Bulletin of the American Physical Society
2009 APS March Meeting
Volume 54, Number 1
Monday–Friday, March 16–20, 2009; Pittsburgh, Pennsylvania
Session Y16: Elastomers and Gels II
8:00 AM–11:00 AM,
Friday, March 20, 2009
Sponsoring Unit: DPOLY
Chair: Ryan Hayward, University of Massachusetts
Abstract ID: BAPS.2009.MAR.Y16.6
Abstract: Y16.00006 : Dynamics of Segmented Polyurethane Elastomers Using Dielectric Spectroscopy*
9:00 AM–9:12 AM
Preview Abstract Abstract
(The Pennsylvania State University)
This investigation focuses on the molecular dynamics of segmented polyurethane copolymers with different hard segment contents (30 to 52 wt percent) and soft segment chemistries. Methylene bis(p-phenyl isocyanate) and 1,4-butanediol constitute the hard segments in all materials under investigation, while soft segments include poly(tetramethylene oxide) and a 80-20 mixture of poly(dimethylsiloxane) and poly(hexamethylene oxide). The dynamics of these materials were explored over a wide temperature and frequency range using dielectric spectroscopy. In addition to investigating the details of segmental and local processes, three dielectric relaxations above Tg were observed for the first time in segmented polyurethanes, and their origin discussed in the presentation. For example, the highest temperature process is assigned to Maxwell-Wagner-Sillars interfacial polarization. The strength of the MWS process is a sensitive indicator of the change in microphase-separated character. It disappears at a temperature similar to that at which the small-angle X-ray scattering maximum disappears, indicating the transformation to the single phase state.
*Supported by the NSF Polymers Program, DMR-0605627.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2009.MAR.Y16.6
The American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics.
1 Physics Ellipse, College Park, MD 20740-3844
Editorial Office 1 Research Road, Ridge, NY 11961-2701 (631) 591-4000
Office of Public Affairs 529 14th St NW, Suite 1050, Washington, D.C. 20045-2001 (202) 662-8700