MALDI-ToF Analysis of Tannin-Resorcinol Resins by Alternative Aldehydes: Glyoxal and Glutaraldehyde
Résumé
Glyoxal and glutaraldehyde are two viable alternatives to formaldehyde for the preparation of tannin-resorcinol-aldehyde adhesive but lead to less resistant glue joint. Tannin-resorcinol-glyoxal (TRG1) and tannin-resorcinol-glutaraldehyde (TRG2) resins have been prepared and analyzed by matrix-assisted laser desorption/ionization time of flight (MALDI-ToF) spectrometry to understand the chemical process behind the pre-curing of these resins and possibly the causes of this lower resistance. The analysis showed that TRG resins are not a simple mix of resorcinol-aldehydes oligomers and flavonoids, but a much more complex combination of various species including tannin-aldehydes and tannin-resorcinol oligomers.