The characteristics of polymers are largely controlled by microscopic mobility-torsional-vibrational and extreme-amplitude motion of atomic groups of macromolecules, that manifests itself in the form of λ, γ, β-entertainment transitions at temperatures beneath Tc and α-glass change at Tc. The stepwise "defrosting" of molecular motion is directly mirrored in the temperature changes in the characteristics of polymers. Despite a large number of studies of transitions, their common molecular devices remained unexplained just before recently. A succession of experimental works acted by the procedures of low-frequency Far-shade resembling such a color and Raman spectroscopy and generalizations made with the use of written data also fashioned it possible to resolve named task. The starting points for the microscopic interpretation of changes were estimates of potential barriers and units of motion, their corresponding with the traits of molecules and parameters of entertainment transitions. The experiments were completed activity in the spectral range 8-420 cm-1 (∼ 0.24-12.5 THz), including at hotness variation from 85 to 400K, on a expansive range of organic linear and cross-connected polymers, as well as oligomers and depressed molecular weight meanings. All the results presented in this place work show that low-frequency Infrared and Raman spectroscopy admits clarifying microscopic mechanisms of the relaxation changes in amorphous polymers and corroborating the relations of these processes with microscopic characteristics of polymers, to a degree the structure of a monomer unit, the union energy, the potential hurdle to internal rotation and thermodynamic chain stubbornness.
Author(s) Details:
V. A. Ryzhov,
Ioffe
Physicotechnical Institute, Russian Academy of Sciences, Politekhnicheskaya ul.
26, St-Petersburg-194021, Russia.
Please see the link here: https://stm.bookpi.org/NFPSR-V7/article/view/9424
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