International Journal of Engineering & Technology IJET-IJENS Vol:10 No:04
8
Study of the Optimum Condition Towards the
Inducing Paraffin Wax LDPE
(1)
(2)
Kannan Rassiah (1), Mohd Yuhazri Yaakob (2), Haeryip Sihombing (2), and Puvanasvaran Perumal(2)
Department of Mechanical Engineering. Politeknik Merlimau. KB 1031, Pejabat Pos Merlimau-Melaka MALAYSIA
Faculty of Manufacturing Engineering. Universiti Teknikal Malaysia Melaka, Durian Tunggal-Melaka MALAYSIA
Email: [email protected]
Abstract— Low Density Polyethelene is a thermoplastic
resin extracted from petroleum based, whereas the wax is an
oily organic component that is contains of alkanes, ester,
polyester, and hydroxyester. The purpose of this research is to
find out the optimum conditions of the wax produced by
inducing LDPE. The experiment is carried out by mixing the
wax and LDPE into four new polymer compositions, in which
the higher value of the tensile strength, Young’s modulus,
and hardness are obtained by mixing between 90 wt. % LDPE
with 10 wt. % wax, rather than compared to pure LDPE. The
results are 8.896 MPa, 247.602 MPa and 50.9 respectively.
However, only the strength impact that has a lower value as
much as 31.38 %. By S EM analysis, the improvement of
mechanical properties value examined in which the most
suitable of optimal composition is 90 wt. % LDPE with 10 wt.
% wax. The LDPE/wax mixture produces a new polymer and
alters the properties of pure LDPE.
Index Term-- low density polyethylene, paraffin wax, new
polymer.
I.
INT RODUCT ION
Polymer is a long chain of repeated atoms and produced by
joining the molecules which are known as monomers . The
Low Density Polyethelene (LDPE) is a first grade of the
Polyethylene group which was produced in 1933 by Imperial
Chemical Industries by using high pressure and ‗free radical
polymerisation‘ techniques [3], while the wax is an organic
compound which is categorized into two types, that is
natural wax and modified wax. Both types of wax create
higher potential as the reinforcement agent in polymers. The
reason to choose the natural wax in this research due to the
cost of manufacturing as well as it widely used for consumer
products.
II.
M AT ERIAL AND M ET HODS
This research use low-density polyethylene as the matrix
material in the form of pallet and the wax as reinforcement
material. The wax material was obtained from the candle
sticks that have been processed by the manufacturers. Most
of the candles are made of parafin, but it can also made from
bees wax, soya, plants as well as cow‘s fat (a side product of
the beef fat), wheras the gel wax is made from paraffin and
plastic.
Chemically, a candle contains of various compounds
such as alkanes, esters (contains acid and alcohol),
polyesters, low hydroxyester alcohol, and fatty acids. The
wax differs from fat because it lacks triglyceride ester
glycerine propan 1,2,3 triol and three fatty acids. High
melting point and hardness of karnauba candle occurs
when ester is added [1].
The formulation for LDPE and wax is divided into five
main compositions ratio as shown in Table 1. Every material
is mixing into a beaker placed on the top of hot plate
magnetic stirrer. The set up parameter for the surrounding
temperature is fixed with range 95 ºC to 125 ºC with fixed
rotator is 600 rpm. The blending takes about 45 minutes to
produce uniform mixture.
T ABLE I
COMP OSITIONS RATIO OF LDPE/WAX
Compositions
A
B
C
D
E
wt. % LDPE
100
90
80
70
60
wt. % Wax
0
10
20
30
40
By using crusher machine, the compounds are processed
into smaller sizes. This process is to ensure that both of the
materials are uniformly mix and no lumps presence due to the
smaller lumps are able to influence the accuration of data
analysis. The LDPE/wax compound was compress ed for 15
minutes under 20 tonnes at temperature of 175 ºC followed
by cooling at room temperature. Five types of new polymer
composition are cut and tested for tensile, harness, and
charpy characteristics according to ASTM D-638 08, ASTM
D-785 08 and ASTM D-6110 08 respectively. The
microscopic observation is carried out to observe the
cracked surface after all of the LDPE/wax polymer subjected
into three mechanical testing. Here, the morphology of the
cracked surface is observed by using scanning electron
microscopy (SEM) at three types of magnifications that are
250X, 500X and 1000X, which consists of topographical,
morphological and composition pictures.
III.
RESULT S AND DISCUSSION
Tensile test
The test for tensile strength test is being done against the
four major compositions of the mixture with the percentage
of LDPE and wax in between 90 % to 40 %. This refers to the
objective priority of the research that is to find the higher
value of tensile strength for the LDPE/wax composition of
103404-0707 IJET-IJENS © August 2010 IJENS
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International Journal of Engineering & Technology IJET-IJENS Vol:10 No:04
Stress (MPa)
10
Chart of tensile strength against percentage
composition of LDPE
8.896
8.3
7.222
8
6
4.166
4
2.518
2
0
60
70
80
90
100
LDPE wt%
Graph of Durometer strength reading against percentage of
composition of LDPE
Streangth Reading (shore)
the manufacturing process . The LDPE 90 wt. % and wax 10
wt. % mixture was observed and the tensile strength is
higher compared to the other wt. % compositions. The
addition of wax shows a pattern of decrease in its tensile
strength and modulus tensile compared to pure LDPE. At an
earlier stage, the addition of 40 wt. % wax caused a
decreasing pattern of the tensile strength data, compared to
pure LDPE. However, while the wax is further decreased from
40 wt. % to 10 wt. %, then the tensile strength will increase
[5] – [8]. The result is as shown in Figure 1 and Figure 2.
9
60
50
46.44
50.9
47.8
45.06
40
37.64
30
20
10
0
60
70
80
90
100
LDPEwt%
Fig. 3. Graph of Durometer strength reading against percentage of
composition of LDPE
Charpy impact test
Figure 4 proven that the LDPE/wax is lower than pure
LDPE. Theoretically, pure LDPE has high ductile strength
and elasticity. From 90 wt. % LDPE mixture, the value of
energy absorbed is close to pure LDPE, but for 60 wt. %
LDPE mixtures, the value has decreased, while in 80 wt. %
LDPE mixture, the value increases but it is lower compared to
pure LDPE [2].
Fig. 1. Chart of tensile strength against percentage composition of
LDPE
Graph of impact strength against LDPE percentage of
composition
Modulus of elasticity (MPa)
300
247.602
250
205.672
200
222.5
impact strength(J/mm2)
0.03
Chart of tension modulus against percentage
composition of LDPE
0.0274
0.025
0.02
0.0188
0.015
0.0144
0.01
0.00922
0.005
0.00412
0
170.028
170
60
70
80
90
100
LDPE wt%
150
100
Fig. 4. Graph of impact strength against LDPE percentage of
composition
50
0
60
70
80
90
100
LDPE wt%
Fig. 2. Chart of tension modulus against percentage composition of
LDPE
Hardness test
The high hardness value of the mixture shows the
property of the material, which has high hardness level. The
hardness value of 60 wt. % LDPE is 37.64 meanwhile the
value for 90 wt. % LDPE is 50.9. The significant differences in
the value shows that the high percentage of wax will
decrease the hardness of the material as the bonding
between the molecules become irregular. Comparison is also
done between pure LDPE and 90 wt. % LDPE and it shows
that the hardness value of pure LDPE is lower than 90 wt. %
LDPE, that is, 46.44. The ductile property of pure LDPE is
unable to withstand hardness. The hardness value of pure
LDPE and LDPE/wax is calculated and shown clearly in
Figure 3.
Surface morphology of cracked specimens
The analyses towards surface morphology of the broken
specimens carried out by using scanning electron
microscope after the impact testing. The morphology is used
to identify the bonds between the LDPE and wax structures.
It is also used to find the changes on the material after being
tested with a strong impact.
wax
LDPE
Fig. 5. Mixture of 60 wt. % LDPE (1000X)
The X- ray test is also done to identify the contents of the
mixture. The energy traces represents the overall energy of
103404-0707 IJET-IJENS © August 2010 IJENS
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International Journal of Engineering & Technology IJET-IJENS Vol:10 No:04
the impact on the specimen whereas the strength of the
impact represents the overall energy that has been absorbed
by the specimen when weight is applied.
Figure 5 shows the wax 40 wt. % has covered the borders
and most of the area. This caused the bonds between LDPE
to be broken and changed the mechanical properties . It also
decreased the tensile strength [4], [6], [8]. From the result
also shows the percentage of carbon is 67.06 wt. %. This
proves the presence of carbon in the mixture because LDPE
and wax contains high percentage of carbon.
10
shows that the LDPE molecule has started to bind with the
wax molecules, consequently adding the carbon wt%.
wax
LDPE
Fig. 8. Mixture of 90 wt. % LDPE (1000X)
wax
LDPE
Fig. 6. Mixture of 70 wt. % LDPE (1000X)
Figure 6 shows 70 wt. % LDPE that is very different of 60
wt. %, because the LDPE structure can be seen. Even though
the certain areas of the molecule are covered with wax. The
tensile strength also decreased, but it remains higher than 60
wt. % LDPE [4], [7], [8]. The percentage of carbon in this
mixture increases up to 69.82 wt. %. The increase of LDPE
influences the percentage of carbon.
LDPE
wax
Fig. 7. Mixture of 80 wt. % LDPE (1000X)
In this mixture as shown in Figure 7, the changes can be
seen in the properties. The wax is the binder for LDPE. The
wax molecules have covered the borders and have started to
bind the LDPE molecules, indirectly modifying the
mechanical characteristics of the LDPE [4], [6], [8]. The high
percentage of LDPE has increased the carbon wt. % in the
mixture up to 77.16 wt. % and the morphological picturisation
In Figure 8, it can be seen that the mixing ratio has started
to properly occur and produce a new LDPE/wax properties
where the polymer has combined regularly. The wax is found
in all the borders and tied the molecules of the polymer. The
tensile strength increases , although the pure LDPE
properties is still maintain [4], [6], [8]. By increasing of the
carbon‘s percentage up to 81.80 wt. % in this composition,
it‘s proves that the addition of LPDE in this mixture will
strengthen the percentage of carbon in this molecule and the
wax will act as the binder for this molecule.
IV.
CONCLUSIONS
Based on the mechanical properties results (which is
obtained from the tensile strength test and hardness test), it
is known that the mechanical characteristics of LDPE
increases. However, its decreases when the impact test is
done. This shows that the mixture is hard, but it is more
ductile compared to pure LDPE.
Based on the observation, the best wt. % mixture for these
two materials is 90 wt. % LDPE and 10 wt. % wax. This wt. %
has increased the mechanical characteristics of the pure
LDPE. The morphology test on the broken surface shows
that the adhesion between wax and LDPE is a strong bond.
But if the mixture is unproportional, then the LDPE
characteristics will decrease.
The research also shows that is apart of increasing the
strength against an object, LDPE also able to increase the
income due to wax is less expensive and readily available.
The usage of injection moulding process will als o improve
because the wax acts as a conductor during this process.
A CKNOWLEDGMENT
The authors would like to thanks Director of Polytechnic
Merlimau Melaka, Head of Mechanical Engineering
Department, as well as The Unit of Research, Innovation &
Entrepreneurship of Politeknik Merlimau whose supports the
project.
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International Journal of Engineering & Technology IJET-IJENS Vol:10 No:04
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