For Immediate Release

Medical-grade polycarbonate exhibits excellent retention of mechanical properties after gamma irradiation

Testing indicates medical copolyester displayed greater relative changes in viscosity than polycarbonates

 Pittsburgh, May 5, 2011 — Consistent resin performance and the retention of physical and mechanical properties over a wide range of conditions are critical to plastic medical devices. Bayer MaterialScience LLC scientists have studied newly introduced medical grades of its Makrolon® polycarbonate resin to demonstrate how these grades maintain stiffness, toughness and other key properties after gamma sterilization.

The results of the studies are detailed in a technical paper: Property Retention of High-Flow Medical Resins After Gamma Irradiation, authored by Pierre Moulinie and John J. Charles, scientists with Bayer MaterialScience LLC. Dr. Moulinie presented the paper’s findings during the Society of Plastics Engineers’ ANTEC 2011 annual technical conference and exhibition, held recently in Boston.

In these studies, the outstanding property retention of Makrolon Rx2435 polycarbonate after gamma irradiation up to 60 kGy is highlighted. In addition to higher flow than other radiation-stabilized Makrolon grades and a competitive copolyester, Makrolon Rx2435 showed excellent retention of rigidity and ductility after gamma sterilization. The presentation also discusses color shifts which occur after gamma sterilization and points out the dangers of assuming that the lack of color shift correlates to property retention. A competitive copolyester showed greater molecular weight loss and change in chemical resistance than Makrolon polycarbonate after gamma sterilization.

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 14,400 employees at 30 production sites around the world and 2010 sales of 10.2 billion euros. 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.
Bill Allan, Phone: 412-777-5200

For more information about Bayer MaterialScience LLC or for a copy of this technical paper, call 1-800-662-2927, email or visit
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Media Contact(s)
Name:    Bill Allan, Phone
Phone:    412-777-5200
Company:    Bayer MaterialScience