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. ...

These values equal 2.0, 1.05, and 0.5, respectively, for PP, DPAcN, and PPA. It is possible that the contribution of excited states caused by n - it transitions accounts basically for a bathochromic luminescence of some PCSs and for a shift of the maxima in the luminescence spectra of polymers of this kind when proceeding from the solution to the solid phase. PCS solutions reveal concentration-quenching accom-... 

Q.-T. Pham, R. Petiaud, H. Waton, and M.-F. Llauro-Darricades, Proton and Carbon NMR Spectra of Polymers, Penton, London, 1991. 

A general purpose program has been developed for the analysis of NMR spectra of polymers. A database contains the peak assignments, stereosequence names for homopolymers or monomer sequence names for copolymers, and intensities are analyzed automatically in terms of Bernoullian or Markov statistical propagation models. A calculated spectrum is compared with the experimental spectrum until optimized probabilities, for addition of the next polymer unit, that are associated with the statistical model are produced. 

SFC-based methods still need to show their potential, in spite of past great promise. pSFC-APCI-MS is a powerful method for identification of polymer additives, provided that a library of mass spectra of polymer additives using this technique is available. SFC-MS appears less performing than originally announced nevertheless, SFE-SFC-EIMS is an interesting niche approach to additive analysis. On the other hand, we notice the lack of real breakthrough in SFE-SFC-FTIR. 

The elemental analysis, IR and lH NMR spectra of polymers VII and VIII are in agreement with the proposed chemical structure for the 1,4-polymerization of N-pheny1-3,4-dimethylenepyrrolidine. 

Is the UV-stabilization only due to the screening effect (or more precisely light absorbing effect in a spectral region where the absorption spectra of polymer and UV-stabilizer overlap) of the UV-stabilizers and/or can it be enhanced by an energy transfer from the excited polymer to the stabilizer molecule ... 

The CD spectra of polymers of a series of homologue chiral terminal acetylenes48 shows a marked dependence on the distance of the asymmetric centre from the triple bond. The relation between the two facts is however unclear, even because the UV spectrum results from the superposition of several bands, owing to the extended conjugation. 

The absorption and PL spectra of polymers 584a,b are red-shifted, compared to the analog with p-phenylene fragment 583. The effect is much more pronounced in films than in solution (films APL 495 nm for 583 and a broad structureless band at 520-650 nm for 584a,b). Single-layer (ITO/PEDOT/polymer/Ca/Ag) devices fabricated with these polymers showed moderate performance with a maximum luminance and a maximum brightness of 0.17— 0.58 cd/A and 90-150 cd/m2, respectively (Chart 2.137). 

Guide to the NMR Spectra of Polymers, Sadtler Research Laboratories, Inc., Philadelphia (1973), pp. 137-146. 

It will be obvious from my account that although I consider myself primarily a physical chemist, my concern was always with finding the most efficient solution to a problem. If that meant doing phase-rule studies with a vacuum line (hardly ever attempted before), or getting infra-red spectra of polymers to identify end-groups when the only IR instrument in the City of Manchester at that time was in the ICI laboratories at Blackley, or synthesising new model compounds or super-pure A1C13, we just overcame the practical obstacles and got on with it. 

Figure 5 Fluorescence spectra of polymers 1 (A) and 2 (B) in five different spun-cast films. (Reprinted with permission from Ref. [14]. Copyright 1998 American Chemical Society.)...

Figure 15 Laser-induced emission spectra of polymer 3 before (solid line) and after (dashed line) a one second exposure to DNT vapor.

Raman spectroscopy is a powerful tool for probing orientation, stress, and strain. Galiotis et al. have written a review on the determination of stress and strain in composites and fibers using Raman spectroscopy [179]. Young et al. discuss the complexities of correct interpretation of molecular orientation information encoded in Raman spectra of polymers [180]. Caution and a suitable number of control studies are necessary to prevent faulty conclusions. 

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