Polymer Matrix Composites. Committee on High-Performance Structural Fibers for Advanced Polymer Matrix Composites, Division on Engineering and Physical Sciences (ISBN 0-309-09614-6; $18.00 plus $4.50 shipping for single copies). The committee was chaired by John W. Gillespie Jr., director of the University of Delaware's Center for Composite Materials, Newark.

Going to Extremes: Meeting the Emerging Demand for Durable Polymer Matrix Composites. Committee on Durability and Lifetime Prediction of Polymer Matrix Composites in Extreme Environments, Division on Engineering and Physical Sciences (ISBN 0-309-09715-0). Catherine Brinson, professor of mechanical engineering and materials science and engineering at Northwestern University, Evanston, Ill., chaired the committee. The report will be available soon from the National Academies Press, tel. 1-800-624-6242 or at <books.nap.edu>.

Both studies were funded by the U.S. Department of Defense.