MALDI-TOF and 13C NMR analysis of a renewable resource additive-Thermoplastic acetylated tannins

Acetylation of mimosa flavonoid tannin is easy to occur but to proceed to completion needs the presence of a catalyst. The acetylated tannin has been shown to be composed of flavonoid oligomers of different levels of acetylation in which the robinetinidin flavonoid unit predominates. All the different -OH groups of the flavonoids, both phenolic and alcoholic, are subject to acetylation. Whatever the level of acetylation the acetylated tannin loses its solubility in water and becomes thermoplastic. In the case of the mimosa extract used here the predominance of acetylated B-flavonoid units is exclusively due to the predominance of B-type units, both robinetinidin and catechin, in the original tannin. (C) 2013 Elsevier B.V. All rights reserved.