Root-inspired grafting of wood surfaces with hyperbranched polymers for enhanced interfacial adhesion with impregnated decorative paper

Abstract

A root-like waterborne hyperbranched polymer, synthesized from diethylenetriamine (DETA) and methyl acrylate (MA) monomers, was inspired by the effect of solidifying soil with tree roots. This polymer was then blended with aqueous isocyanate SK615, known as MD-HBP-NH₂, to serve as a surface modifier for blockboards. The blockboards were treated with a modifier to enhance the interfacial adhesion with melamine-formaldehyde (MF) resin-impregnated decorative paper, thereby preventing surface cracks. The polycondensation reaction temperatures of the modifiers were compared. These results indicated that a hyperbranched root-structured polymer emulsion was formed through Michael addition reactions. Following this modification, the blockboards demonstrated enhanced planeness and dimensional stability. Furthermore, the isocyanate groups reacted with the exposed hydroxyl groups, and the amino groups reacted with the aldehyde groups in the MF resin, thereby enhancing the interfacial bonding strength between the wood and the impregnated decorative paper. At a polycondensation temperature of 155 °C, optimal overall performance was attained, with the ability to penetrate the wood surface to a depth of 1.28 mm, and exhibited superior surface crack resistance. Moreover, this waterborne hyperbranched polymer modifier is eco-friendly, green, and non-toxic, with lower levels of volatile organic compounds. This presents a promising avenue for the development of eco-friendly modifiers to prevent surface cracking in wood-based panels with impregnated decorative paper.