Journal of Minerals and Materials Characterization and Engineering, 2012, 11, 780-784
Published Online August 2012 (
Assessing Mechanical Properties of Natural Fibre
Reinforced Composites for Engineering Applications
Olusegun David Samuel1*, Stephen Agbo2, Timothy Adesoye Adekanye3
1Department of Mechanical Engineering, Olabisi Onabanjo University, Ago-Iwoye, Nigeria
2Department of Mechanical Engineering, Lagos City Polytechnic, Ikeja, Nigeria
3Department of Agricultural Engineering, Landmark University, Omuaran, Nigeria
Email: *,
Received March 4, 2012; revised April 20, 2012; accepted May 15, 2012
Mechanical properties of ukam, banana, sisal, coconut, hemp and E-glass fibre reinforced laminates were evaluated to
assess the possibility of using it as new material in engineering applications. Samples were fabricated by the hand
lay-up process (30:70 fibre and matrix ratio by weight) and the properties evaluated using the INSTRON material test-
ing system. The mechanical properties were tested and showed that glass laminate has the maximum tensile strength of
63 MPa, bending strength of 0.5 MPa, compressive strength of 37.75 MPa and the impact strength of 17.82 J/m2. The
ukam plant fibre laminate has the maximum tensile strength of 16.25 MPa and the impact strength of 9.8J/m among the
natural fibres; the sisal laminate has the maximum compressive strength of 42 MPa and maximum bending strength of
0.0036 MPa among the natural fibres. Results indicated that natural fibres are of interest for low-cost engineering ap-
plications and can compete with artificial glass fibres (E-glass fibre) when a high stiffness per unit weight is desirable.
Results also indicated that future research towards significant improvements in tensile and impact strength of these
types of composites should focus on the optimisation of fibre strength rather than interfacial bond strength.
Keywords: Reinforced Laminates; Hand Lay-Up Method; E-Glass Fibre Reinforced; Natural Fibre
1. Introduction
Research and development of natural fibres as rein-
forcement for automotive sectors is a growing interest to
scientists and engineers. Nowadays, natural fibres form is
an interesting option for the most widely applied fibre in
the composite technology. Many studies on natural stud-
ies such as keraf, bagasse, jute, ramie, hemp and oil palm
[1-9]. Fibre reinforced composites with thermoplastic
matrices have successfully proven their high qualities in
various fields of engineering application. However,
Natural fibres generally have poor mechanical properties
compared with synthetic fibres but these composites
were used as a source of energy to make shelters, clothes,
construction of weapons [10]. High cost of synthetic fi-
bres and health hazards of abestors fibres have really
necessitated the exploration of natural fibres [11]. Con-
sequently, natural fibres have always formed wide appli-
cations from the time they gained commercial recogni-
tion. They possess desirable properties such as biode-
grability, renewability, combustibility, lower durability,
excellent mechanical properties, low density and low
price. Stamboulis and Baley [12] reported that this excel-
lent price-performance ratio at low weight in combina-
tion with the environmentally friendly character is very
important for the acceptance of natural fibres in large
volume engineering markets, such as the automotive and
construction industries.
Since the beginning of human existence, people have
developed plant fiber composites. Brahmakumar et al.
[13] reported that these composites were used as a source
of energy to make shelters, clothes, construction of
weapons. The use of fibres as cloth was centered largely
in the country side, with higher quality textiles being
available in the towns. In late medieval Germany and
Italy, fibres were employed in cooked dishes, as fillers in
pies and boiled soup.
A composite may be defined as a physical mixture of
two or more different materials. The mixture has proper-
ties which are generally better than those of any one of
the materials. It is necessary to use combinations of ma-
terials to solve problems because any one material alone
cannot do so at an acceptable cost or performance. These
composites were produced in simple shapes and easy
design structures by positioning the structural elements
on top of each other to create the desired design.
*Corresponding author. Strength of glass fibre reinforced composites depends
Copyright © 2012 SciRes. JMMCE
not only on the properties of the components but also on
the mechanism of composite failure which is a function
of how well the composite was formed [14].
Oladele et al. [15] reported that the fibre/matrix has an
important role in the micromechanical behaviour of
composite. Lack of good adhesion with the polymeric
matrix, and large moisture absorption of natural fibres
adversely affe ct adhesion with h ydrophobic matrix mate-
rial .These problems often lead to premature ageing by
degrading and l oss of strength.
Natural fibre-reinforced composites have been increas-
ingly utilized in quite widespread applications. Natural
fibres are obtained from different parts of the plants, to
name a few, for example jute, flax, kenaf, coconut, hemp,
ukam, sisal, banana, pineapple fibres from the leaf; cot-
ton and kapok from seed; coir and coconut from the fruit.
For example hemp, jute, flax and sisal fibres are already
used in automotive indu stry [16].
In polymeric composite terms, natural fibre reinforce-
ment is a manufactured assembly of long or short bun-
dles of natural fibres to produce a flat sheet or mat of one
or more layers of fibres. These layers are held together
either by mechanical interlocking of the fibres them-
selves or with a binder to hold these materials together
giving the assembly sufficient integrity to be handled.
The un-reinforced plastics have low density, are rela-
tively easy to process, resistant to weathering and do not
require a surface finish.
The components of natural fibres are cellulose, hemi-
cellulose, lignin, pectin, waxes and water soluble sub-
stances. The cellulose, hemicellulose and lignin are the
basic components of natural fibres, governing the physi-
cal properties of the fibres [17]. In order to fully utilize
the natural fibres, understanding their physical and me-
chanical properties is vital. A unique characteristic of
natural fibres is depended upon the variations in the
characteristics and amount of these components, as well
as difference in its cellular structure. Therefore, to use
natural fibres to its best advantages and most effectively
in automotive and industrial application, physical and
mechanical properties of natural fibres must be consid-
ered. Many studies have investigated the properties of
natural fibres. Numerous researchers have studied me-
chanical properties of varied natural fibres [18]. Tradi-
tionally, natural fibres are used and known for rope,
twine, and course sacking materials; and they are biode-
gradable and environmentally friendly crop. All men-
tioned studies have assisted engineers with the design
and efficient usage of the natural fibres. However, the
fibers modification is required and needed to improve
mechanical properties for composites product. Efficiency
of the fiber-reinforced composites also depends on the
manufacturing process that the ability to transfer stress
from the matrix to fiber [19]. In this study, natural fibre
laminated laminates were made by hand lay-up method
and their mechanical properties were investigated in or-
der to assess its suitability.
2. Material and Methods
2.1. Materials and Equipment
The composite materials used in the production of the
specimens include: E-glass fibre (artificial fibres) ukam
plant, resin, fibres, wax, release agent, gel coat and mis-
cellaneous items. The equipment used are weighing bal-
ance, cloth, stirrers, measuring cylinder, universal testing
2.2. Fibre Treatment
In this study, chemical resetting was used. The procedure
involves NaOH solution treatment, water washing and
drying. Natural fibres are extracted from their parent
plant. The ukam, sisal and banana are extracted from the
back of their stems, while hemp and coconut are ex-
tracted from their fruits. The natural fibres, after being
extracted, are washed with water to remove gums. The
fibres are then treated with sodium hydroxide solution
and rammed. The treated fibre was allowed to dry in the
sun for 3 days. After which the fibres are laid in the mold
with the resin at the ratio of 30% to 70%. It was allowed
to cure for about 20 days.
2.3. Laminate Manufacture’s Methods
In this study, samples of laminates were made by using
hand lay-up method. The method used in this study was
employed due to its simplicity and availability of the
items. Details of the procedures taken in the production
of laminates via hand lay-up method are elsewhere dis-
cussed (Agbo, 2009).
2.4. Measurement
2.4.1. Tensile Test
The tensile tests were performed using a testin g machine
model 8889. The width and the thickness of the speci-
mens were measured and recorded (360 mm by 20 mm
by 5 mm). The tensile tests were carried out according to
ASTM D 038-01. The tensile strengths were calculated
from this test.
2.4.2. Bending Test
Three point bending tests were performed using a testing
machine in accordance to ASTM D 790 standards. For
the bending test, samples with dimensions of 300 mm ×
20 mm × 5 mm were used. The bending strength test was
carried out on the tensometer with its attachment fixed
properly bending strengths were evaluated.
Copyright © 2012 SciRes. JMMCE
Copyright © 2012 SciRes. JMMCE
2.4.3. Izod Impact Test ous that sisal laminate displayed the highest (42.0 MPa)
compressive strength, followed by ukam laminate, then
E-glass laminate, while the banana showed the lowest
(16.75 MPa) compressive strength. Figure 2 shows the
measured tensile strength of treated natural fibres. The
tensile strength decreases from E-glass laminate with
highest (63 MPa) tensile strength, ukam laminate (16.25
MPa), while hemp laminate showed the least (7.0 MPa)
tensile strength. However other parameters that are im-
portant are assessed for good suitability.
The impact strength of notched specimen was determined
by using an impact tester according to ASTM D 256-05
standards. In each case three specimens were tested to
obtain average value.
3. Results and Discussion
The test results are shown and discussed in this section.
Average values of three replications of the tensile test,
the bending test, the compressive test, and the impact test
are tabulated in Table 1. 3.2. Bending Strength
Figure 3 shows the bending strength of alkalized natural
fibres. E-glass displayed highest (0.50 MPa), next to it is
sisal laminate, followed by coconut and hemp, while
ukam and banana showed the least (0.0013 MPa) bend-
ing strength.
3.1. Compressive and Tensile Strength
Figures 1 and 2 show the compressive and tensile strength
of the alkalized treatment of ukam, banana, sisal, coconut,
hemp and E-glass fibres. From the histograms, it is obvi-
Table 1. Mechanical properties of various composite laminate.
properties Ukam fibre
Laminate Banana fibre
laminate Sisal fibre
Laminate Coconut fibre
laminate E-glass
laminate Hemp fibre
Compressive strength (MPa) 39.25 16.75 42.00 30.35 37.75 29.75
Tensile strength (MPa) 16.25 6.50 5.40 3.20 63.00 7.00
Bending strength (MPa) 0.0013 0.0013 0.0036 0.0021 0.500 0.0017
Impact strength ( J /m2) 9.89 7.47 8.36 8.36 17.82 7.41
Figure 1. Compressive strength of alkalized treatment of natural fibre reinforced laminate samples.
Figure 2. Tensile strength of alkanized treatment of natural fibre reinforced laminate samples.
Figure 3. Bending strength of alkanized treatment of natural fibre reinforced laminate samples.
Figure 4. Impact strength of alkanized treatment of natural fibre reinforced laminate samples.
3.3. Impact Strength
Figure 4 shows the izod impact strength results of rein-
forced fibre laminates. The ukam laminate tested dis-
played higher impact strength (9.87 J/m2) next to E-glass
laminate (17.82 J/m2), while the hemp and bananana dis-
played the lowest (7.477 J/m2).
The alkalization treatment of fibers helps in improving
the chemical bonding between the resin and fiber result-
ing in superior mechanical properties. It has been re-
ported by several authors that mechanical properties of
composites were improved by the modification of fibers
4. Conclusions
The experimental investigation on mechanical properties
of natural fiber reinforced composites leads to the fol-
lowing conclusions:
1) The natural fiber composite manufactured by hand
lay-up process provides an opportunity of replacing ex-
isting materials with a higher strength, low cost alterna-
tive that is environmentally friendly.
2) Mechanical properties viz., Compressive strength,
Bending strength, Tensile strength, and Impact strength
of the ukam and sisal fiber reinforced composite material
is greatly influenced by alkalization treatment. Hence,
ukam and sisal fibers can be good reinforcement candi-
dates for high performance polymer composites.
3) Ukam and sisal composites manufactured by hand
lay-up process provide an opportunity of replacing exist-
ing materials with a higher strength, low cost alternative
that is environmentally friendly.
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