Properties of Tannin-Glyoxal Resins Prepared from Lyophilized and Condensed Tannin

Abstract

The main focus of this study was to prepare a thermoset adhesive using green way from two bio-product derivatives i.e., namely: condensed tannin (CT) and lyophilized tannin (LT) from grape pomace, which acquired from wine industries. Firstly, the obtained tannins were isolated and characterized especially by their thermal properties of the isolated tannin fractions which have been investigated in detail. Then, two adhesive resins were prepared using the isolated tannins with the glyoxal as cross-linking agents were employed to produce tannin-glyoxal resin. The evolution of the viscosity during the curing process of Resin-Tannin-Lyophilize-Glyoxal (RTLG) and Resin-Tannin-Condensed-Glyoxal (RTCG) was studied. The influence of the main gelation conditions such as temperature, pH and curing agent type on the gelation time was studied and discussed.