Supplementation of Natural Tannins as an Alternative to Formaldehyde in Urea and Melamine Formaldehyde Resins used in MDF Production

Sima Sepahvand, Kazem Doosthosseini, Hamidreza Pirayesh, Behrooz Karamdoost Maryan
2018 Drvna industrija  
The aim of this study was to evaluate some mechanical and physical properties of medium density fi berboards (MDF) made from different adhesive types. Five panel types were made from mixtures of tannin (T) to urea formaldehyde (UF) and tannin to melamine formaldehyde (MF), TUF 10% , TUF 20% , MF, TMF 10% and TMF 20% , respectively. Besides, the effect of press temperatures (170 and 180 °C) on the curing of the formulations was studied. Some mechanical properties (modulus of rupture, modulus of
more » ... lasticity and internal bond strength), physical properties (thickness swelling and water absorption) and formaldehyde emission of the resulting panels were determined. The incorporation of tannin decreases the formaldehyde emission of the panels. However, fl exural properties and internal bond strength decreased with increasing tannin ratio. The results indicated that panels can be manufactured using tannin up to 10 % in UF resin without falling below the minimum EN Standard requirements of mechanical properties for general purpose MDF panels. SAŽETAK • Cilj rada bio je procijeniti određena mehanička i fi zikalna svojstva ploča vlaknatica srednje gustoće (MDF ploča) proizvedenih primjenom različitih vrsta ljepila. Pet vrsta ploča proizvedeno je uz primjenu smjese tanina (T) i urea-formaldehidne smole (UF) te tanina i melamin-formaldehidne smole (MF) u različitim omjerima, označenih kao TUF10%, TUF20%, MF, TMF10% i TMF20%. Osim toga, proučavan je utjecaj temperature prešanja (170 i 180 °C) na otvrdnjavanje tako dobivenih smjesa ljepila. Upoznata su i neka mehanička svojstva
doi:10.5552/drind.2018.1726 fatcat:swkumj5ndvbwbkv4cee4oshpyq