Spectroscopy of polymers

In terms of characterizing the microstrac-ture of polymer chains, the two most useful techniques are infrared spectroscopy (IR) and nuclear magnetic resonance (NMR) spectroscopy. Commercial infrared spectrometers were introduced after the end of the second world war and quickly became the workhorse of all polymer synthesis laboratories, providing a routine tool for identification and, to a certain degree, the characterization of microstructure (e.g., the detection of short chain branches in polyethylene). In this regard it can no longer compete with the level of detail provided by modem NMR methods. Nevertheless, IR remains useful or more convenient for certain analytical tasks (and a powerful tool for studying other types of problems). So here we will first describe both techniques and then move on to consider how they can be applied to specific problems in the determination of microstructure. 

This isn t the only way to do the experiment If you could find a source that emitted light at a specific frequency and if this frequency could be changed or tuned across a broad range, then you wouldn t need a dispersive element like a prism (or gratings, or an interferometer) at all. This is essentially how NMR works in older instruments. A 

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Feldman K, Tervoort T, Smith P and Spencer N D 1998 Toward a force spectroscopy of polymer surfaces Langmuir 14 372... 

More recently, Raman spectroscopy has been used to investigate the vibrational spectroscopy of polymer Hquid crystals (46) (see Liquid crystalline materials), the kinetics of polymerization (47) (see Kinetic measurements), synthetic polymers and mbbers (48), and stress and strain in fibers and composites (49) (see Composite materials). The relationship between Raman spectra and the stmcture of conjugated and conducting polymers has been reviewed (50,51). In addition, a general review of ft-Raman studies of polymers has been pubUshed (52). 

H. W. Seisler and K. HoUand-Morit2, Infra Red and Raman Spectroscopy of Polymers Marcel Dekker, Inc., New York, 1980. 

M. W. AT2rs1, Attenuated Total Reflectance Spectroscopy of Polymers Theory and Practice, American Chemical Society, Washington, D.C., 1996. 

Janshoff, A., Neitzerl, M., Oberdorfer, Y. and Fuchs, H., Force spectroscopy of molecular systems - single molecule spectroscopy of polymers and biomolecules. Angew. Chem. Int. Edn., 39(18), 3213-3237 (2000). 

See, e.g., K. Seki, Photoclecrron spectroscopy of polymers, in Optical Techniques to Characterize Polymer Systems (Ed. H. Bassler), Elsevier, Amsterdam 1989, Chapter 4. 

Hatada, K. NMR Spectroscopy of Polymers-, Springer-Verlag Berlin, 2003. 

Koenig, J. L. Fourier Transforms Infrared Spectroscopy of Polymers, Vol. 54, pp. 87-154. 

FIGURE 26 Fourier transform infrared spectroscopy of polymer samples prepared at either 130, 145, or 160°C with or without cyclo-benzaprine hydrochloride (CBP). Polymer prepared from 3,9-bis-(ethylidene-2,4,8,10-tetraoxaspiro[5,5)undecane) and a 25 75 mole ratio of trans-cyclohexane dimethanol and 1,6-hexanediol and contained 3 wt% phthalic anhydride and 7.5 wt% cyclobenzaprine hydrochloride (CBP). 

M.W. Urban and T. Provder, Multidimensional Spectroscopy of Polymers. Vibrational, NMR, and Fluorescence Techniques ACS Symposium Series No. 598, American Chemical Society, Washington, 1X7 (1995). 

N.J. Everall, J.M. Chalmers and P.R. Griffiths (Eds.), Vibrational Spectroscopy of Polymers Principles and Practice, Wiley, Chichester, 2007. 

J.L. Koenig, Spectroscopy of Polymers, 2nd ed., Elsevier Science, New York, 1999. 

J.M. Chalmers and N.J. Everall, Qualitative and quantitative analysis of plastics, polymers and rubbers by vibrational spectroscopy. In N.J. Everall, J.M. Chalmers and P.R. Griffiths (Eds.), Vibrational Spectroscopy of Polymers Principles and Practice, Wiley, Chichester, 2007, pp. 1-67. 

M. Claybourn, Infrared Spectroscopy of Polymers Analysis of Films, Surfaces and Interfaces, Global Press, Chicago, 1998. 

As already indicated above, what one may consider a surface depends on the property under consideration. Adhesion is very much an outer atomic layer issue, unless one is dealing with materials like fibreboard in which the polymer resin may also be involved in mechanical anchoring onto the wood particles. Gloss and other optical properties are related to the penetration depth of optical radiation. The latter depends on the optical properties of the material, but in general involves more than a few micrometer thickness and therewith much more than the outer atomic layers only. It is thus the penetration depth of the probing technique that needs to be suitably selected with respect to the surface problem under investigation. Examples selected for various depths (< 10 nm, 10 s of nm, 100 nm, micrometer scale) have been presented in Chapter 10 of the book by Garton on Infrared Spectroscopy of Polymer Blends, Composites and Surfaces... 

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