Certain commercial equipment is identified in this article to adequately specify the experimental procedure. In no case does such identification imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the items identified are necessarily the best available for the purpose.
Characterization of the skin orientation of thermotropic liquid-crystalline copolyester moldings with near-edge X-ray absorption fine structure†
Article first published online: 29 SEP 2005
Copyright © 2005 Wiley Periodicals, Inc.
Journal of Applied Polymer Science
Volume 98, Issue 6, pages 2473–2480, 15 December 2005
How to Cite
Bubeck, R. A., Thomas, L. S., Rendon, S., Burghardt, W. R., Hexemer, A. and Fischer, D. A. (2005), Characterization of the skin orientation of thermotropic liquid-crystalline copolyester moldings with near-edge X-ray absorption fine structure. J. Appl. Polym. Sci., 98: 2473–2480. doi: 10.1002/app.22448
- Issue published online: 29 SEP 2005
- Article first published online: 29 SEP 2005
- Manuscript Accepted: 21 MAR 2005
- Manuscript Received: 8 NOV 2004
- National Science Foundation. Grant Numbers: DMI-0132519, DMR-9304725
- State of Illinois (through the Department of Commerce and the Board of Higher Education). Grant Number: IBHE HECA NWU 96
- U.S. Department of Energy (Basic Energy Sciences, Office of Energy Research). Grant Number: W-31-102-Eng-38
- E. I. DuPont de Nemours & Co.
- The Dow Chemical Co.
- injection molding;
- liquid-crystalline polymers (LCP);
The process of injection-molding net-shape parts from thermotropic liquid-crystalline polymers results in a skin-core macrostructure. The underlying orientation in the core and the skin may differ both in magnitude and direction. A combination of near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and two-dimensional wide-angle X-ray scattering (2D WAXS) in transmission was used to characterize the orientation in injection-molded plaques fabricated from thermotropic liquid-crystalline copolyesters based on either 4,4′-dihydroxy-α-methylstilbene or 6-hydroxy-2-naphthoic acid/6-hydroxybenzoic acid. NEXAFS is presented as a noninvasive in situ means of determining surface layer orientation that samples to a depth of as little as 2 nm and does not require slicing or ultramicrotoming of the samples. The effects of various processing conditions on the surface orientation in the region of the centerline of square injection-molded plaques are presented and discussed. Comparisons are made between orientation parameters obtained by 2D WAXS in transmission, which is dominated by the microstructure in the core, and the NEXAFS technique. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2473–2480, 2005