Abstract
In the reported experiments, Brillouin measurements of sound velocity and attenuation as a function of propagation direction in oriented PMMA have been used to determine the anisotropy of the elastic properties at hypersonic frequency. The formation of voids is believed to play an important role; these voids occur in material that is densified by up to 15% at the highest draw ratios studied. The presence of extra components in the Brillouin spectra may result from scattering off phonons in the voids, in which case a void density of 0. 3 cm** minus **3 is deduced. Measurements of sound velocity and attenuation as function of sound wavelength show dispersion, indicating that the structure has approximate linear dimensions of 1. 5 mu , and that it is asymmetric with the longer dimension perpendicular to the draw direction. Measurements of the Landau-Placzek ratio support this model, but electron micrographs are inconclusive.
| Original language | English (US) |
|---|---|
| Title of host publication | J Polym Sci Polym Symp |
| Place of Publication | New York, NY |
| Publisher | John Wiley |
| Pages | 85-96 |
| Number of pages | 12 |
| Edition | 58 |
| State | Published - 1977 |
| Externally published | Yes |
| Event | Orientat Eff in Solid Polym, Proc of the Europhys Conf on Macromol Phys, 5th - Budapest, Hung Duration: Apr 27 1976 → Apr 30 1976 |
Other
| Other | Orientat Eff in Solid Polym, Proc of the Europhys Conf on Macromol Phys, 5th |
|---|---|
| City | Budapest, Hung |
| Period | 4/27/76 → 4/30/76 |
ASJC Scopus subject areas
- General Engineering