Fig. 1. Modulus of elasticity of the samples.
Fig. 2. Modulus of rupture of the samples.
Fig. 3. Internal bond strength of the samples.
Fig. 4. Thickness swelling of the samples.
Fig. 5. Water absorption of the samples.
Fig. 6. FT-IR spectra of raw materials.
2.4. Fourier transform-infrared spectroscopy (FTIR) analysis
FTIR spectroscopy was used to evaluate the presence of functional
groups in different treatment of raw materials. In this analysis,
approximately 1 mg of particles were mixed with 99 mg of
potassium bromide (KBr) and pressed to form about 1 mm thickness
of pellet. To identify the functional groups of the pellet, Nicolet
infrared spectrophotometer (Avatar 360 FTIR E.S.P) between
wave numbers of 4000 cm1 and 400 cm1 with a resolution of
4 cm1 was used to analyze for each material.
2.5. Scanning electron microscopy (SEM) analysis
The morphological properties and bonding quality of raw material
after different treatments into the panels were observed by SEM. The cross section samples with dimensions of
0.5 cm 0.5 cm were taken from the panels. An ion sputter coater
Polaron SC515, Fisons Instruments, UK was used to coat the samples
with gold. The samples were viewed for microscopic analysis
using a scanning electron microscope LEO Supra 50 Vp, Carl Ziess
SMT, Germany.
2.6. Thermogravimetric analysis (TGA)
The obtained oil palm particleboards were subjected to analysis
by using a Perkin Elmer TGA 7 thermogravimetric analyzer for
thermal decomposition. The values were recorded with the heating
rate at 20 C/min from temperatures between 30 C and 800 C
under a nitrogen atmosphere.
3. Results and discussion
3.1. pH of particles
The pH values of particles before and after treatments ranged
between 4.62 and 9.79. Particles treated with hot water less acidic
with a pH value of 5.16 when compared to untreated particles having
a pH of 4.62 while the NaOH treatment made particles become
alkali with a pH value of 9.79. From a previous study, it was
reported that NaOH treatment produced poorer fiber which also
affected the mechanical and physical properties [14].