Urea–formaldehyde resin was provided by Dynea Malaysia Sdn.
Bhd. The resin has the solid content 64.4%, the F/U molar ratio was
1, pH was 8.27, and viscosity 170 CP. Mixed tropical hardwood
fibers were provided by the Robin Resources Sdn. Bhd, Malaysia.
The activated charcoal granules were procured from Hamburg
(HmbG) Chemicals. The granules were ground into very fine
powder using RetschR, ZM 200 grinder at 18,000 RPM after that
the very fine activated charcoal was a sieve out using 400 US
mesh size.