Characterization of Algerian Eucalyptus tannins for a potential use in resin and foam formulation

Abstract

Increasingly high demand for composite materials is being recorded, creating a dilemma, especially for researchers. For some time now, a lot of work has been done on bio-sourced resins, derived from local plants such as eucalyptus in order to replace synthetic resins in the production of composites. Recently, there has been a growing interest in tannin resins for their low cost and also for their availability. Tannins are natural phenolic compounds, which have been extensively researched for the development of a wide range of industrial applications. First, the Algerian Eucalyptus tannins have been extracted by varying different extraction times, extraction temperature, solvent concentration, stage extraction and liquid-solid ratio. The the phenolic composition of Algerian Eucalyptus barks was studied. FTIR (Fourier Transformed Infrared Spectroscopy), NMR (Nuclear Magnetic Resonance) and TGA/DSC ( Thermogravimetric analysis were used to examine Eucalyptus tannins. Analyzes showed that Eucalyptus barks are rich in condensed tannins, especially in procyanidin and prodelphinidin tannins. The reactivity to formaldehyde test (Stiasny number) showed the possible use of Eucalyptus tannins in resine and foam formulation.