Raman investigation of tannin foams

Full text: Tannin-based organic foams are new foam materials which are environmentally friendly, resistant to re and inexpensive, and intended to be used for building insulation, and also as water absorber or shock absorber. These foams can be produced via an acid catalyzed polycondensation reaction between condensed flavonoids and furfuryl alcohol. Several studies deal with the mechanism involved in this process, but some ambiguities still persist. Raman spectroscopy is an analytical technique suitable for the non-destructive chemical investigation of polymers, allowing to determine the presence of functional groups within a polymer through the interaction of laser light with the vibrational modes of the molecules setting up the sample under investigation. By this spectroscopic technique we have characterized the tannin-based foams and compared their spectral signature with that of tannins, and of polymerized furfuryl alcohol. Similarities and differences to the spectral features of carbonaceous material are discussed. (author)