Some Applications of Vibrational Spectroscopy for the Analysis of Polymers and Polymer Composites

Abstract

Vibrational spectroscopies, including infrared and Raman techniques, are important tools for the characterization of chemical composition, molecular structures, and chain orientation under mechanical deformation of polymeric materials. The development of fiber-optic-based spectrometers has broadened the use of vibrational spectroscopy for process monitoring in various fields including polymerization, curing, and manufacturing processes. Combined with chemometrics, near-infrared (NIR) spectroscopy is now recognized as one of the most important techniques for polymer analyses. Infrared and Raman studies also offer invaluable means for the analysis of inorganic particles used as reinforcing fillers for polymers. The characterization of surface species and the nature of interfacial bonding between the organic and inorganic phases are important issues for the understanding of composite properties. Infrared spectroscopy is particularly convenient for the detection and analysis of hydroxyl groups on filler surfaces, and Raman spectroscopy is particularly well suited for the study of carbon-based materials. In both techniques, polymer-filler interactions can be evidenced through frequency shifts or width changes of bands associated with vibrational modes of functional groups of either macromolecular chains or filler particles. Selected examples of application of infrared and Raman spectroscopies illustrate their potential for monitoring polymer processes, measuring polymer orientation, and characterizing polymer composites.

Worthwhile Relevance of Infrared Spectroscopy in Characterization of Samples and Concept of Infrared Spectroscopy-Based Synchrotron Radiation

“…Linear two-dimensional infrared bond spectroscopy analysis entails the use of two-dimensional infrared bond analyses on infrared spectra [63,64]. is is done in order to increase the spectra of a disturbed sample for simpler spectral analysis and improved resolution [65,66].…”

“…e Fourier transform recognizes the impurities and generates a report on the sample composition automatically [63].…”

Infrared crystallography for framework and linker orientation in metal–organic framework films

“…1), respectively. Researchers mainly in the elds of macromolecular chemistry and structural biology have taken advantage of these sensitivity to study the degree of crystallinity and the orientation in (semi-)crystalline polymers [32][33][34] or the conformational changes in biomolecules. [35][36][37] In this context, the term infrared crystallography is commonly used, even though the method only provides information on the orientation of molecules and functional groups but not the crystal's periodicity.…”

On-Site Identification of the Material Composition of PV Modules with Mobile Spectroscopic Devices

“…Whereas the knowledge of the bill of materials is one challenge, the detection of material degradation effects-especially at the material interfaces (e.g., solar cell/encapsulant or encapsulant/backsheet)-is another important issue. Both tasks can be solved by the application of spectroscopic methods [13].…”