Fig. 4 shows the formaldehyde emission testing results by the
perforator method. The formaldehyde emission was estimated
from oven dry samples and samples having 6.5% moisture content.
The value of formaldehyde emission was 9.48 and 9.82 mg/100 g
for oven dry and 6.5% M.C control MDF boards. The formaldehyde
emission value significantly decreases at Po0.005 level by the
addition of activated charcoal in UF resin. The highest decrease in
formaldehyde emission was from the AC3 sample as shown in
figure in Fig.4.
This lowering in formaldehyde emissions was caused by the
capability of the microstructure of the activated charcoal to absorb
formaldehyde in the MDF [24,25]. The activated charcoal having
chemical compound which is positively charged and polar in
nature, triggered the adsorption of the polar formaldehyde. In
addition, it is considered that might be occuring of hydrogen
bonding and Van Der Waals force curing. Due to the presence of
numerous minute pores of charcoal absorb formaldehyde molecules,
enabling charcoal to act as an absorbent [26].