Crystallinity of Low Molar Ratio Urea-Formaldehyde Resins Modified with Cellulose Nanomaterials

Inherent crystalline domains present in low formaldehyde to urea (F/U) molar ratio urea-formaldehyde (UF) resins are responsible for their poor adhesion wood-based composite panels. To modify the crystallinity of (LMR) UF resins, this study investigates additional effect cellulose nanomaterials (CNMs), such as microfibrils (CMFs), nanofibrils (CNFs), and TEMPO-oxidized CNFs (TEMPO-CNFs) on modified LMR resins. First, two modification methods (post-mixing situ) were compared with TEMPO-CNFs. The TEMPO-CNFs decreased nonvolatile solid contents, while increasing viscosity gel time. However, situ showed lower than that post-mixing. Then, method was all CNMs CMFs using increased contents but lowest even though not significantly changed These results suggest these should be prevent formation