Raman spectroscopic investigation of tannin-furanic rigid foams

Tannin-furanic rigid foams are innovative polymeric materials made of inexpensive organic ingredients, and are usually produced via an acid catalyzed polycondensation reaction between furfuryl alcohol and condensed flavonoids (e.g. Mimosa tannin). These bio-friendly foams have already been proposed e.g. as insulating material for eco-sustainable buildings (green building technology), as their most important physical properties are their low thermal conductivity and their high fire resistance. The aim of the present study is the Raman spectroscopic characterization of the tannin-furanic rigid foams in order to establish a tool complementary to infrared spectroscopy for comparing their spectral signature with that of the precursor materials furfuryl alcohol, polymerized furfuryl alcohol, and Mimosa tannin. The discussion deals with similarities and differences to the spectral signatures of sp(2) carbon based materials, the still preserved organic nature of the tannin-furanic foam, and with similarities and differences to recently reported infrared spectra. (C) 2016 Elsevier B.V. All rights reserved.