Effect of the Chain Alignment on the Brillouin Scattering Spectra of Hydrostatically Extruded Polypropylene.
Abstract
A detailed Brillouin scattering study of hydrostatically extruded polypropylene at room temperature is carried out. The spectra obtained in various scattering configurations are used to determine the hypersonic velocity and elastic constants of the uniaxially deformed polycrystalline polymer. As polypropylene is extruded, C(33) increases rapidly with increasing extrusion, whereas C(11) decreases slightly. This result reflects the increasing alignment of the polymer chain segment along the direction of extrusion. The elastic constant C(13) decreases slightly, but C(44) does not undergo significant change as the sample is extruded, thus indicating that the shear modulus is insensitive to the orientation of chain segments in polycrystalline polypropylene. Comparison of the Brillouin scattering results with the ultrasonic values indicate that considerable frequency dispersion in the elastic constants is present. Calculation of the orientation parameter using Mosely's theory does not yield correct results. The discrepancy indicates that Mosely's model should be used with care. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 18, 1980
- Accession Number
- ADA093223
Entities
People
- C. H. Wang
- David B. Cavanaugh
Organizations
- University of Utah