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BONDING PERFORMANCE OF TROPICAL FAST-GROWING WOOD SPECIES –BONDABILITY OF SIX INDONESIAN WOOD SPECIES IN

RELATION WITH DENSITY AND WETTABILITY-

EKA MULYA ALAMSYAH THE UNITED GRADUATE SCHOOL OF AGRICULTURAL SCIENCES, GIFU UNIVERSITY

MASAAKI YAMADA AND KINJI TAKI FACULTY OF AGRICULTURE, SHIZUOKA UNIVERSITY

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INTRODUCTION

GLOBAL PLANTATION FOREST

187,086World Total79%Top 10%

148,403Top 10 total2,284Islamic Republic of Iran4,425Ukraine4,920Thailand4,982Brazil9,871Indonesia10,682Japan16,238United States17,340Russian Federation32,578India45,083China

Total area (1000ha)Country

Table. Plantation area for the 10 largest plantation development countries (Carle J, et.al, 2002)

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GLOBAL PLANTATION FOREST

17%

9%9%

6%

5%

3%

3%

2%

1%

21% 24%

China

India

Russian Federation

United State

Japan

Indonesia

Brazil

Thailand

Ukraine

Islamic Republic of Iran

Others

Fig. Leaders in forest plantation development, percentage of area (Carle J, et.al, 2002)

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Table. Wood resources of selected species in Indonesian plantation forest

1110 – 35Gmelina arboreaGmelina143020Shorea spMeranti kuning133020Shorea spMeranti putih123020Shorea spMeranti merah113026Shorea stenopteraTengkawang10525Leucaena leuchochepalaLamtoro9

5 – 1025 – 44Acacia mangiumMangium81023Acacia auriculiformisAkor71012Anthocepalus sinensisJabon61520Dalbergia latifoliaSonokeling51225Eucalyptus albaAmpupu4

10 – 2517 – 20Eucalyptus degluptaLeda315 – 3016 – 18Pinus merkusiiTusam210 – 1538 – 45Paraserianthes falcatariaSengon1

Rotation (year)Annual increment (m3/ha)

Botanical nameVernacular nameNo

Source: Prosea foundation (1995)

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Acacia mangium Willd

a major fast-growing wood species

Description: Tree to 30m tall, bole often straigth, to over half the total tree height. Possible to utilized for particleboard, furniture, cabinet marking, and pulp and paper.

Distributon: Largely Australian (native) with small stands New Guinea and the Moluccas. Introduced to Bangladesh, Cameroon, Costa Rica, Hawaii, Indonesia, Malaysia, Nepal, Papua and the Philippines.

Yields: Very fast growing species attaining 15m height and 40cm DBH in 3 years. They have attained 23 m tall in 9 years (Duke JA, 1983)

Area in 2003: 800,000 ha

Proposed in 2010: 1,000,000 ha

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Development ofPlantation Forest

Pulp and paper,Latex,MDF

Natural ForestLumber,Wood working,etc.S

UPPLY

Bonding performancePrevious study

Glulam???

Recent study

DEMAND

Facing the increasingly wood of fast-growing tree species from plantation forest in the future, more attention must be given to these fast-growing tree species. This is because these species are expected to be used not only for pulp and paper or fiber production but also for other wood bonded products such as for glulam production which is deserving of the most promotion in the future.

BACKGROUND

OBJECTIVEIn order to get more efficient and appropriate utilization of these fast-growing wood species for glulam production, the study of wood characteristics such as density and wettability related to its bonding performance is still great important.

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Table 1. Wood speciesSpecies Symbol Age (year-old) Diameter (cm) Height (m) Density (g/cm3) MC (%)

Enterolobium xylocarpum Ex 7 28 11 0.30 9.5Paraserianthes falcataria Pf 8 30 10 0.34 9.3Toona sinensis Ts 11 11 10 0.49 9.0Gmelina arborea Ga 11 28 10 0.51 9.3Pinus merkusii Pm 11 23 12 0.59 9.3Acacia mangium Am 7 31 10 0.64 9.0MC, moisture content

MATERIALS I. Shear strength and wood failure

Paraserianthes falcataria Enterolobium xylocarpum Toona sinensis

Gmelina arborea Pinus merkusii Acacia mangium

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Table 2. Adhesives

59±1

58±3

55

42

Solid content (%)

0.35

6.0±2

0.25

n.a

Viscocity(Pa.s)

250resin (100) : catalyst (15)Resorcinol formaldehyde (RF)

250resin (100) : cross link agent (15)

Aqueous polymer isocyanate (API)

300resin (100) : NH4Cl 20% (15) : flour (10)

Urea formaldehyde (UF)

200-Polyvinyl acetate emulsion (PVAc)

Spread rate (g/m2)

Glue mixture composition (p.b.w)

Adhesive type

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METHODS

Two-ply laminations preparation

Laminae (230×120 × 10mm) Smoothened Conditioned in 20oC, 65%RH for 24h

Glued spread two-ply laminaeAssembledCold pressurized in 20oC, 65%RH for 24h

Cured conditioned in 20oC, 65%RHfor 1 week

Block-shear tested (6.25cm2)10 specimen per each treatment

Bond strength (BS) and wood failure (WF) Wood strength (WS)

Solid wood

Glue line

Load

Load pressure: 0.98MPa in EX, PF, S, TS, GA, PM 1.18MPa in AM, AH

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Test condition: Normal (N) and after accelerated aging treatment

Specimen submerged in cold tap water for 1h→vacuumed at 635mmHg for 5m→ pressurized at 5.2±0.3kgf/cm2 for 1h → these step repeated→dried at 70±3oC for 24h

OOVacuum pressure soaking-dry (PSD)

Specimen submerged in cold tap water for 1h→vacuumed at 635mmHg for 5m→ pressurized at 5.2±0.3kgf/cm2 for 1h → these step repeated

OOVacuum pressure soaking (VPS)

Specimen submerged in boiled water for 4h→submerged in cold tap water for 1h→ dried at 70±3oC for 18h → submerged in boiled water for 4h

OOCyclic boiling (CB)

RFAPI

Specimen submerged in hot water at 60oC for 6hOOHot water dipping (HW)

Specimen submerged in cold tap water for 6h→dried at 40oC for 18h

OOWater dipping-dry (WD)Specimen submerged in cold tap water for 6hOOWater dipping (W)

MethodUFPVAcTreatment

Table Description of accelerated aging treatment

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Maximum load at failure Shear strength (MPa): -----------------------------------

Glued area

Wood failure: the rupturing of wood fibers in strength test of bonded wood joints usually expressed as the percentage of the total area involved that shows such failure (Vick CB, 1999)

Bonding performance classifications

1. Excellent, if the strength retention and wood failure percentages are in the ranges from 80 to 100%

2. Good (60-79%)

3. Bad (40-59%)

4. Worst (0-39)

Where:Bond shear strength (BS)

Strength retention (%): ---------------------------------------- X 100 Wood shear strength (WS)

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RESULTS AND DISCUSSION

Fig. Relationship between density and strength in solid wood

y = 30.837x - 0.6834R2 = 0.9037

y = 20.499x - 1.2316R2 = 0.7288

0.0

5.0

10.0

15.0

20.0

25.0

0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90

Density (g/cm3)

Shea

r st

reng

th (M

Pa)

Ex Pf Ts Ga Pm Am Japanese wood (42 species)

Note: Japanese wood (Wood materials handbook, forestry and forest products research institute, in Japanese, 192-195, Maruzen, 2004)

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Shear strength and wood failure

0

5

10

15

20

25

N (Dry) W (Wet) WD (Dry) HW (Wet)

Treatment

Shea

r str

engt

h (M

Pa)

Ex Pf Ts Ga Pm Am

020406080

100

Woo

d fa

ilure

(%)

0

5

10

15

20

25

N (Dry) W (Wet) WD (Dry) HW (Wet)

Treatment

Shea

r str

engt

h (M

Pa)

Ex Pf Ts Ga Pm Am

020406080

100

Woo

d fa

ilure

(%)

JAS

JAS

JAS

JAS

PVAc UF

14

PF

PM

TS

AM

EX

GA

Max Min

Fig. Type of failure for laminates bonded with PVAc in normal conditions

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PF

PM

TS

AM

EX

GA

Max Min

Fig. Type of failure for laminates bonded with UF in normal conditions

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Shear strength and wood failure

API

05

10152025

N (Dry) CB (Wet) VPS (Wet) VPSD(Dry)

Treatment

Shea

r str

engt

h (M

Pa)

Ex Pf Ts Ga Pm Am

020406080

100

Woo

d fa

ilure

(%)

0

5

10

15

20

25

N (Dry) CB (Wet) VPS (Wet) VPSD(Dry)

Treatment

Shea

r str

engt

h (M

Pa)

Ex Pf Ts Ga Pm Am

020406080

100

Woo

d fa

ilure

(%)

JAS

JAS

JAS

JAS

RF

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PF

PM

TS

AM

EX

GA

Max Min

Fig. Type of failure for laminates bonded with API in normal conditions

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y = 32.96x - 3.8703R2 = 0.6225

0.0

5.0

10.0

15.0

20.0

25.0

0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90

Density (g/cm3)

Shea

r st

reng

th (M

Pa)

Ex Pf Ts Ga Pm Am

y = 20.705x + 1.1439R2 = 0.6011

0.0

5.0

10.0

15.0

20.0

25.0

0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90

Density (g/cm3)

Shea

r str

engt

h (M

Pa)

Ex Pf Ts Ga Pm Am

y = 29.046x - 1.0988R2 = 0.7152

0.0

5.0

10.0

15.0

20.0

25.0

0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90

Density (g/cm3)

Shea

r st

reng

th (M

Pa)

Ex Pf Ts Ga Pm Am

y = 27.355x - 0.5092R2 = 0.7355

y = 18.185x - 0.0584R2 = 0.7305

0.0

5.0

10.0

15.0

20.0

25.0

0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90

Density (g/cm3)

Shea

r stre

ngth

(MPa

)

Ex Pf Ts Ga Pm Am Japanese wood (39 species)

UF PVAc

Relationship between density and shear strength

API RF

Note: Japanese wood (Horioka K, report of forest research laboratory, 1956)

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PF

PM

TS

AM

EX

GA

Fig. Type of failure for laminates bonded with RF in normal conditions

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0102030405060708090

100

0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90

Density (g/cm3)

Woo

d fa

ilure

(%)

Ex Pf Ts Ga Pm Am

0102030405060708090

100

0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90

Density (g/cm3)

Woo

d fa

ilure

(%)

Ex Pf Ts Ga Pm Am

0102030405060708090

100

0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90

Density (g/cm3)

Woo

d fa

ilure

(%)

Ex Pf Ts Ga Pm Am

0102030405060708090

100

0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90

Density (g/cm3)

Woo

d fa

ilure

(%)

Ex Pf Ts Ga Pm Am Japanese wood (39 species)

PVAc UF

Wood failure transition based on the density

API RF

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Solid wood Table 3. Wood shear strength (MPa) in average

N W WD HW CB VPS VPSDE. xylocarpum 7.5 5.6 9.0 5.4 4.7 5.7 8.3P. falcataria 10.4 4.8 9.7 5.5 4.7 5.9 7.0T. sinensis 16.3 11.8 17.7 10.0 8.9 10.8 18.0G. arborea 16.5 15.6 14.8 14.7 10.4 12.8 15.6P. merkusii 17.2 7.3 16.3 6.7 6.0 6.6 17.0A. mangium 18.1 13.4 16.5 12.3 9.3 12.0 17.1

Wood species Treatment

Bonding performance……….

Bond shear strength (BS) 1. Strength retention (%): ---------------------------------------- X 100

Wood shear strength (WS)

2. Wood failure percentage

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T a b le 4 . E s tim a tio n o f b o n d in g p e r fo rm a n c e

N W W D HW C B V P S V P S DP V Ac

UFAP IRF

P V AcUFAP IRF

P V AcUFAP IRF

P V AcUFAP IRF

P V AcUFAP IRF

P V AcUFAP IRF

S p e c ie s Ad h e s iv e T re a tm e n t

E . x y lo c a rp u m

A . m a n g iu m

P . fa lc a ta r ia

T . s in e n s is

G . a rb o re a

P . m e rk u s i i

Excellent Good Bad Worst

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II. NATURE WETTABILITYMATERIALS

Specimen: laminae of each wood species Repetition: 3 specimen of laminaeLiquid dropped: distilled water (pH 5.76)

METHODSSpecimen manufactured

(60 x 20 x 5mm)Conditioned in 20oC,

65%RH for 24hLaminae Smoothened

Contact-angle changes measured three times (every 10second within

120second observation time)

Distilled water dropped (0.20ml)

Fig. Face Contact-angle meter CA-DT, type-A

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RESULTS AND DISCUSSION

0102030405060708090

100

0 10 20 30 40 50 60 70 80 90 100 110 120

Elapsed time (second)

Con

tact

-ang

le (o )

Ex-H Pf-H Ts-H Ga-H Pm-H Am-HEx-S Pf-S Ts-S Ga-S Pm-S Am-S

Fig. Contact-angle changes within 120s observation time

WETTABILITY

25

22

12

36

83

15

73

146

30

61

14

82

0

20

40

60

80

100

Ex Pf Ts Ga Pm Am

Wood species

Con

tact

-ang

le (

o )Heartwood Sapwood

Fig. Average contact-angle at 20s observation time

WETTABILITY

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WETTABILITY

T. sinensis A. mangium

P. falcataria P. merkusii

Fig. Type of contact-angle at 20s observation time in examples

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CONCLUSIONS

1. Bond strength increased with the increasing of laminated wood density as the same as in solid wood, even though their coefficient of determination (R2) values was lower than those of solid wood.

2. High wood failure for EX, PF, and TS with the density ranges from 0.30 to 0.50g/cm3 showing an indication of good adhesive penetration as compared to GA, PM and AM with the density ranges from 0.51 to 0.70g/cm3.

3. Low wood failure percentages, especially in AM laminates bonded with RF indicated that beside the effect of the density, extractives content of the wood might be interfere with the chemical cure the adhesive.

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CONCLUSIONS

4. Small contact-angle and good wettability were obtained by EX, PF, PM and TS. It is suggested that good wettability resulting good adhesive penetration as shown by high wood failure percentages and resistance to delamination in those wood species. High contact-angle and poor wettability in GM and AM might be causes by deposits of extractives on the wood surfaces.

5. Our continuing study indicated that methanol sweep on the wood surface of AM could reduce the contact-angle and make better wettability as shown by the increasing of wood failure percentage.