3.2. Evaluation on mechanical properties
Figs. 1 and 2 display mechanical properties of the samples. The
highest MOE and MOR values of 863.93 MPa and 7.09 MPa were
found for the samples manufactured from the particles boiled in
hot water, respectively. Samples made with NaOH treated
particles had the lowest MOE and MOR values of 839.66 MPa
and 5.23 MPa, respectively. Similar findings from previous study
carried out by Norul Izani et al. [10] reported that NaOH reduced
the strength properties of MOE and MOR of board manufactured
from soaking empty fruit bunch fibers with 12% and 15%
reduction, respectively. Hot water treated samples had enhanced
bending properties compared to those of control samples. The
increments of improvement of MOE and MOR values of hot water
treated samples were 0.52% and 20.37% higher than those of
control samples, respectively. These results were expected with
considering the previous study of medium density fibreboard
made from oil palm empty fruit bunch by Ramli et al. [9]. Overall
panels made from hot water treatment performed better in MOE
and MOR than those panels made from NaOH treatment. The IB
values for treated particles increased from 0.67 to 0.84 and
1.05 MPa for sodium hydroxide and hot water treatments,
respectively. Panel type made from hot water treated particles
showed the highest value of internal bonding strength which is
1.05 MPa as illustrated in Fig. 3. The increment was about
56.72% of control panels.
3.3. Evaluation on dimensional stability
Figs. 4 and 5 display the average values of thickness swelling
and water absorption for 24 h. The results showed the TS value
of board were in the range of 53.51–65.95% for 24 h immersion.
This phenomenon indicated that particles treatment with hot
water improved the dimensional stability of the board. Norul Izani
et al. [10] indicated the lowest values of water absorption and
thickness swellings for panel treated with hot water were 56.7%
and 16.9%, respectively. The water absorption test revealed that
the panel type treated with hot water indicated the lowest
absorption having a similar trend as TS. However there were no
substantial differences between control and hot water treated
panel. TS and WA actually related to internal bonding strength of
board. Zaidon et al. [15] mentioned that the low IB values indicate
that the particles were not effectively bonded together hence cannot
prevent the water from penetrating into particles. There is no
substantial effect of particle treatments on panel type for both values
of TS and WA, respectively.