Effect of lysine-functionalized nanocellulose on urea-formaldehyde adhesive performance in particleboard production

While nanocellulose (NC) has already shown potential in enhancing urea-formaldehyde (UF)
adhesives, further studies are needed on the effects of functionalized NC on adhesive and
particleboard properties. This study evaluated the effect of unmodified and lysine-functionalized
NC on the properties of UF adhesive and particleboard performance. NC modification was
confirmed using Fourier-transform infrared spectroscopy (FTIR) and amino group quantification.
Thermogravimetric analysis (TGA) showed that functionalized NC degraded at lower
temperatures but had improved stability at higher temperatures. Differential scanning
calorimetry (DSC) indicated that NC slightly shifted the curing process to lower temperatures
and increased the curing enthalpy. NC addition increased adhesive viscosity, with loading
having a greater effect than functionalization. Unmodified NC enhanced the overall strength
of the particleboard, but did not affect water resistance or formaldehyde content. However,
functionalized NC significantly improved internal bond strength, short-term water resistance,
and reduced formaldehyde emissions. The optimal NC loading was 1%, as increasing it to
1.5% brought no further improvements. These findings suggest that functionalized NC can be
an effective additive for enhancing UF adhesive performance in particleboard applications.