The activation energy (Ea) of the curing reaction of resins is
estimated from the slope of plot between ½−lnðβ=T2p
Þ and½100=Tp
given in Table 2. Whereas the values of R2 that show the quality
of the fitting curve. The Ea of the curing reaction decreased with
activated charcoal concentration as shown in Table 3. There
are several reasons for the decrease in activation energy as:
(i) the interaction of carbonyl group present in the activated
charcoal and possibly formed to coordinate covalent bond with
UF polymer chain or a catalytic activation of the resin selfcondensation
induced by the charcoal derived from wood constituents,
(ii) the mass of combined secondary forces those are
binding the molecules of oligomer to the surface of charcoal or
lignocellulosic substrate is very high leading to the pronounced
weakning of the bonds most susceptible to cleavage in the
adhesive molecules, these bonds need to be cleaved for the
polymerization and hardening of the resin [19]. Thus in this
manner activated charcoal accelerating adhesive curing, (iii)
possibly on the charcoal separate some of the water from the
resin by absorption and induces a higher resin concentration and
thus a faster reaction.