A novel design for nanocellulose reinforced urea–formaldehyde resin: a breakthrough in amino resin synthesis and biocomposite manufacturing

Urea–formaldehyde (UF) resins are often reinforced with natural fibers or nanostructures such as cellulose microfibrils (CMFs) to improve their mechanical and physical properties in wood panels. However, the high-water content in these suspensions is a limitation on applications in thermosetting resins. The innovative technology investigated here consists of the in-situ production of a methanediol-based suspension of CMFs through a mechanical process and its incorporation during resin synthesis. We sought to maintain the physicochemical properties and the basic chemical composition of the resin. The synergy between the resin and CMFs provided a shielding effect and a greater storage modulus (E’). We demonstrate that this approach is robust through standard viscoelastic, physical, and mechanical tests. Likewise, a methanediol-based CMF suspension used to synthesize UF resin was effective to reduce formaldehyde emission during the resin cure reactions. Finally, the bio-based composites manufactured with this UF resin containing CMF had better performance due to increased internal bond strength by up to 15%, reduced water absorption by up to 8%, and reduced formaldehyde emission by 30% at environmental temperature.