Condensed tannins extraction from grape pomace: Characterization and utilization as wood adhesives for wood particleboard

The extraction of condensed tannins from grape pomace was examined using water medium in the presence of NaOH, Na2CO3, NaHCO3 eventually in the presence of Na2SO3. The tannin fractions reactivity towards formaldehyde was studied by gel time analysis and thermomechanical analysis in bending and it was demonstrated that despite of their lower phenolic contents, some of these extracts displayed promising properties for adhesive applications. A resin formulation in which the total content of tannin is 75% of the total resin solids content gave good results and was employed for the elaboration of the first grape pomace based-wood particleboard which passed relevant international standard specifications for interior-grade panels.

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► Condensed tannins were extracted from grape pomace in water medium.
► The tannin fractions reactivity towards formaldehyde was studied.
► The first grape pomace based-wood particleboards were prepared.