This is my viva vorce slide for my master degree

1. PROPERTIES OF LOW DENSITY WOOD IMPREGNATED
WITH PHENOLIC RESIN ADMIXED WITH UREA
Supervisory Committee:
Associate Professor Dr. Zaidon Ashaari
Professor Dr. Hamami Sahri
Associate Professor Dr. Edi Suhaimi Bakar
NUR IZREEN FARAH BINTI AZMI
GS 24471
Master Of Science
(Wood Science & Technology)

2. OUTLINE OF PRESENTATION
• Introduction
• Problem Statement
• Objectives
• Literature Review
• Methodology
• Statistical Analysis
• Result And Discussion
• Conclusions
• Recommendations
• References

3. INTRODUCTION
• World demand for forest wood product is growing since the past years;
• Rapid declining of the global availability of precious commercial timbers;
• Industries need to find another alternative;
• Issue of underutilized wood species;
• A lot of potentially valuable trees being left over after forest clearing operations.
Have a great potential
and is extensively being
used in research study
Limitations:
•Low natural durability
•Poor strength properties
Dyera constulata Endospermum diadenum
•Dimensional instability
Advantages:
•Faster grow
•Exotic colors and
textures
•Cheaper price
•Abundance availability
Macaranga sp. Azadirachta excelsa

4. CONT..
• Modify wood to improve the properties, depending on the ultimate applications;
• Sufficient amount of wood raw material for incoming years for the development
and growth of forest product industry;
• Impregnation of solid wood with Lmw-PF resin + cured using heat: provide
tremendous wood enhancement properties includes mechanical strength,
dimensional stability in terms of ASE and durability of wood against decay
(Zaidon et al. 2009, 2010, 2011; Nur Izreen et al. 2011)
Impreg wood Compreg wood
Resin treated wood cured with Resin treated wood compressed
heat without compression while the resin is cured in the
wood structure

5. PROBLEM STATEMENT
• High level of formaldehyde emission (FE) compared to required global standard;
• Generated from free, unreacted formaldehyde during curing;
• Harmful to human body; human carcinogen (cancer causing agent) (WHO)
• High number of methylol groups in the main polymer chains of Lmw-PF resin
responsible for the longer time required to cure the resin (Hoong et al. 2010);
• Formaldehyde scavenger: urea, ammonium phosphate, potassium sulphite and
sodium thiosulphate (Roffael, 1993);
• Urea: low cost and can improve curing process (Zaidon, 2009) ;
• Able to reduce FE from compreg products made from sesenduk (Endospermum
diadenum) and mahang (Macaranga sp.) (Zaidon, 2009, 2010, 2011) and impreg
product made form jelutong (Dyera constulata) (Nur Izreen et al. 2011);
• Unfortunately, when enough urea is mixed to achieve significant reduction of FE,
some of physical properties of the resultant product are severely affected;
• Introduced urea will react with the free formaldehyde and form a rigid cross-linked
polymer of urea-formaldehyde (UF) and phenol-urea formaldehyde (PUF).

6. OBJECTIVES
• Main objective:
– To determine the effect of phenolic resin admixed with urea (formaldehyde
scavenger) on the properties of low density wood, Dyera constulata and
Endospermum diadenum.
• Specific objectives:
– To investigate the FE of Dyera constulata and Endospermum diadenum
impregnated with Lmw-PF admixed with urea using vacuum pressure
process;
– To identify the functional groups of compound presence in the treated
wood using Fourier Transform Infrared Spectroscopy (FT-IR);
– To evaluate the effect of processing variables on mechanical properties,
dimensional stability and decay durability of the impregnated wood.

7. LITERATURE REVIEW
– As timber resources become scarcer, and the real prices of primer species
rise, the underutilized wood species and small-sized logs will gain wider
acceptance;
– Impregnation treatment: depositing any of a bulking agent within the
swollen wood structure;
– No reaction taking place -monomers are not attached or bonded to the cell
wall components but change from soluble monomers into water-insoluble
polymers after polymerization which will not leach out in water
(Nonbonded-nonleachable );
– Kajita and Imamura (1991) used the Lmw-PF resin to improve the physical
and biological properties of particleboards while Anwar et al. (2006) and
Loh et al. (2011) studied the properties improvement by using the resin on
bamboo strips and oil-palm stem veneer respectively.

8. METHODOLOGY
• Materials
– Low density wood, jelutong (Dyera constulata)
and sesenduk (Endospermum diadenum), obtained
from Ayer Hitam Forest Reserve, Puchong, Selangor;
– Low molecular weight phenol formaldehyde (Lmw-PF)
resin (Mw 600, 45% solid content), supplied by
Malaysian Adhesive Chemical, Shah Alam;
– Urea in the form of granules, as formaldehyde
scavenger, readily available in the market

9. PREPARATION OF SAMPLES
Flat sawn into samples Rank according to density; each group
Jelutong : 150x50x5mm contain samples with varied density
Sesenduk: 150x50x10mm
Treatment combinations:
3 treating concentrations;
3 curing time;
Untreated samples (control)
(3 x 3 x 1)
Measure weight and dimension

10. PREPARATION OF MATERIALS
Dilute Lmw-PF into 20, 30, 30% urea based on solid PF
40% concentration
pH for PF admixed
with urea: 9-11
(alkaline)
Mix with prepared PF resin
separately

11. TREATMENT PROCESS
Measure initial weight Apply some loads
85kPa vacuum, 15 min
340kPa
pressure, 30 min
Precure:60°C for 30 min
Cure: 150°C for 60, 90, 120 min Fill with treating solution
(Based on preliminary study)

12. PROPERTIES EVALUATION
Vacuum-soaking &
water vapour test for
Formaldehyde dimensional stability
emission test
Decay resistance
test
MOR and MOE in FTIR analysis
bending test

13. STATISTICAL ANALYSIS
• Statistical analysis was carried out using a two-way analysis of variance
(ANOVA) to evaluate the effects of treatment combinations on the
formaldehyde emission, physical and mechanical properties, dimensional
stability, and durability on impreg product. Duncan Multiple Range Test
(DMRT) at p ≤ 0.05 was used to further evaluate these effects.

14. RESULT & DISCUSSION
Summary of ANOVA (p ≤ 0.05)
Variables df Density WPG MOR MOE ASE1 WA1 TS1 ASE2 WA2 TS2 Fungal
Jelutong
Con 2 0.000 0.576 0.173 0.028 0.582 0.000 0.000 0.099 0.001 0.401 0.000
Cur 2 0.001 0.007 0.677 0.126 0.551 0.000 0.002 0.007 0.000 0.011 0.000
Con*cur 4 0.747 0.913 0.173 0.333 0.719 0.124 0.075 0.545 0.231 0.100 0.000
Sesenduk
Variables df Density WPG MOR MOE ASE1 WA1 TS1 ASE2 WA2 TS2 Fungal
Con 2 0.047 0.087 0.265 0.092 0.009 0.000 0.047 0.000 0.000 0.003 0.000
Cur 2 0.001 0.007 0.311 0.962 0.920 0.768 0.877 0.927 0.020 0.173 0.002
Con*cur 4 0.044 0.290 0.936 0.878 0.039 0.349 0.127 0.032 0.404 0.073 0.011
Note: Mean in bold properties significantly affected by treatment variables at p≤0.05

15. FORMALDEHYDE EMISSION
3.5
y = 9.089x - 0.068
3 R² = 0.997
2.5
Std.Solution (ppm)
2
1.5
1
0.5
0
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Absorbance

16. CONT..
Jelutong Sesenduk
NU+90 min WU+60 min WU+90 min WU+120 min NU+90 min WU+60 min WU+90 min WU+120 min
180 166.11 200 187.99
Formaldehyde Emission, ppm
Formaldehyde Emission, ppm
160 180
140 160 141.97
130.95
120 105.08 140
100 120 83.42
78.06 100 36.6 48.45
80 42.82 80
33.26 36.89 35.19 44.81 50.97
60 29.93 60 42.96 44.07
10.03 13.82
40 14.81 40 23.59
20 8.38 13.46 20
0 0
20% 30% 40% 20% 30% 40%
PF concentration,% PF concentration, % 70%
90%
Urea successfully absorbed some of free formaldehyde in the resin system during polymerization;
Reactive urea easily bond with the free formaldehyde released by some of methylol
groups from the resin;
Min (8.38 ppm) still far beyond the global standard threshold limits 0.1ppm for indoor applications;
FE with curing time -methylol group in oligomeric chain of PF converted to methylene bridge;
Another alternatives:
increase the concentration of urea;
prolong the curing time

17. FT-IR ANALYSIS
Literature Observed Compound/ Band
wavenumber (cm-1) Wavenumber (cm-1) Functional group numbers
3336 3335 O-H stretch 1
120 Jelutong N-H stretch
100 2882 2887 CH- stretch in methyl- 2
80 and methylene groups
20%
60 3 30%
1722 1733 C=O stretch 3
2
40 5 40% 1633 1640 C=C aromatic ring 4
4
6 Control
20 1 1478 1467 C-H aliphatic 5
0
7
1227 1227 C-O stretch 6
934
715
496
4000
3781
3562
3343
3124
2905
2686
2467
2248
2029
1810
1591
1372
1153
1020 1020 -C-OH 7
120 Sesenduk
•Kornel et al. 1992 detected a significant bands of pure
100
UF resin with a pronounced peak Band 1 at 3336 cm-1;
80
20%
•PUF resin: synthesized by the reaction of TMeP with
60 3 urea, under acidic or alkaline conditions (Poljansek and
2 30%
40
40% Krajnc (2005);
20 4 5
6 Control •Addition of urea to Lmw-PF results in the formation of
1
0 7 cocondensed PUF resin; shown by Band 6 (1227 cm-1)
971
738
505
4000
3767
3534
3301
3068
2835
2602
2369
2136
1903
1670
1437
1204
which corresponded to the C-O stretch vibrations of
phenolic rings.

18. PHYSICAL PROPERTIES
Treatment Density Density Gain WPG
combination (kg/m3) (%) (%)
Jelutong
Untreated 396E - -
Density 20% 60 min 59.1
630CD 84.13AB
2-3 folds; 20% 90 min 594D 50.0 64.31BC
PF resin monomer was successfully 20% 120 min 583D 47.2 54.55C
penetrate into the wood cellular structure 30% 60 min 744AB 87.9 85.31AB
and filled up the void vessels of wood. 30% 90 min 690BC 74.2 75.03BC
30% 120 min 649CD 63.9 68.55BC
40% 60 min 797A 101.3 91.06A
Weight Percent Gain 40% 90 min 759AB 91.7 80.93AB
(based on constant weight in conditioning 40% 120 min 698BC 76.3 77.51BC
room before and after treatment) Sesenduk
50-100%; Untreated 348E - -
High WPG indicates that the PF solution 20% 60 min 737ABC 112.4 105.2B
has penetrated and bulked into the cell wall; 20% 90 min 697BCD 100.9 84.43BCDE
with curing time -partly cure resin may 20% 120 min 636D 83.3 70.79E
consist of some water molecule which would 30% 60 min 797A 129.7 127.5A
add to the weight of the treated wood. 30% 90 min 742ABC 113.8 95.46BCD
30% 120 min 669CD 92.8 75.24DE
40% 60 min 802A 131.1 101.9BC
40% 90 min 749AB 115.9 83.11BCDE
40% 120 min 704BCD 102.9 80.34CDE

19. MECHANICAL PROPERTIES
MOR 10-50%
Treatment MOR MOE MOE 20-70%
combination (MPa) (MPa)
R² = 0.4685 R = 0.6845
Jelutong 90
B D 85
Untreated 62.95 6124
A BC
20% 60 min 79.40 8255 80
MOR, Mpa
A AB
20% 90 min 80.70 9579
AB 75
20% 120 min 77.73 8903ABC
AB C
30% 60 min 70.31 7752 70
A ABC
30% 90 min 80.90 8744 65
BC
30% 120 min 69.98AB 8442
80.71
A
9192
ABC 60
40% 60 min
78.57
A
8985
ABC 600 700 800 900
40% 90 min
A A Density, kg/m3
40% 120 min 83.92 10432
Sesenduk Failure mode:
B B
Untreated 55.91 5064
AB A
20% 60 min 77.63 7914
AB A
20% 90 min 70.92 7776
A
20% 120 min 73.20AB 7603
A
30% 60 min 81.10 8135A
AB
30% 90 min 70.25 7631A
AB
30% 120 min 66.93 7840A
85.34
A Untreated : Impreg :
40% 60 min 8359A
40% 90 min 83.59
A Splintering tension Simple tension
8937A
AB
40% 120 min 76.69 8630A

20. DIMENSIONAL STABILITY
Treatment ASE1 WA1 TS1 ASE2 WA2 TS2
combinations (%) (%) (%) (%) (%) (%)
Jelutong
• ASE: bulking of cell wall 20% 60 min 28.26AB 43.56B 2.00BCD 10.14A 13.12B 5.09AB
and reduction in 90 min 27.67AB 38.19C 1.07EF 18.92B 10.37C 4.23BCD
hydrophilicity of wood after 120 min 35.39A 36.82CD 0.82F 25.21C 9.69C 4.02BCD
30% 60 min 4.92C 35.88CD 3.01B 13.28A 13.90B 4.49BC
modification
90 min 15.84BC 33.57D 2.71BC 12.54A 9.69C 4.52BC
120 min 14.02BC 26.64E 1.80CDEF 26.45C 9.20C 3.09D
• Aikfe (2010) found ASE 40% 60 min 17.94BC 24.72E 2.85B 25.91C 10.24C 4.66BC
of Macaranga spp. treated 90 min 25.98AB 20.55F 1.52DEF 26.08C 8.60C 3.54CD
without urea was more 120 min 14.41BC 19.91F 2.51BCD 26.97C 8.47C 4.26BCD
than 60%. Control - 63.17A 4.18A - 18.96A 5.9A
Sesenduk
• The presence of urea 20% 60 min 36.66ABC 67.98B 3.01BCD 23.56BC 11.32B 3.25BC
increased Mw of resin 90 min 31.17C 69.10B 3.30B 21.68C 10.81BCD 3.37B
120 min 34.94BC 70.46B 3.06BCD 18.13C 11.04BC 3.28BC
system, thus limit the
30% 60 min 40.02ABC 41.35C 2.64BCD 13.03C 10.21CD 3.10BC
penetration into the cell 90 min 39.13ABC 46.47C 2.91BCD 23.30BC 9.99D 2.61CD
wall of treated wood. 120 min 31.43C 45.11C 3.19B 16.45C 10.00D 3.11BC
40% 60 min 37.30ABC 45.15C 3.12BCD 36.86A 10.04D 3.14BC
90 min 42.89AB 30.81D 2.24CD 25.24ABC 9.01E 2.66CD
*Note: 1= water soaking test (24h) 120 min 44.87A 29.37D 2.17D 34.23AB 8.89E 2.26D
2= water vapour test (constant weight) Control - 208A 5.30A - 17.15A 4.18A

21. Cont..
Jelutong Sesenduk
CT60 min CT90 min CT120 min Control Control CT60 min CT90 min CT120 min
30
30
25
25
20 20
WA, %
WA, %
15 15
10 10
5 5
0 0
0 5 10 15 20 25 0 5 10 15 20 25
Day Day
CT60 min CT90 min CT120 min Control Control CT60 min CT90 min CT120 min
8.0
6
7.0
6.0 5
5.0 4
TS, %
TS, %
4.0 3
3.0
2
2.0
1
1.0
0.0 0
0 4 8 12 16 20 24 28 0 5 10 15 20 25
Day Day

22. DURABILITY
12 weeks of exposure to Pycnoporous sanguiness:
Jelutong
18.40
20.0
60 min 90 min 120 min
15.0
10.0
4.80
3.42 2.20 0.60
5.0 1.10
0.00 0.60
0.00 0.00
0.0
Control 20% 30% 40% Untreated Treated
Sesenduk
26.30
30.0
25.0 60 min 90 min 120 min Average Weight Loss Indicated Resistance Class
(%)
20.0
15.0 0-10 Highly Resistant
4.20
10.0 4.00 11-24 Resistant
3.20 1.10
3.10 3.30
5.0 1.20 0.30 0.30
25-44 Moderately Resistant
0.0
Control 20% 30% 40% 45-100 Slightly Resistant or Nonresistant

23. Effect of FE levels on WL
Jelutong Sesenduk
40 20 70 20
35 18 18
16 60
30 16
FE (ppm)
14
WL (%)
50 14
25 12 12
FE (ppm)
WL (%)
40
20 10 10
15 8 30 8
6 20 6
10
4 4
5 2 10
2
0 0 0 0
20 30 40 20 30 40
PF Concentrations (%) PF Concentrations (%)

24. CONCLUSIONS
• The addition of 30% urea scavenger based on solid PF greatly reduced the level of
FE for both wood species by 70-90%. The significant reduction however still far
beyond the global standard threshold limits.
• The addition of urea to Lmw-PF resulted in the formation of UF and cocondensed
PUF resin. This was shown by FT-IR at the absorption peak 3335 cm-1 and 1227 cm-1
respectively.
• The properties of impreg Dyera constulata and Endospermum diadenum treated with
Lmw-PF resin was superior than the untreated wood, indicating that the treatment
had successfully improve the strength, dimensional stability and durability against
fungi attack.

25. RECOMMENDATIONS
 Treatment with 40% Lmw-PF admixed with urea and cure for 120 min is
recommended to compensate the properties of jelutong and sesenduk which
can be used for producing impreg product for parquet
flooring, paneling, furniture components and also for exterior applications.
 For further studies, 30% urea based on solid PF can be used to reduce
formaldehyde emission since it has been proven able to reduce the level of FE
up to 90%. However, the curing time should be prolonged so that more
polymerization would occur.

26. REFERENCES
• Hoong, Y.B., Paridah, M.T., Loh, Y.F., Koh, M.P., Luqman, C.A., and Zaidon, A. 2010.
Acacia mangium tannin as formaldehyde scavenger for low molecular weight phenol
formaldehyde resin in bonding tropical plywood. Journal of Adhesion Tech. 24: 1563-
1664.
• Kajita, H., and Imamura, Y. 1991. Improvement of physical and biological properties of
particleboards by impregnation with phenolic resin. Journal of Wood Sci. Tech. 26: 63-70.
• Nur Izreen, F.A., Zaidon, A., Rabiatol Adawiah, M.A., Bakar, E.S., Paridah, M.T., Mohd
Hamami, S., Anwar, and U.M.K. 2011. Enhancing the Properties of Low Density
Hardwood Dyera constulata Through Impregnation with Phenolic Resin Admixed with
Formaldehyde Scavenger. Journal of Applied Science. 11(20): 3474-3481.
• Rowell, R.M., and Youngs, R.L. 1981. Dimensional stabilization of wood in use. U.S. For.
Serv., For. Prod. Res. Note FPL-0243. Forest Product Laboratory, Wisconsin.
• Wallström, L., Lindberg, K.A.H. 1999. Measurement of cell wall penetration in wood of
water-based chemicals using SEM/EDS and STEM/EDS technique. Wood Sci Technol.
33: 111–122.
• Zaidon, A. 2009. Improvement of raw materials from underutilised timber species through
chemical and densification treatments for value added laminated products. End of Reports
(unpublished) submitted to the Ministry of Science and Technology, Malaysia. Rep. No.
06-01-04-SF0656.

28. PRELIMINARY STUDY
• Objective: To determine the curing time of LmwPF;
• Justification: Important to estimate the time required for the complete
polymerization in the treated wood;
• Methods: 1) Determination of PF hardening time
• Diluted PF with distilled water to produce 20%, 30% and 40% Lmw-PF;
• Poured 50 ml of the prepared PF solution separately into a petri-dish;
• Heated in an oven at 150ºC;
• Observed the hardening process every 5 min and record the time of PF resin
start to harden.

29. • Methods: 2) Determination of heat transfer into wood
• Use thermocouple meter to measure the time required for the heat to
transfer into the central part of the wood;
• Drill a small hole on the center of sample;
• Insert thermocouple wire into the hole of the wood, and the wood is
partly immersed into the oil bath at 150±2ºC
• Record the time required for the hole to reach 150±2ºC.
Result:
PF PF Heat Curing
concentration hardening transfer resin
(%) time (min) into wood (min) (min)
20 60 30 60 + 30 = 90 60-120 min was
30 55 30 55 + 30 = 85
selected for curing time
40 50 30 50 + 30 = 80
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