Abstract:
This research examines the effect of filler materials on urea formaldehyde (UF) adhesives
used in the wood composite manufacturing industry. The study compares the
performance of wheat flour, a commonlyused but expensivefiller, with coal fly ash and
wood fly ash, waste productswith adverse environmental impacts. The objectives include
evaluating the impact of coal fly ash and wood fly ash fillers on adhesive viscosity and
the mechanical properties (bending strength and modulus of elasticity) of wood
composites and comparing the results with wheat flour. Viscosity measurements
conducted with a Brookfield viscosity meter indicate a significant increase in UF adhesive
viscosity over time with the addition of wheat flour. Wood fly ash shows minimal impact
on viscosity, while coal fly ash contributes moderately compared to wheat flour and wood
fly ash. Bending tests (ASTM D790) and empirical equations, following EN-325 sampling
standards, are employed to assess the effect of filler materials and concentration on
bending strength and modulusof elasticity in the final wood composites. Plywood bonded
with coal fly ash demonstrates the highest bending strength and modulus of elasticity,
with wheat flour as the reference filler. Both wheat flour and coal fly ash exhibit improved
bending strength with increasing filler concentration, whilewood fly ash exhibits the
opposite effect. In conclusion, coal fly ash proves to be a suitable substitute for wheat
flour as a filler in urea formaldehyde adhesives, providing satisfactory adhesive properties
and enhancing the performance of wood composites.
