/div>
= density, m = mass, v = volume of sample.
final weightinitial weight
%Weight gained100
initial weight
(2)
3. Result and Discussion
3.1. Physical Properties of Coconut Shell Powder
Reinforced Polymer Matrix Composite
From Figure 1, it can be seen that the sample with the
highest volume of coconut shell particles (25%) has the
most consistent rate of absorption in water. When com-
pared with the control sample containing 0% coconut
shell particles has a lower rate of absorption in water
after 120 hou rs.
From Figure 2, as the filler increases, the porosity of
the composites decreases. The water absorption is due to
the hydrophilic nature of the coconut shell.
Table 1. Chemical composition of coconut shell powder in
(mg/L).
Metal Ca Fe Si Al Mn
Composition28.8841.882 - - -
Figure 1. Effect of coconut shell particles addition on the
rate of absorption of particulate coconut shell reinforced
polyethylene.
Figure 2. Effect of coconut shell particles addition on the
density of particulate coconut shell reinforced polyethylene
composite.
Copyright © 2012 SciRes. JMMCE
J. O. AGUNSOYE ET AL.
776
3.2. Mechanical Properties of Coconut Shell
Powder Reinforced Polymer Matrix
Composite
The coconut shell particles have significant effect on the
strength, hardness, and impact energy of the composite.
From Figure 3, it can be seen that the tensile strength of
the composites decrease with increase in the volume
percent of the coconut sh ell particles within the matrix of
the composite. The polyethylene composite with the
highest volume fraction of filler (25%) has the lowest
strength (6.59 MPa). This may be due to imperfect inter-
facial bonding between the coconut shell coconut shell
particles and polyethylen e matrix.
As expected, the yield strength values of the composite
samples decrease with increase in the volume of the co-
conut shell particles (See Figure 4).
From Figure 5, the ductility of the composites de-
creases with an increase in volume fraction of the coco-
nut shell particles within the sa mples. Samples with 20%
and 25% volume fraction of coconut shell particles have
the same strain valu e (0.9021), extrapolated fro m Figure
5.
Figure 3. Effect of coconut shell particles addition on the
tensile strength of coconut shell reinforced polyethylene
composite.
Figure 4. Effect of coconut shell particles addition on the yield
strength of coconut shell reinforced polyethylene composite.
From Figure 6, it can be seen that there was a sharp
decrease in the rigidity of the sample with 5% coconut
shell particles within the matrix of the composite. But, as
the volume fraction of the coconut shell particles in-
creases from 5% to 25%, the modulus of elasticity of the
samples increases with 69.5 MPa obtained for the com-
posite which has 25% volume fraction of coconut shell
particles. This value (69.5 MPa) is high er than that of the
sample without any reinforcement (i.e. 0% filler).
From Figure 7, it can be seen that the hardness of the
composite increases with increase in the coconut shell
Figure 5. Effect of coconut shell particles addition on the
strain of coconut shell reinforced polyethylene composite.
Figure 6. Effect of coconut shell particles addition on the
modulus of coconut shell reinforced polyethylene composite.
Figure 7. Effect of coconut shell particles addition on the
hardness of coconut shell reinforced p olyethylen e compos ite.
Copyright © 2012 SciRes. JMMCE
J. O. AGUNSOYE ET AL.
Copyright © 2012 SciRes. JMMCE
777
de
olyethylene matrix
of the composite. The appearance of the gold as seen in
the EDS results is indicative of the composition of the Al
foil used as a laminatio n material to prevent the compo s-
ite from sticking to the die mould surface during and
after compaction and hot pressing using a two-roll rheo-
mixer.
particles content within the matrix of the compos ite. The
sample having the highest coconut shell coconut shell
particles shows the highest har dness value of 11.4 HRB.
From Figure 8, the impact energy of the composite
creases with an increase in coconut shell particles con-
tent within the matrix of the polyethylene coconut shell
reinforced composite. The sample with 25% volume
fraction coconut shell particles in the matrix h as the low-
est impact energy of 1.76 J.
3.3. Microstructural Analysis
The control sample represents the p
sample without coconut shell particles (particulate coco-
nut shell) additions (See Plate 1). From Plates 2-6, it can
be seen from the Scanning Electron Microscope results
that homogeneity between the coconut sh ell particles and
the matrix decreases with increase in the coconut shell
particles content. This explains the decrease in strength
with increased in the coconut shell particles content
within the matrix structure of the composite. The in-
crease in hardness is as a result of the increase in the
volume percent o f the coconut shell particles within matrix Figure 8. Effect of coconut shell particles addition on the
impact of coconut shell reinforced polyethylene composite.
Plate 1. SEM & EDS microanalysis of polyethyle composite without coconut shell particles additions.
ne matrix
Plate 2. SEM & EDS microanalysis of polyethylenmposite with 5% coconut shell particles addition. e matrix co
J. O. AGUNSOYE ET AL.
778
Plate 3. SEM & EDS microanalysis of polyethylene mposite with 10% coconut shell particles addition.
matrix co
Plate 4. SEM & EDS microanalysis of polyethylene mmposite with 15% coconut shell particles addition. atrix co
Plate 5. SEM & EDS microanalysis of polyethylene mmposite with 20% coconut shell particles addition. atrix co
Copyright © 2012 SciRes. JMMCE
J. O. AGUNSOYE ET AL.
Copyright © 2012 SciRes. JMMCE
779
Plate 6. SEM & EDS microanalysis of polyethylene mposite with 25% coconut shell particles addition.
. Conclusions
the investigations and discussio
oconut shell parti-
cl
percentage of coconut shell particles in
cr
rove the hardness
er
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From the results of n, the
following con clusions as been drawn:
1) The non-uniform distribution of c
e in the microstructure of the coconut shell reinforced
polyethylene composite is the major factor responsible
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Plates 1-6).
2) As the-
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