Stuart Lindsay, I. W. Shepherd

Research output: Chapter in Book/Report/Conference proceedingChapter

6 Scopus citations


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 languageEnglish (US)
Title of host publicationJ Polym Sci Polym Symp
Place of PublicationNew York, NY
PublisherJohn Wiley
Number of pages12
StatePublished - 1977
Externally publishedYes
EventOrientat Eff in Solid Polym, Proc of the Europhys Conf on Macromol Phys, 5th - Budapest, Hung
Duration: Apr 27 1976Apr 30 1976


OtherOrientat Eff in Solid Polym, Proc of the Europhys Conf on Macromol Phys, 5th
CityBudapest, Hung

ASJC Scopus subject areas

  • General Engineering


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