This can be ascribed to the presence of kenaf bast
particles in the Type 7 panels. In a previous study [22], kenaf bast
was reported to be having low wettability. This could have contributed
to the low water absorption of the Type 7 panels. However,
swelling and water absorption of the sample were relatively high
in Type 8 panels, which can be due to the massive amount of KC
employed in manufacturing the board owing to the low density
of KC. Accordingly, when the samples were submerged in water,
low-density wood and a high absorbant material such as KC might
have increased the TS and WU of the boards since kenaf required
large volume of particles to equate the mass and achieve the targeted
board density [21,23]. Furthermore, once immersed in water,
the UF resin, which is designed for interior applications, is not
durable under outdoor exposure conditions.