Application of Myrcia splendens tannins in the composition of urea-formaldehyde adhesive for sustainable wood bonding

Abstract

Tannins from Myrcia splendens from the Amazon rainforest were used for the first time in the formulation of a urea-tannin-formaldehyde (UTF) resin. The objective was to evaluate the effect of different tannin proportions on the glue line performance in Pinus sp. woods, glued with UTF adhesive. The tannins were extracted in a water bath, using 1500 mL of water and 100g of dry bark (liquor/bark 15:1), with addition of 3% Na2SO3, at a temperature of 70 °C for three hours. The adhesives formulations were based on the gradual replacement of mass of the urea-formaldehyde (UF) adhesive by tannin powder, totalizing four compositions and one control treatment. UTF adhesives were evaluated for their physicochemical properties, shear bond strength (wet and dry) and wood failure. The addition of M. splendens tannins to the urea formaldehyde adhesive promoted an increase in glue line strength. The proportion of 5.0% of tannins proved to be ideal in the formulation of the UTF adhesive, considering all the parameters evaluated. Thus, this study proves the potential use of Amazonian tannins from Myrcia splendens in the partial composition of more sustainable UTF adhesives.

Recent progress of biomass in conventional wood adhesives: a review

“…This modification enables the production of wood-based products, like plywood, particleboard, and fiberboard, that exhibit reduced formaldehyde emissions. 34–36 Usually, tannins are regarded as an additional ingredient that can be blended in varying ratios with typical UF resins. 35,36 Thus, bonding products with tannin–UF resins achieved through blending modification exhibit lower levels of formaldehyde emissions compared with those bonded using traditional UF resins.…”

“…34–36 Usually, tannins are regarded as an additional ingredient that can be blended in varying ratios with typical UF resins. 35,36 Thus, bonding products with tannin–UF resins achieved through blending modification exhibit lower levels of formaldehyde emissions compared with those bonded using traditional UF resins. Peng et al 37 unveiled an innovative approach for overcoming the constraints of inadequate water resistance and elevated formaldehyde emission from UF resins by partially replacing urea with tannin (Fig.…”

Enhancing Environmentally Friendly Tannin Adhesive for Plywood through Hyperbranched Polyamide

“…To address these challenges and explore more effective formulations, tannin has been incorporated as an additive into urea-formaldehyde resin (UF) or phenol-formaldehyde resin (PF) to either cross-link the UF prepolymers − or serve as alternatives to costly petrochemicals. , Although tannin additives demonstrate benefits such as reduced formaldehyde emissions, enhanced bonding strength, and improved water resistance, these strategies still face limitations concerning environmental sustainability, performance, and utilization efficiency …”