Vibrational spectra of polymers

Figure 6 Vibrational spectra of polymers, (a) Transmission infrared spectrum of polyethylene (b) electron-induced loss spectrum of polyethylene (c) transmission infrared spectrum of polypropylene. ...

Raman is simple to use and require virtually no sample preparation. The vibrational spectra of polymer samples in their original forms can be measured and casting or hotpressing of the material into thin films (commonly used for FTIR measurements), a very time-consuming procedure that can affect the original structure of the material, are not required. It also offers remote analysis capabilities if combined with fibre optics [108, 109]. Accurate determination of contaminant content in recycled polymeric resins have been reported in the literature [110, 111, 112]. 

IR and Raman spectra are particularly sensitive to the configurations and conformations of the polymer molecules. The variations in the conformational and configurational structures are reflected in specific observable frequencies. Consequently, it is possible to detect and quantify the amounts of the conformational isomers whether they be crystalline, liquid crystalline, or disordered (amorphous). The vibrational spectroscopic approach to structural elucidation in polymers relies on the comparison of vibrational spectra of polymers containing specific conformational structures (incorporated into the polymer during polymerisation or by thermal or chemical modification), with spectra of models (polymers and small molecules) containing similar structures presumed to be present in the polymers. 

Spectroscopic studies at variable temperatures have become an important tool for the characterization of the physical structure of polymers. Especially in combination with thermoanalytical DTA or DSC measurements short-time spectroscopic FTIR investigations in controlled heating or cooling experiments provide a detailed picture of the structural changes as a function of temperature. Any variations of spectroscopic parameters such as intensity, wavenumber position and band shape directly reflect the temperature dependence of the vibrational behaviour of the investigated polymer as a consequence of changes in the inter- and intramolecular interactions and the state of order The vibrational spectra of polymers recorded in selected... 

We have just outlined the way theoreticians in polymer dynamics face the problem of the understanding of the vibrational spectra of polymers in their realistic state. The reader interested in the theoretical aspects will find in the references quoted all indications which will enable him or her to grasp the theory and to carry out the calculations. 

The second part contains the theoretical calculation of different properties of polymers based on the methods systematically introduced in the first part. The properties calculated include the electronic and vibrational spectra of polymers, and the computation of their transport, magnetic, and mechanical properties. In cases where reliable experimental data are available, the theoretical results are compared with them. 

Vibrational spectra of polymer chains. Nippon Kagaku Zasshi 88, 111—124 (1967). 

The present review involves the main results concerning the FIR spectra of polymers obtained mainly during the last 10-15 years. In this paper, we point out the usefulness of studying the low-frequency vibrational spectra of polymers. Although we present almost entirely the FIR data, it should be noted that Raman spectroscopy is the necessary complementary method in some cases. 

Neppel A, Butler IS, Eisenberg A (1979) Vibrational spectra of polymers. 2. Variable-temperature raman spectroscopy as a probe for ion clustering in ionomers. Macromolecules 12 948-952... 

Neutron scattering and vibrational spectra of polymer chains and crystals. Kept, of Japan Atomic Energy Kesearch Inst, (to be published 1968). 

Hydrogen and deuterium composition profile Vibrational spectra of polymer surface adjacent to ATR-crystal surface Vibrational spectra of thin films and absorbed layers... 

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