About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
Polymer
Paper
Molecular dynamics of a crystal-crystal phase transition in an alternating copolymer of ethylene and chlorotrifluoroethylene using the Raman active longitudinal acoustical mode (LAM)
Abstract
A low frequency Raman band assignable to the longitudinal acoustical mode (LAM) in an alternating copolymer of ethylene and chlorotrifluoroethylene (E/CTFE) has been observed. The anisotropic scattering properties of an oriented filament have been determined by polarized Raman measurements and the results confirm this assignment. The frequency-chain length variation characteristic of the LAM has also been observed and studied through carefully-controlled annealing experiments. The dynamics of the 150°C crystal-crystal phase transition was investigated using the bandwidth and frequency position of the LAM as a molecular probe. It was found that its shift to lower frequency upon crossing the phase boundary reflected a decrease in the c-axis Young's modulus consistent with a deviation of the backbone conformation away from a planar structure. © 1981.