Research Journal of Applied Sciences, Engineering and Technology 3(12): 1441-1444, 2011
ISSN: 2040-7467
© Maxwell Scientific Organization, 2011
Submitted: August 08, 2011
Accepted: September 25, 2011
Published: December 26, 2011
Study of Mechanical Properties of Composite Materials Made
from Palm Fruit Fibre and Sawdust
1
1
E.K. Sosu, 1F. Hasford and 2A.B.C. Dadson
Radiological and Medical Science Research Institute, GAEC, Kwabenya, Accra
2
Department of Physics, KNUST, Kumasi
Abstract: To study the possibility of using a composite material made from palm fruit fibre and sawdust as
a building material, the modulus of elasticity, fracture load and the maximum deflection of mahogany sawdust
and palm fruit fibre-kotolyn veneer composites have been determined using the static bending test. The sawdust
particles were sieved into different particle sizes (d): coarse (1.1 mm#d#4.8 mm), medium (0.8 mm#d#1.1
mm) and fine (d#0.8 mm). Briquettes were made from the sawdust of approximately same particle sizes mixed
with palm fibre in different weights proportions, using ‘wood’ glue as a binder. The briquettes were then
sandwiched between two pieces of Kotolyn veneer to form the composites. They were then subjected to
bending tests. The composite materials made from 100wt% of coarse size sawdust recorded the highest fracture
load and modulus of elasticity of 48.00×102 N and 2.23 106 NmG2, respectively. Among the composites
containing both fibre and sawdust, the 90% wt coarse size-10 wt% fibre recorded the highest fracture load and
modulus of elasticity of 30.90×102 N and 1.07×106 NmG2. Mechanical strength of the composite decreased with
decreasing fibre content. The maximum deflection, however, increased with increasing fibre content. The
incorporation of fibre into the sawdust briquettes introduces some degree of flexibility into the composite
materials with a decrease in the strength and doesn’t make good building material but can be used for domestic
finishing’s.
Key words: Briquette, composite, fracture load and fibre, Hooke’s law, Young’s Modulus
INTRODUCTION
Oil Palm (Elaeis guineensis) is the most important
species in Elaeis genus which belongs to the family
Palamae (Teoh, 2002). It is cultivated in West Africa and
in all tropical areas especially in Central and Southern
America. The oil palm fruit is reddish in colour and has a
size of large plum, and grows in large bunches. A bunch
usually has the weight of 40 to 50 kg. Each fruit consists
of a single seed (the palm kernel) and surrounded by a
soft oily pulp mesocarp. Oil is extracted from both the
fruit pulp and the kernel (http://en.wikipedia.org/wiki/
Oil_palm, 2011).
Composite materials can be either natural or artificial
(www.design-technology.org/comp1.htm, 2011). It is a
substance that is made up of a combination of two or
more different materials. A composite material can
provide superior and unique mechanical and physical
properties because it combines the most desirable
properties of its constituents while suppressing their least
desirable. The constituents retain their identities in the
composite; that is, they don’t dissolve or otherwise merge
completely into each other although they act in concert
(DoD, 2002).
The use of natural fibers to re-inforce building
material can be traced back to Egyptian times when
straws or horsehair were added to mud bricks (Aziz et el.,
1984). In Ghana, oil palm industries (Palm Oil producing
companies, Soap Production Company’s and restaurants)
have left a huge amount of residues mainly in the form of
fibers that can be readily turned into useful value added
products. Oil palm fiber is a unique reinforcing material
as it is non-hazardous, renewable, and readily available at
no cost. To date only a small percentage of these residues
are turned into useful products and the rest is either left to
rot or worst, burnt and polluting the environment (Roslan
et al., 2011).
In this study, sawdust from wood shaving is reinforce with palm fruit fiber, to develop value-added
biomaterials for the construction industry.
MATERIALS AND METHODS
Materials used in this project were briquettes
prepared from well-dried mahogany sawdust, washed and
well-dried palm fruit fibre, using wood glue as binding
agent. It also consisted of a wooden mould of internal
dimension s 30 cm × 4 cm × 1.91 cm, two bowls,
Corresponding Author: E.K. Sosu, Radiological and Medical Science Research Institute, GAEC, Kwabenya, Accra
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Res. J. Appl. Sci. Eng. Technol., 3(12): 1441-1444, 2011
Table1: Different particles sizes of sawdust
Sample
Particle size
A
d#0.8 mm (fine size)
B
0.8 mm # d # 1.1 mm (medium size)
C
1.1 mm # d # 4.8 mm (coarse size)
Hooke described this behaviour and it is expressed
mathematically as:
Table 2: Different proportion for aggregates of different particle sizes
Sample type
-------------------------------------Coarse
Medium Fine
Sawdust Sawdust Sawdust Type Sawdust/g Palm fruit fibre/g
A
G
M
10
90
B
H
N
30
70
C
I
O
50
50
D
J
P
70
30
E
K
Q
90
10
F
L
R
100
0
x
F = Kx
F
k
electronic balance, a measuring can and sieves of different
sizes (Table 1).
The samples were prepared at the Physics
Department and tested at the Mechanical Engineering
Department both of Kwame Nkrumah University of
Science and Technology, Kumasi, Ghana between
December 2002 and April 2003.
Preparation of samples: Sawdust from mahogany log
was collected from a carpentry workshop. It was then
dried for almost two weeks in the sun in order to reduce
the moisture content. The sawdust was then sieved into
three different particle sizes in order of increasing of
opening. The palm fruit fibre was also obtained from a
local restaurant in the community. The palm fruit fibre
was treated with warm water and soap after which it was
dried. The process was carried out for almost three weeks
in order to reduce to a large extent the oil content of the
fibre.
Briquette formation: Sawdust of different particle sizes
i.e. fine, medium and coarse was weighed. The fibre was
also weighed and both were poured into a bowl. The
wood glue was added to the contents of the bowl and
mixed thoroughly and the briquette was formed by
transferring the mixture into the mould. A total of
eighteen (18) briquettes was made, six (6) briquettes was
made for each sawdust particle size.
Formation of composites: Single-ply composite slabs
were formed by sandwiching one dry briquette into twokotolyn veneer cut to the dimension of the briquette (30
cm × 4 cm × 1.91 cm). Using wood glue as a binder,
pressure was exerted to ensure good bonding of the
pieces.
Determination of moduli of elasticity, fracture load
and maximum deflection: When strain is small in a
material, it produces a stress which is proportional to the
applied stress. Also if the strain is small, it’s fully
recoverable if the time of application of the stress is short.
is the displacement of the spring's end from its
equilibrium position (a distance, in SI units: meters)
is the restoring force exerted by the spring on that
end (in SI units: N or kgm/s2)
is a constant (in SI units: N/m or N/m2 or kg/s2)
The proportionality constant, (k), relating these two
terms is called the Modulus of Elasticity. The Modulus of
elasticity for compressive and tensile stresses is known as
Young’s Modulus denoted by E.
Calculation: Young's modulus, E, can be calculated by
dividing the tensile stress by the tensile strain in the
elastic (initial, linear) portion of the stress-strain curve:
E
tensile stress 
F / A0
FL0



tensile strain 
A0 / 
A0 L
where.
E is the Young's modulus (modulus of elasticity)
F is the force applied to the object
A0 is the original cross-sectional area through which the
force is applied
)L is the amount by which the length of the object
changes
L0 is the original length of the object
Force exerted by stretched or compressed material:
The Young's modulus of a material can be used to
calculate the force it exerts under specific strain:
F
EA0  L
L0
where, F is the force exerted by the material when
compressed or stretched by )L.
Hooke's law can be derived from this formula, which
describes the stiffness of an ideal spring:
 EA0 
F
  L  kx
 L0 
where, k 
EA0
, x  L
L0
Each sample was placed on two supports fixed at a
distance of 20 cm apart. Loads in steps of 1.8 N were
initially hanged at the center of the sample and the
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Res. J. Appl. Sci. Eng. Technol., 3(12): 1441-1444, 2011
200
150
E
100
C
A
D
B
50
0
20
0
100
80
60
%WT Coarse sawdust
120
L
-4
K
I
H
5
0
100
80
60
%WT Medium sawdust
120
20
100
120
A
120
B
C
D
E
80
F
60
40
20
0
30
80
60
%WT Coarse sawdust
0
Fig. 2: A graph of Youngs Modulus against % weight of
medium sawdust
20
40
60
%Coarse sawdust
80
100
Fig. 5: A graph of maximum deflection against % weight of
coarse sawdust
R
25
4
Youngs modulus x10 N/m 2
50
100
J
20
100
140
25
0
150
Fig. 4: A graph of Youngs Modulus against % weight of
sawdust
Maximum deflection x10 m
4
Youngs modulus x10 N/m2
35
G
Fine sawdust and fiber samples
0
30
15
Medium sawdust and fiber samples
200
0
Fig. 1: A graph of Young’s Modulus against % weight of
coarse sawdust
20
Coarse sawdust and fiber samples
250
F
Youngs modulus x104 N/m 2
Youngs modulus x104 N/m 2
250
20
Q
15
P
O
M
N
5
0
0
20
80
60
%WT Fine sawdust
100
120
Fig. 3: A graph of Youngs Modulus against % weight of fine
sawdust
corresponding deflections were measured with a dial
gauge. Secondly the weights were loaded in steps of 2.25
N for samples that could not fracture by the end of the
loads of 1.8 N. Some samples which were very strong and
firm did not fracture at all so loads in steps of 9N were
loaded. Each of the samples was loaded to failure. The
fracture load and the maximum deflection were recorded.
Graphs of load versus deflection were plotted and the
Moduli of Elasticity computed within the elastic region of
the curves.
RESULTS AND DISCUSSION
From Fig. 1 to 3, it was observed that as the sawdust
content in the composite material increased, the Young’s
Modulus generally increased. There was, however an
initial decrease in the Young’s Modulus from the
composite material containing 10 g of sawdust and 90 g
of palm fruit fibre to the sample containing 30 g of
sawdust and 70 g of palm fruit fibre. This can be
attributed to the high content of the palm fruit fibre in the
composite material. The property of the palm fruit fibre
which was being exhibited was the elastic nature of the
fibre. So that as the fibre content in the composite
material decreased, the Young’s Modulus increased. After
that there was a continual increase in the Young’s
Modulus up to the material containing 100 g of sawdust
which recorded the highest value.
From Fig. 4, it was observed that as the sawdust
contents of the composite material increased, there was a
general increase in the Young’s Modulus for all three sets
of samples. For the composite material containing 50 g
sawdust and 50 g palm fruit fibre; the coarse sample
records a maximum deflection of about 75×104 N/m2; the
medium sample records a maximum deflection of about
10×104 N/m2 ; the fine samples records a maximum
deflection of about 4×104 N/m2. So that as oung’s
Modulus increased. The coarse sawdust and palm fruit
composite materials recorded the highest Young’s
Modulus values.
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Res. J. Appl. Sci. Eng. Technol., 3(12): 1441-1444, 2011
-4
Maximum deflection x10 m
600
G
H
500
400
I
300
J
K
200
L
100
0
0
20
40
60
80
%Medium sawdust
100
120
Fig. 6: A graph of Maximum deflection against % weight of
medium sawdust
general decrease in the maximum deflection for all three
sets of samples. For the composite material containing 50
g sawdust and 50 g of palm fruit fibre; the coarse sample
records a maximum deflection of about 100×10G4m; the
medium sample records a maximum deflection of about
300×10G4 m; the fine sample records a maximum
deflection of about 700×10G4 m. The fine sawdust/fibre
samples, recorded the highest maximum deflection due to
the stronger bond between the particles. So that as the
sawdust content increased the strength of the composite
material increased and hence the maximum deflection
decreased.
CONCLUSION
M
-4
Maximum deflection x10 m
800
N
700
600
The major results of this work show the following:
• Young’s Modulus increased as the sawdust increased
and the palm fruit fibre decreased in the composite
material.
• Fracture load increased as the sawdust increased and
the palm fruit fibre decreased in the composite
material.
• Maximum deflection decreased with an increase in
the sawdust content, it however increased with the
increase in palm fruit fibre.
O
500
P
400
Q
300
R
200
100
0
0
20
40
60
%Fine sawdust
80
100
120
Youngs modulus x104 N/m 2
Fig. 7: A graph of Maximum deflection against % weight of
fine sawdust.
Coarse sawdust and fiber samples
Medium sawdust and fiber samples
Fine sawdust and fiber samples
900
800
700
600
500
400
300
200
100
0
0
20
60
80
%WT Coarse sawdust
100
120
Fig. 8: A graph of Maximum deflection against % weight of
sawdust
From Fig. 5 to 7, it was observed that as the sawdust
content in the composite material increased, the maximum
deflection on the dial gauge decreased, this can be
attributed to the increase in strength of the sample as the
sawdust content increased. So that there was a general
decrease in the maximum deflection as the sawdust
increased in the composite material.
From Fig. 8 is was established that as the sawdust
content of the composite material increased, there was a
REFERENCES
Aziz, M.A, P. Paramasivam and S.L. Lee, 1984. Concrete
reinforced with natural fibres. Concrete Technology
and Design, New Reinforced Concretes. Surrey
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Department of Defence (DoD), 2002. Composite
Materials Handbook. 3: 35. (MIL-HDBK-17-3F).
Retrieved from: www.lib.ucdavis.edu/dept/pse/
resources/fulltext/HDBK17-3F.pdf, (Accessed on:
August 2011) .
Roslan, K., W.I.M. Haziman and J.W. Eng, 2011.
Properties of Cement Blocks Containing high
Content of Oil Palm Empty Fruit Bunches (EFB)
fibres. Faculty of Civil & Environmental
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http://eprints.uthm.edu.my/270/1/roslan-kolop.pdf.
Teoh, C.H., 2002. The Palm oil industry in Malaysia.
Retrieved from: http://asest.panda.org/download/
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http://en.wikipedia.org/wiki/Oil-palm.
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