The Effect of Gambir Adhesive Level and Hot Press Temperature on
Physical and Mechanical Properties of Bamboo Particleboard
Tito Sucipto
1
, Ragil Widyorini
2
, Tibertius Agus Prayitno
2
and Ganis Lukmandaru
2
1
Department of Forest Product Technology, Faculty of Forestry, Universitas Sumatera Utara,
Jl. Tri Dharma Ujung No.1 Medan20155, Indonesia
2
Department of Forest Product Technology, Faculty of Forestry, Universitas Gadjah Mada,
Jl. Agro No.1 Yogyakarta55281, Indonesia
Keywords: Gambir, Adhesive, Bamboo, Particleboard, Properties.
Abstract: Gambir is the extract of leaves sap and young twigs of gambir plants, which contains tannin.Gambir-
formaldehyde adhesives have been applied to the particleboards, butsome properties of particleboard
produced did not meetthe standard.In this study, gambir adhesives (without formaldehyde) were applied to
the bamboo particleboard.The dimension of particleboard was 25x25x1 cm, and the board density target was
set at 0.8 g/cm3. Three kinds of adhesive levels (10, 20, 30%) and four kinds of hot-press temperature (160,
180, 200, 220
o
C) were used for particleboard production. The research aimed to investigatethe effect of
gambir adhesive level and hot-press temperature on the physical and mechanical properties of the
bambooparticleboard. The physical and mechanical properties of particleboards were then evaluated and
compared to the JIS A5908-2003 standard.The study showed that adhesive level and hot-press temperature
affected significantly on thickness swelling, water absorption, internal bond, modulus of rupture and modulus
of elasticityof particleboard, while the effect of an adhesive level factor was also significant on density
properties.Interaction between adhesive level and hot-press temperature factor only affected significantly on
water absorption. Particleboards with hot-press temperatures of 200
o
C and 220
o
C have better properties than
others.The high hot-press temperature has exceeded the melting point of the catechin (174-178
o
C),
furthermore, the gambir adhesive becomes hardened and cured. The most optimal bamboo particleboard is
particleboard with 220
o
C hot-press temperature and adhesive level of 30%, based on the best of particleboard
properties compared to JIS A5908-2003.
1 INTRODUCTION
Gambir (Uncariagambir (Hunter) Roxb.) in
Indonesia are mostly found in West Sumatra and Riau
Province (export markets), as well as North Sumatra,
Bengkulu, South Sumatra and Aceh (local markets)
(Sabarni, 2015; Gumbira-Sa’idet al., 2009). In 2012,
gambir commodities in Indonesia with gambir plant
area covering 29,326 ha could produce 20,511 tons of
dried gambir and exported as many as 15,685 tons
worth US$ 34 million(Ministry of Agriculture of
Indonesia, 2013).
Gambir is the extract of leaves sap and young
twigs of gambir plants, which contain tannin
especially tannin from catechins of phenolic groups.
Some gambir extract products are processed by the
community in various gambir production center in
Indonesia. It hasthe catechin content varies from 2.5
to 95% (Amos, 2010).
Many national and global industries need gambir
as the main or additional materials in the production
process. The factories include the chemical industry,
biopharmaceuticals, cosmetics, textiles, leather
processing, food and beverages, biopesticides, and
metal industries (Ministry of Agriculture of
Indonesia, 2013).
The tannins in gambir can also be used as natural
adhesives (Pizzi, 1994; Pizzi, 2008).Gambir
adhesives combined with formaldehyde have been
applied to particleboards from oil palm trunk (Kasim
et al., 2007), empty fruit bunches mixture with acacia
bark (Fathanah and Sofyana, 2013), and empty fruit
bunches (Junaidiet al., 2015).Formaldehyde
functions as a cross-linker or hardener, with additions
of 10% (Kasim et al., 2007; Junaidiet al., 2015) and
362
Sucipto, T., Widyorini, R., Prayitno, T. and Lukmandaru, G.
The Effect of Gambir Adhesive Level and Hot Press Temperature on Physical and Mechanical Properties of Bamboo Particleboard.
DOI: 10.5220/0010182800002775
In Proceedings of the 1st International MIPAnet Conference on Science and Mathematics (IMC-SciMath 2019), pages 362-367
ISBN: 978-989-758-556-2
Copyright
c
 2022 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved

2% (Fathanah and Sofyana, 2013). However, on the
other hand, formaldehyde causes formaldehyde
emissions, that are toxic and can disrupt the
environment and humans (Foyer et al., 2016).
Some physical and mechanical properties of the
produced particleboard (Kasim et al., 2007; Fathanah
and Sofyana, 2013; Junaidiet al., 2015)did not meet
the particleboard standards based on SNI 03-2105-
2006. This is thought to be caused by the weakness of
material preparation, gambir adhesive formulation,
and hot-press process, therefore that the bonding
between adhesive and lignocellulose particles was not
optimal.
The adhesive level and hot-press temperature
affect the quality of the particleboard. As a factor
affecting particle board quality, the levels of gambir-
formaldehyde adhesives that have been used were
16% (Kasim et al., 2007), 12%, 14%, 16% (Junaidiet
al., 2015), and the ratio of gambir to empty fruit
bunches (v/v) 30/70, 40/60, 50/50, 60/40 and 70/30
(Fathanah and Sofyana, 2013). The optimal hot-press
temperature was 150
o
C for 15 min (Kasim et al.,
2007; Junaidiet al., 2015) and 145
o
C for 30 min
(Fathanah and Sofyana, 2013). The particleboard hot-
press temperature was less optimal because it is lower
than the melting point of the catechin as the main
component of the gambir. The melting point of
catechins was 174-178
o
C (Rahmawatiet al., 2012).
This means that the gambir adhesive was thought to
have not melted to subsequently harden when
bonding with lignocellulose particles.
Based on these problems, gambir adhesives
(without formaldehyde) were applied to the bamboo
particleboard by a factor of adhesive level and hot-
press temperature. Betung bamboo wastes from the
industry of roof truss components were used as
particle materials. Particleboards were tested for the
physical and mechanical properties based on JIS
A5908-2003 standards. The study aimedto
investigate the effect of gambir adhesive level and
hot-press temperature on the physical and mechanical
properties of bamboo particleboard.
2 MATERIALS AND METHODS
2.1 Materials
Gambirwas purchased from the traditional market
and sodium hydroxide (97%) was purchased from
Merck. Gambir commonly called gambirbootch,
cylindrical form, and dark brown color were used
without purification. Each gambir and sodium
hydroxide were ground into powder (passes 20-mesh
screen).
Betung bamboo (Dendrocalamus asper) was used
as a particleboard material, originating from the
industrial waste of roof truss component in Sleman
District, Special Region of Yogyakarta. Bamboo chip
wasground into a particle (passes 10-mesh screen)
and dried to air-dry condition.
2.2 Methods
2.2.1 Adhesive Formulation
The gambir adhesives were made by dissolving
gambir powder in distilled water. The concentration
of the solution was adjusted to 45wt%. In each
gambir adhesive formulation, the sodium hydroxide
solution was added until pH 8 was reached (Kasim et
al., 2007).
2.2.2 Particleboard Manufacturing
The particleboard manufacturing consisted of
blending, particles and adhesives mix drying at 80
o
C
for 4 hours, mat-forming, hot-pressing, and
conditioning for one week. The dimension of
particleboard was 25x25x1 cm, and the board density
target was set at 0.8 g/cm
3
. Four kinds of hot-press
temperature (160
o
C, 180
o
C, 200
o
C, 220
o
C) and three
kinds of adhesive levels (10%, 20%, 30%) were used
for particleboard production.
The boards were pressed at four kinds of
temperaturewith a pressure of 3.5 MPa for 10
min.Particleboard pressing used the breathing system
(5-1-5 min). The particleboard was then conditioned
at room temperature for one week. The gambir
adhesives and bamboo particle preparation are
summarized in Table 1.
2.2.3 Particleboards Testing
The particleboards were cut into a sample for physical
and mechanical properties testing. The sample size
used of 5x5 cm (thickness swelling, water absorption,
density, and internal bond testing), and 20x5 cm
(modulus of rupture and modulus of elasticity
testing).
The physical properties of particleboards
(thickness swelling, water absorption, and density)
and mechanical properties (internal bond, modulus of
rupture, and modulus of elasticity) were then
evaluated. The board properties were compared to the
JIS A5908-2003 standard. The effect of adhesive
level and hot-press temperature on the particleboard
properties were tested by statistical variance analysis.
The Effect of Gambir Adhesive Level and Hot Press Temperature on Physical and Mechanical Properties of Bamboo Particleboard
363

Table 1: Preparation of gambir and bamboo particle.
Hot-press
temperature
(
o
C)
Adhesive level (%) Gambir (g) Distilled water (ml) NaOH 50% (ml) Bamboo particle (g)
160
10 45.45 101.00 8 504.54
20 83.33 185.18 14 462.49
30 115.38 256.40 19 426.93
180
10 45.45 101.00 8 504.54
20 83.33 185.18 14 462.49
30 115.38 256.40 19 426.93
200
10 45.45 101.00 8 504.54
20 83.33 185.18 14 462.49
30 115.38 256.40 19 426.93
220
10 45.45 101.00 8 504.54
20 83.33 185.18 14 462.49
30 115.38 256.40 19 426.93
3 RESULTS AND DISCUSSIONS
3.1 Physical Properties
The thickness swelling of bamboo particleboard
ranged from 13.11% to 131.70%. Figure 1 showed
that all the thickness swelling of particleboard did not
meet the requirement of JIS A5908-2003 (≤12% of
thickness swelling).
Figure 1: Thickness swelling of particleboard.
In another study, the thickness swelling of
bamboo binderless particleboard was below than
12%, to meet the requirement of JIS A5908-2003.The
binderless particleboard was hot-pressed on 200
o
C
temperature for 15 min (Widyoriniet al., 2011). It
might be due to the polar characteristic of gambir
tannins (10% to 30%) was applied in this study and a
difference in the target of density (0.8 g/cm
3
vs 0.9
g/cm
3
). It was reported that catechin is the main
chemical component of gambir (Amos, 2010; Hiller
and Melzig, 2007).
The factors of adhesive level and hot-press
temperature significantly affected the board thickness
swelling, while the interaction between two factors
was not significant. The high level ofhot-press
temperature with the high adhesive level formed a
strong bonding between gambir adhesive and bamboo
particles.
The particleboard of oil palm trunk used gambir-
formaldehyde adhesive obtained thickness swelling
properties ranged from 56.98% to 72.63% (Kasim et
al., 2007). Consequently, no formaldehyde addition
as hardener or cross-linker on gambir adhesive.
The average of particleboard water absorption
was 114.34% (Figure 2). Water absorption is usually
in line with the thickness swelling, therefore the lower
of adhesive level and hot-press temperature will
increase the water absorption and thickness swelling
properties.
The water absorption of particleboards that meets
the FAO standard are particleboards with a hot-press
temperature of 220
o
C (all adhesive level) and 200
o
C
hot-press temperature on adhesive level of 20% and
30%. FAO standards require the particleboard water
absorption ranged from 20% to 75%. The factors of
adhesive level and hot-press temperature and
interaction between two factors were significantly
affected on the board water absorption.
0
20
40
60
80
100
120
140
160
160180200220
T hickness swell ing (% )
H ot- pr ess t emper at ur e (
o
C)
10% 20% 30%
IMC-SciMath 2019 - The International MIPAnet Conference on Science and Mathematics (IMC-SciMath)
364

Figure 2: Water absorptionof particleboard.
Figure 3 showed that all the density of
particleboardswere ranged from 0.74 g/cm
3
to 0.83
g/cm
3
(average of 0.80 g/cm
3
), meet the JIS A5908-
2003 requirement.
Figure 3: Density of particleboard.
The particleboard density wasappropriated to the
density target of 0.80 g/cm
3
and classified to the
medium density particleboard group (0.59-0.80
g/cm
3
) (Maloney, 1993). The factors of adhesive level
significantly affected the board density, while hot-
press temperature factor and interaction between two
factors were not significant. Other studies showed
that density of particleboard ranged from 0.60g/cm
3
to 0.75 g/cm
3
(density target of 0.7 g/cm
3
) (Kasim,
2007) and 0.75-0.85 g/cm
3
(density target of
0.9g/cm
3
) (Widyoriniet al., 2011).
3.2 Mechanical Properties
The effect of adhesive level and hot-press
temperature on internal bond, modulus of rupture and
modulus of elasticity of bamboo particleboard are
shown in Figure 4, Figure 5, and Figure 6,
respectively. The internal bond of bamboo
particleboard ranged from 0.03 MPa to 0.70 MPa.
The result showed that the internal bond of
bamboo particleboard waslower than the internal
bond of oil palm trunk particleboard used gambir-
formaldehyde adhesive (0,71-0,81 MPa) (Kasim et
al., 2007). Formaldehyde as a cross-linker on gambir
adhesive could increase the internal bond of
particleboard, even though itcauses toxic emissions
for the environment and humans (Foyer et al., 2016).
Figure 4: Internal bond of particleboard.
The factors of adhesive level and hot-press
temperature significantly affected the board internal
bond, while the interaction between two factors was
not significant. The result showed that internal bond
values meet JIS A5908-2003 requirement for grade 8
types particleboard, on particleboard with the
adhesive level of 20% and 30% (all hot-press
temperature), plus an adhesive level of 10% (220
o
C).
Particleboards with a hot-press temperature of 200
and 220
o
C (adhesive level of 20% and 30%) also meet
JIS A5908-2003 (type 18).
The modulus of rupture of bamboo particleboard
ranged from 3.13MPa to 14.16MPa (Figure 5).
Figure 5: Modulus of rupture of particleboard.
The interaction between two factors was not
significantly affected the board modulus of rupture,
while the factors of adhesive level and hot-press
0
50
100
150
200
250
300
160 180 200 220
Water absorption (% )
H ot-pr ess t emper at ur e (
o
C)
10% 20% 30%
0,0
0,2
0,4
0,6
0,8
1,0
160 180 200 220
Density (g/cm
3
)
H ot-pr ess t emper at ur e (
o
C)
10% 20% 30%
0,0
0,2
0,4
0,6
0,8
1,0
160180200220
Internal bond (MPa)
H ot-pr ess t emper at ur e (
o
C)
10% 20% 30%
0
2
4
6
8
10
12
14
16
18
160 180 200 220
M odulus of rupture (M Pa)
H ot-pr ess t emper at ur e (
o
C)
10% 20% 30%
The Effect of Gambir Adhesive Level and Hot Press Temperature on Physical and Mechanical Properties of Bamboo Particleboard
365

temperature significantly affected the modulus of
rupture properties. Particleboards with all hot-press
temperature (adhesive level of 20% and 30%) were
met JIS A5908-2003 (type 8). Particleboard grade 13
type only fulfilled by particleboards with hot press
temperature of 220
o
C (adhesive level of 20% and
30%).
Figure 6 showed that the modulus of elasticity of
bamboo particleboard ranged from 0.68 GPa to 3.21
GPa (average of 2.24 GPa).
Figure 6: Modulus of elasticity of particleboard.
Particleboard that meets JIS A5908-2003 (type 8)
requirement for modulus of elasticity were all
particleboard with the adhesive level of 20% and
30%, plus one particleboard with the adhesive level
of 10% on 220
o
C hot-press temperature.
For JIS A5908-2003 (type 8)fulfilled by
particleboards with a hot-press temperature of 200
and 220
o
C (adhesive level of 20% and 30%).The one
and only particleboard with a hot-press temperature
of 200
o
C on adhesive level of 30%were meet JIS
A5908-2003 (type 18).
The factors of adhesive level and hot-press
temperature significantly affected the board modulus
of elasticity, while the interaction between two
factors was not significant.
3.3 The Optimal Physical and
Mechanical Properties of
Particleboards
The physical and mechanical properties of bamboo
particleboards compared with JIS A5908-2003 and
statistical analysis are summarized in Table 2. The
most optimal bamboo particleboard is particleboard
with 220
o
C hot-press temperature and adhesive level
of 30%, based on the best values of the physical and
mechanical properties of particleboard compared to
JIS A5908-2003.
Table 2: The physical and mechanical properties of particleboards compared with JIS A5908-2003 and statistical analysis.
Hot-press
temperature
(
o
C)
Adhesive
level (%)
Physical properties Mechanical properties
TS (%) WA (%) D (g/cm
3
) IB (MPa) MOR (MPa) MOE (GPa)
160
10 131.70 (a) 250.29 (a) 0.74
)18
(c) 0.03 (d) 3.19 (e) 0.68 (e)
20 103.66 (b) 173.33 (bc) 0.82
)18
(a) 0.28
)13
(bcd) 10.24
)8
(abc) 2.35
)8
(abc)
30 89.10 (b) 154.05 (c) 0.81
)18
(ab) 0.20
)13
(cd) 9.05
)8
(abcd) 2.48
)8
(abc)
180
10 101.79 (b) 184.96 (b) 0.76
)18
(bc) 0.07 (cd) 4.95 (de) 1.12 (de)
20 63.58 (c) 109.40 (d) 0.82
)18
(a) 0.27
)13
(bcd) 9.71
)8
(abcd) 2.47
)8
(abc)
30 54.69 (c) 104.98 (d) 0.80
)18
(ab) 0.17
)8
(cd) 8.88
)8
(abcd) 2.40
)8
(abc)
200
10 59.38 (c) 108.87 (d) 0.80
)18
(ab) 0.09 (cd) 6.55 (cde) 1.60 (cd)
20 31.20 (d) 66.35 (e) 0.83
)18
(a) 0.33
)18
(bcd) 12.17
)8
(ab) 2.87
)13
(ab)
30 25.85 (d) 59.06 (e) 0.83
)18
(a) 0.38
)18
(bc) 12.49
)8
(ab) 3.21
)18
(a)
220
10 24.78 (d) 57.09 (e) 0.80
)18
(ab) 0.22
)13
(bcd) 7.70 (bcde) 2.07
)8
(bc)
20 13.31 (d) 41.36 (e) 0.82
)18
(a) 0.51
)18
(ab) 13.45
)13
(a) 2.81
)13
(ab)
30 13.11 (d) 38.82 (e) 0.80
)18
(ab) 0.70
)18
(a) 14.16
)13
(ab) 2.86
)13
(ab)
JIS A5908-
2003
Type 8
≤12 20-75* 0.4–0.9
≥0.15 ≥8 ≥2
Type 13 ≥0.2 ≥13 ≥2.5
Type 18 ≥0.3 ≥18 ≥3
Description: - *FAO standard.
-
)8
meet JIS A5908-2003 type 8;
)13
meet JIS A5908-2003 type 13;
)18
meet JIS A5908-2003 type 18.
- numbers followed by the same letters (in parentheses) mean that they are not significantly different.
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
160 180 200 220
M odulus of elasticity (GPa)
Hot-press temperature (
o
C)
10% 20% 30%
IMC-SciMath 2019 - The International MIPAnet Conference on Science and Mathematics (IMC-SciMath)
366

4 CONCLUSIONS
 Gambir could be used as the natural adhesive for
particleboard, that can meet most of the JIS
A5908-2003 requirements. Adhesive level and
hot-press temperature factor affected significantly
on thickness swelling, water absorption, internal
bond, modulus of rupture and modulus of
elasticity of particleboard, whilethe effect of an
adhesive level factor was also significant on the
density of particleboard.Interaction between
adhesive level and hot press temperature factor
only affected significantly on water absorption of
particleboard.
 Particleboards with hot-press temperatures of
200
o
C and 220
o
C have better properties than
others. Particleboards with the adhesive level of
20% and 30% also have better properties than
10%.The high hot-press temperature has
exceeded the melting point of the catechin (174-
178
o
C), therefore the gambir adhesive becomes
hardened and cured. The most optimal bamboo
particleboard is particleboard with 220
o
C hot-
press temperature and adhesive level of 30%,
based on the best of particleboard properties
compared to JIS A5908-2003.
ACKNOWLEDGMENTS
The authors are grateful for the financial support from
The Indonesia Endowment Fund for Education
(LPDP) and The Ministry of Research, Technology,
and Higher Education of Indonesia.
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The Effect of Gambir Adhesive Level and Hot Press Temperature on Physical and Mechanical Properties of Bamboo Particleboard
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