MALDI-TOF, 13C NMR and FT-MIR analysis and strength characterization of glycidyl ether tannin epoxy resins

The chemical modification of tannin through epoxidation is a way to develop new applications for tannins and to improve tannin resins performances. In this paper the influence of reaction conditions was studied. Commercial tannin bark extract was epoxidized. The resulting products were characterized by FT-IR Spectroscopy, C-13 NMR and MALDI-TOF mass spectrometry. Tannin epoxidation has been confirmed by C-13 NMR and FT-MIR. Wood specimens were bonded with mixed diglycidyl ether of bisphenol A (DGEBA) and glycidyl ether tannin (GET) epoxy resin formulations. The bonded joints were tested for block shear strength. The results obtained indicated that such formulations, based on up to 75% commercial natural materials are capable of satisfying the shear strength requirements of relevant international standards. (c) 2015 Elsevier B.V. All rights reserved.