Larger, yet lightweight wind turbine blades

New Bayer material offers distinct advantages for use in wind turbine blades – testing shows lighter weight, enhanced strength and improved fatigue resistance are possible

Pittsburgh, June 1, 2012 — When producing wind energy, bigger is better. Wind farm operators and suppliers are seeking larger wind blades to improve efficiency, and they are expressing strong interest in material improvements to meet their needs.

Longer blades can achieve larger sweep areas. However, gravity-induced bending loads on blades create dramatic increases in dynamic stress, heightening market demand for a material that reduces blade mass while retaining strength.

Current materials are not designed to withstand these increased demands. Lighter weight composite materials with increased stiffness and enhanced fatigue endurance properties offer a promising solution. Bayer MaterialScience LLC's newly developed class of polyurethane systems offer stronger, tougher polymers ideal for producing polyurethane composites suitable for manufacture of large parts by vacuum infusion.

Bayer's Baydur® polyurethane system possesses low-viscosity and long-gelling properties. Comparative testing against epoxy and vinyl ester-based composites reveals the Baydur polyurethane system provides several key advantages, including,

  • Superior tensile fatigue, interlaminar fracture toughness and fatigue crack growth;
  • Ultra-low volatile organic compounds (VOCs);
  • Faster infusion time;
  • Use of sustainable raw materials from renewable resources.

Bayer Principal Scientist Dr. Usama Younes will share the results of a recent study, funded in part by a Department of Energy (DOE) grant that details the development of this Baydur polyurethane system during two presentations. His first presentation, "Polyurethane structural components for wind turbine blades," is during the Sandia National Laboratories Wind Turbine Blade Workshop, being held through today, in Albuquerque, N.M. He also will present during a poster reception at the American Wind Energy Association WindPower 2012 conference being held June 3-6 in Atlanta.

As part of his presentations, Dr. Younes will explain tests comparing properties of incumbent epoxy and vinyl ester resin systems with a polyurethane resin system. Younes will detail compressive strength tests of polyurethane resins compared with epoxy resins, showing that polyurethane systems are roughly one-third stronger than epoxy resins. Other testing compares polyurethane with unsaturated polyester and indicates that polyurethane composite's impact strength is nearly double that of unsaturated polyester composites. Additional testing also shows that polyurethane-based carbon fiber systems offer enhanced fatigue resistance compared with epoxy resins.

Younes also will discuss testing that included two sets of long flow, vacuum-infusion experiments designed to compare the flow rates of the different resins, and studies that show a clear trend toward improvement in the fracture toughness of composites from the presence of multi-walled carbon nanotubes.

"This research is important across the wind energy value chain, demonstrating that polyurethanes may provide distinct technology advantages that current resins in use would not, especially as the market continues to increase the size of turbine blades," said Sharon Papke, head, Wind Energy, Bayer MaterialScience LLC. "At Bayer we leverage a broad business portfolio to provide solutions to the wind energy market and meet industry needs."

Development of the Baydur polyurethane system is the result of a DOE grant (DOE award number DE-EE0001361) for the development of new, stronger composite materials for wind blades. The grant also helped fund additional research comparing the performance of new polyurethane resins systems with those of traditional epoxy and vinyl ester resins used for wind blades. The grant's scope included investigating the effect of carbon nanotubes on the performance of polyurethane, epoxy and vinyl ester composites.

About Bayer MaterialScience LLC:

Bayer MaterialScience LLC is one of the leading producers of polymers and high-performance plastics in North America and is part of the global Bayer MaterialScience business with approximately 14,800 employees at 30 production sites around the world and 2011 sales of 10.8 billion euros. Bayer MaterialScience's 2011 sales in North America were $2.9 billion. The company manufactures high-tech polymer materials and develops innovative solutions for products used in many areas of daily life. The main segments served are the automotive, electrical and electronics, construction, medical, and sports and leisure industries. Sustainability is central to Bayer MaterialScience LLC's business and is based around the key areas of innovation, product stewardship, excellence in corporate management, social responsibility and respect for the environment.

Contact:

Thomas Erdner, Phone: 412-777-5200
E-mail: thomas.erdner@bayer.com

For more information about Bayer MaterialScience LLC's composites technology, call 412-777-7454 or visit www.bmsnafta.com.

Forward-Looking Statements

This news release may contain forward-looking statements based on current assumptions and forecasts made by Bayer Group or subgroup management. Various known and unknown risks, uncertainties and other factors could lead to material differences between the actual future results, financial situation, development or performance of the company and the estimates given here. These factors include those discussed in Bayer's public reports which are available on the Bayer website at www.bayer.com. The company assumes no liability whatsoever to update these forward-looking statements or to conform them to future events or developments.

Acknowledgment: "This material is based upon work supported by the Department of Energy under Award Number DE-EE0001361."

Disclaimer: "This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof."

Editor's Note: Follow news from Bayer MaterialScience LLC on Twitter:
www.twitter.com/covestro