Introducing Flexibility in Urea-Formaldehyde Resins: Copolymerization with Polyetheramines

Abstract

Adhesives obtained by copolymerizing urea, formaldehyde, and difunctional polyetheramine with different molecular weights (230, 600, 900, and 2000 gmol(-1)) are presented as a more resilient alternative to conventional urea-formaldehyde resins. Urea and polyetheramine contents were varied and the resulting resins characterized by FTIR, C-13-NMR, and TGA. These resins were used for production of agglomerated cork panels, an application that demands that the binder system is flexible. Polyetheramine with molecular weight 900 g mol(-1) yielded the most promising agglomerated cork panel, with remarkable flexibility, good tensile strength, and with the E1 formaldehyde content specification for wood-based panels used in construction, according to European Standard EN 12460-5. These new thermoset adhesives have demonstrated to be capable of being used in systems where conventional formaldehyde-based resins do not perform well due to inherent high rigidity. (C) 2018 Wiley Periodicals, Inc.