Morphological Characterization of High-Pressure Crystallized Polyethylene by Raman and Brillouin Scattering

The low-frequency Raman-active longitudinal acoustical mode (LAM) has been observed in high-pressure crystallized polyethylene (HPCPE), which exhibits an extended-chain morphology. Through the use of a multipass Fabry-Perot interferometer a band at 0.5 cm-1 has been observed in the low-frequency spectral region and tentatively assigned to LAM. After melting and recrystallization this band shifted to 12.8 cm-1 and was then observed with standard Raman instrumentation, with its position reflecting a significant reduction in lamellar thickness. © 1983, American Chemical Society. All rights reserved.