edi suhaimi bakar, 1 mohd. hamami sahri, 1 zaidon ashaari, 1 and fauzi febrianto 2 oil palm trunks a...

Edi Suhaimi BAKAR,1 Mohd. Hamami SAHRI,1 Zaidon ASHAARI,1 and Fauzi FEBRIANTO2

Oil Palm TrunksOil Palm Trunksa New Alternative Material for Solid Wood Productsa New Alternative Material for Solid Wood Products

1 Department of Forest Production Faculty of Forestry, Universiti Putra Malaysia 43400 UPM Serdang, Selangor, Malaysia

2 Department of Forest Products TechnologyFaculty of Forestry, Bogor Agric. University, PO. Box 168, Bogor, Indonesia

IntroductionIntroduction

● Wood supply issues: Shortage of wood supply, especially for solid wood Production from forest no longer sufficient to meet the demands Finding the alternative material of wood has become a central issue Any alternative must be sought– include agricultural residues.

● Oil palm trunks (OPT) as strategic wood alternative material: Huge oil palm planted area

By 2006: Malaysia = 4.2 million ha, Indonesia = 5.4 million ha Replanting at 25 years old: average annual rate 4% Produce huge amount residues (fronds, EFB, trunk) Trunk offer the best properties comparable to the wood About 250m3 OPT for each replanting hectare (most under utilized)

IntroductionIntroduction

● Characteristics of matured oil palm trunks: Consist of two main structure:

- vascular bundles- thick walled cells → high density- parenchyma tissues- thin walled cells → low density, more porous and starch

Vascular bundles are scattered in parenchyma tissues as matrix, with a reduced concentration from the outer to the inner

Great density gradient between trunk’s outer part (0.4 g/cm3) and center part (0.15 g/cm3).

Only the trunk’s outer part can be used as solid wood (Bakar, 2000)

● Characteristics of oil palm wood (OPW): Very low in strength Bad in dimensional stability Very low in durability Poor in machining characteristic

Need properties improvement

Objectives & MethodsObjectives & Methods

● To develop suitable sawing pattern for OPT ● To enhance the properties of OPW

Oil palm logOil palm log


● To develop suitable sawing pattern for OPT Being monocot (the best portions of wood at the outer part) the available

sawing patterns can not be used for OPT Three sawing patterns are compared (two are modified patterns):

- Live sawing (LS)- Polygon sawing (PS)- Cobweb sawing (CS)

Test materials:- 12 logs from 4 oil palm trees of 25-year-old (L: 2.5 m, D: 43–55 cm)- The logs ends were paint-coated in different color

Measurements:- Lumber Recovery: Outer-lumber, Middle-lumber, Center-lumber- Sawing time: Effective time, Ineffective time, Total time - Lumber width count occurrence of each width criteria of the outer lumber

(LS) (PS) (CS)


● To enhance the properties of OPW Material

- The outer lumbers OPW (0.33–0.4 g/cm3), dimension (40Tx100Rx100L) mm- Mmw-PF of various concentrations

Methods Modified Compreg- Drying: 15%- Impregnation

- Concentration : 10, 15, 20 %- Period : 1, 2, 3 hrs- Compression : 120 psi

- Re-drying (microwave, 1kWh) → partially cured resin- Period : 5, 7, 10, 15 min- Power output : high

- Hot pressing- Temperature : 150°C- Pressing time : 30 min- Pressing ratio : 50% (45%)

DryingDryingDryingDrying

ImpregnationImpregnationImpregnationImpregnation

Re-dryingRe-dryingRe-dryingRe-drying

Hot-pres Hot-pres DensificationDensification

Hot-pres Hot-pres DensificationDensification

MODIFIED COMPREG

Results & DiscussionResults & Discussion

Sawing StudySawing Study● LS provided the highest RT but the

lowest RO. Two-thirds of the results were the middle- and center-lumbers that were low in quality.

● CS produced the lowest RT (50%) but the highest RO (35%). Two-thirds of resulted lumbers were the outer-lumbers that were high in quality

● PS was in between, about half of resulted lumbers were the outer lumber

● CS is the most suitable sawing pattern in term of outer lumber recovery.

0

20

40

60

80

100

LS PS CS

Sawing patterns

Lu

mb

er R

eco

very

(%

) R-outer (RO) R-midle (RM)R-center (RC) R-total (RT)


Sawing StudySawing Study● LS consumed the shortest time

and CS pattern the longest in term of either the Tt or the Te.

● PS consumed about the same Te (6.7 min.) to the LS and the same Tt (46.0 min.) to the CS

● CS consumed as twice as longer Te (15.4 min.) than the LS and PS

● Both PS and CS patterns spent plenty of Ti (39 min.)

for cant adjustment.

● The LS is the most suitable sawing pattern in term of the sawing time.

0

15

30

45

60

LS PS CSSawing patterns

Saw

ing

Tim

e (m

in.)

T-efective (Te)T-inefective (Ti)T-total (Tt)


Sawing StudySawing Study● LS and CS tend to produce

narrow strips which is consider low in quality, while PS pattern tend to produce wider lumber which is high in quality:

Board <10cm: LS (77%), CS (88%), PS (47%)

Board >20cm: CS (0pc), LS (1pc), PS (3pcs)

● The PS was the most suitable sawing pattern in term of the outer lumber width

0

5

10

15

20

25

LS PS CS

Sawing patterns

Wid

th C

ou

nt

> 20 cm 16-20 cm 11-15 cm 5-10 cm < 5 cm

41


Sawing StudySawing Study● After considering all the parameters above, it can

be concluded that the Polygon Sawing is the most suitable pattern for the sawing of OPT.

(PATENT P.20001099)

● The Polygon Sawing can produce wide outer-lumbers which are high in quality, with recovery of 27%.

● Skilled operators and good carriage are needed to run the Polygon Sawing efficiently.

● Potential OPW production in Malaysia:

= 4,2 millions x 4% x 250m3 x 27%

= 11.34 million m3/year

POLYGON SAWING


Properties Enhancement StudyProperties Enhancement Study● Being impregnated and densified, the

density of OPW increased almost 3x from 0.37 g/cm3 to almost 1.00 g/cm3.

● The amount of PF resin penetrated, WPG, depend on PF concentration and impregnation period.

● These result suggested that 1-2 hrs impregnation was sufficient to impregnate the mmw-PF into OPW structure.

● This is a very short period compare to impregnation of softwood that need 24 hrs even with a lmw-PF resin as reported by Furuno [3].

0

10

20

30

40

50

10% 15% 20%PF Concentration

WP

G (

%)

1 hr 2 hrs 3 hrs


Properties Enhancement StudyProperties Enhancement Study● Anti swelling efficiency (ASE) that

indicate dimensional stability achievement of treated OPW was 30%

● There was no significant influence in increasing the solution concentration and impregnation period to the ASE value

● These suggested that short impregnation (1 hr) with low concentration mmw-PF resin (10-15%) is good enough to enhance the dimensional stability of OPW

0

10

20

30

40

50


AS

E (

%)

1 hr 2 hrs 3 hrs


Properties Enhancement StudyProperties Enhancement StudyThe mechanical properties of treated OPW were substantially improved

● Young’s Modulus at the compression parallel to the grain increased from 170 to 2600 MPa ………..(15x)

● Shear strength increased from 1.9 to 13 MPa ………… (7x)

0

500

1000

1500

2000

2500

3000


Co

mp

ressio

n /

/ g

rain

(M

Pa)

1 hr 2 hrs 3 hrs

Ctr=

170 0

4

8

12

16


Sh

ear

str

en

gth

(M

Pa)

1 hr 2 hrs 3 hrs

Ctr=

1.85


Properties Enhancement StudyProperties Enhancement Study● Even the mmw-PF might not penetrate into vascular bundles, it could

immediately penetrate into the parenchyma tissues.

● PF penetration to parenchyma tissues improve density/strength, durability and dimensional stability of whole OPW, and reduces density gradient between the vascular bundle and parenchyma tissues.

● Reduction in the density gradient resulted in better machining characteristic.

● The method can practically solve the four OPW flaws concurrently.

UNTREATED OPWTREATED OPW

ConclusionsConclusions

● The outer-part of OPT provide the best quality wood (OPW) that can be used as solid wood after properly treated.

● Polygon sawing is the best suited pattern to saw OPT. Sawing recovery of 27% can be achieved.

● Potentially about 11 million m3 OPW timber can be resulted in Malaysia annually. This timbers have four flaws that need to cope with before utilization.

● Modified compreg method with mmw-PF can solve all OPW flaws concurrently.

● Treated OPW timbers can be used as a new alternative material for diminishing solid wood.

● Utilization of OPW (upon treatment) may reduce our dependency on wood from the forest, and at the same time could solve the facing problem in the plantation industry.

ReferencesReferences

[1] Bakar, E.S., Y.S. Hadi. 2001. Indonesian J. For. Prod. & Techno. Vol. XIV (2): 24-31.

[2] Ibach, R.E. 2005. Lumen Modifications, In Rowel, R.M. (Ed.), Handbook of Wood Chemistry and Wood Composites. Taylor & Francis. N.Y.

[3] Furuno, T., Y. Imamura, H. Kajita. 2004. Wood Sci. Technol. 37: 349-361.

[4] Bakar, E.S., P. Md. Tahir, and Mohd. H. Sahri. 2005. Internat. Sympo. on Wood Sci. and Techno. Yokohama, Nov. 27-30.

[5] Rahaya, I.S. 2001. Basic Properties of Vascular Bundles and Parenchyma of Oil Palm Wood. Thesis at School of Graduate Study, Bogor Agric. Univ. (IPB), Indonesia.

edi suhaimi bakar, 1 mohd. hamami sahri, 1 zaidon ashaari, 1 and fauzi febrianto 2 oil palm trunks a...

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