![Wasit Journal for Science & Medicine 2016: 9(3): (99-108)
011
Introduction
For the purpose of obtaining materials
with desirable mechanical and thermal
properties, a new material called
composites materials are manufactured
contained the matrix material and
reinforcement material , generally
composite can be defined as a materials
system which is comprised of two or
more physically distinct phases whose
combination produces aggregate
properties that are different from those
of its constituents and it may provide
superior and unique characteristics its
combines the most desirable
characteristics of its constituents while
suppressing their least desirable
characteristics. The matrix material
(continuous phase) as is the case with
polymers deal with different types of
Fillers (dispersed phase) which are fiber
or particulates in the form of micro scale
regularly distributed in the matrix
material polymer [1,3].
In the last years, the polymer has been
playing an important role in composites
materials. Because of the paucity of
metals and many scientists are looking for
new and the alternative metals.
Composites materials are attractive
because of their low cost, easy produce,
good mechanical properties, and so forth.
Among those alternatives unsaturated
polyester is the characterization of high
performance and operating at a fast rate
(attractive) due to its dimensional
stability, low price, and light weight [4). It
belongs to the thermosetting group of
polymers (hard and stiff cross linked
material that does not soften or become
moldable when heated). They offer
exciting advantages from the viewpoint of
there was widely applications [5].
A composite material whose reinforced by
a particle and all the dimensions of
particle approximately equal (equiaxed) is
called particulate reinforced composites.
polymers using fillers as a reinforcement
whether inorganic or organic, is common
in the field of production of modern
polymeric dielectrics for improved
discharge resistance, matching of the
coefficient of thermal expansion, and
higher thermal conductivity as well as
mechanical reinforcement, abrasion and
wear resistance and long-term mechanical
behavior[6]. Polymer composites are
manufactured commercially in many
different applications such as sporting
goods, aerospace components,
automobiles, etc. and they are generally
used for buildings, such as shower stalls,
bathtubs, and imitation granite and
cultured marble sinks [7].
The final properties of composites
materials affected by several factors
related to properties of matrix material
and the reinforcement material properties
such as the type, size and shape of the
Particulate fillers and distribution within
the matrix material and must be uniformly
distributed [8], particle–matrix interfaces
adhesion and particle loading. Particle
size has an evident effect on these
mechanical properties [9].There is several
researchers doing for improving
mechanical and physical properties for
composite materials.
A. A. Kareem (2013) studied the
mechanical properties (tensile and
flexural) of granite powder filled](https://image.slidesharecdn.com/12-250110131946-54455e15/85/Studying-Some-Mechanical-and-Physical-Properties-of-Polyester-Granite-Microcomposites-3-320.jpg)
![Wasit Journal for Science & Medicine 2016: 9(3): (99-108)
010
polycarbonate (PC) toughened epoxy
composites and the effect of the chemical
resistance on these properties. The results
showed good chemical resistance for the
prepared composites and better
mechanical properties was observed for
composites reinforced with 20% granite
[10]. S. M. Hassan et.al (2014) prepared
(Epoxy – Granite) composite with
different percent volume of Granite
powder and investigated the effect of acid
immersion on the hardness of composites.
Hardness test was conducted for all
samples in two conditions (normal
condition and after immersion in HCL
solutions for periods ranging up to 10
weeks .It was observed that the hardness
increased with increasing the weight
percent of granite, and Hardness values
for the composites before immersion in
HCL (1 M and 2 M) solutions are greater
than values of composites after immersion
[11].
Materials and Methods
1- Materials Used
The materials used to prepare the composite
samples are:
1- Unsaturated Polyester Resin (UPE)
made by (SIR) company from Saudi
Industrial Resin Limited with low
viscosity, high reactivity and density
from1 to1.3 g/Cm3
at 25°C.
2- Methyl ethyl ketone peroxide (MEKP)
made in Jordan, the chemical formula
(C8H16O4) and with specific gravity 1.17
is across linking (hardener) for an
unsaturated polyester resin.
3- Granite particles made in Turkey with
particle size (53µm).
2- Sample Preparation
1-To prepare pure specimens unsaturated
polyester resin and thermally hardened
which is Methyl Ethyl Keton peroxide
(MEKP) was mixed by using the
mechanical mixer, the weight ratio
between hardener and resin was 2 gm of
hardener per 100 gm of the resin at room
temperature to form a strong permanent
band converted to a solid state specimen
by putting it in suitable template and after
that all the specimens Left at room
temperature about 24 hours to cure then
placed after hardening in an electric oven
in temperature of 60˚C for a period of 2
hours. This process is called fast treatment
(post-curing) and after the completion of
this process, the specimen becomes ready
for a final examination.
2-The technique used to prepare the
UPE/granite composites specimens was
Hand lay-up, it is a simple way to use and
can from which to obtain specimens of
different shapes and sizes. UPE resin was
mixed with granite; the contents were
mixed thoroughly until homogeneous
mixture was obtained, by using the
mechanical mixer and then hardener
(MEKP) was added to the mixture.
Finally, they were cast in moulds, the
specimen shape prepared for mechanical
and physical test are identical to the
specification of ASTM for each test. After
that all the specimens Left in the room
temperature about 24 hours to the cure
and then for post-curing, the specimens
were left for 2 hours in an electric oven at
temperature 60˚C.Figure (1) shows all
prepared specimens.](https://image.slidesharecdn.com/12-250110131946-54455e15/85/Studying-Some-Mechanical-and-Physical-Properties-of-Polyester-Granite-Microcomposites-4-320.jpg)
![Wasit Journal for Science & Medicine 2016: 9(3): (99-108)
011
Figure (1): Shows the prepared
specimens for testing.
3-Experimental Tests
Tests such as, diametrical compression
strength, hardness, thermal conductivity
and dielectric strength, were carried out
on micro composites. We have used in
this research a set of devices for the
purpose of testing the samples. For
hardness (Shore D) has been taking at
least three readings in different places of
the specimen, while the other tests, it was
examined at least three prepared
specimens and the mean values were
reported. In order to investigated the
effect of granite microparticles on the
mechanical and physical properties of the
composites.
3-1 Diametrical Compression
The use of diametrical compression test as
a mechanical technology testing technique
spanning many technological fields and
used in estimating strength of the
materials elastically deform, which are
susceptible to brittle fracture. It was also
known as the diametrical tensile test,
Brazilian disc test, indirect tensile test,
compact crushing test, or compact
hardness test [12]. It allows for
diametrical compressive test for the use of
simple specimen geometry (disc, compact,
tablet, etc.) to measure a limit force
required to cause failure, which is used in
the estimation of tensile strength which is
given by the equation[1]. In the
diametrical compression test, we assume
that the tensile strength of the specimen
can be expressed in terms of the
maximum principal tensile stress in the
specimen. Figure (2) shows the geometric
shape of specimen and the method of load
shedding.
The diametrical compressive test was
conducted for all specimens to determine
the diametrical compressive strength by
using equation (1) (12, 13), and the
instrument from Gunt Hamburg company.
Where is the diametrical
compression strength (N/mm2)
.
is the maximum load (force at
fracture) indicated by the testing machine
(N)
is the diameter of the specimen
(40mm), and is the thickness of
specimen(mm).
Figure (2): Shows the geometric shape
and the method of shedding the load on
the specimen (16).](https://image.slidesharecdn.com/12-250110131946-54455e15/85/Studying-Some-Mechanical-and-Physical-Properties-of-Polyester-Granite-Microcomposites-5-320.jpg)
![Wasit Journal for Science & Medicine 2016: 9(3): (99-108)
012
3-2 Hardness
Hardness is another mechanical property
that can be important to be considered, it
is a measure of the resistance of the
material to permanent deformation (bent,
broken or shape change) or damage
[14].Shore D Durometer Hardness was
specific to measure the hardness of
polymeric materials which thermally
solidified (Thermosetting Polymer). It
provides a very good idea about of
material properties of the durability and
cohesion of material mass and also by
using small loads [15].
Hardness test was conducted for
UPE/granite composites at different
weight percentages (0, 5,10,15,20 and30)
% to investigate the effect of granite
particle on the hardness of prepared
specimens by using Shore D Durometer
Hardness tester fabricated by TIME
GROUP INC Company was used to
measure the hardness test by using the
pointed dabbing tool. The pointed dabbing
tool penetrates the material surface by the
pressure applied on the instrument where
the dabbing tool head touching quite the
surface of the specimen then calculate the
values hardness for the specimens through
the penetration of the Durometer indenter
foot into the specimen.
3-3 Thermal Conductivity
Thermal conduction is the
phenomenon by which heat is transported
from high to low-temperature regions of a
substance. So the property that
characterizes the ability of a material to
transfer heat is the thermal conductivity,
the heat is transported by lattice vibration
waves (phonons) and free electrons in
solid materials. A thermal conductivity is
associated with each of these mechanisms
and the sum of the both two contributions
gives the total conductivity (K=Kl+Ke).
Thermal conductivity was carried out for
all prepared specimens with the diameter
(40 mm) by using (Lee's Disc) and
applying equation [2](8,16).
[ ] [ ( )
]
The value of (e) calculated from the
equation [3] through knowing that the
energy entering the heater equal energy
outgoing [17).
[
] 3)
Where K is thermal conductivity (W/m
e is heat loss in (sec) in unit area (m2
)
and different in the temperature between
discs and environment, d1, d2, d3 are
thickness of the discs in(m), is the
thickness of specimen in(m) , r is radius
of the disc in (m),T1,T2,T3 is temperature
at disc1,2,3 respectively in ( )and I is
current throw the heater coil in Ampere
and V is the voltage on the heater in Volt.
3-4- Dielectric Strength
There are many properties of dielectrics
are important such as dielectric constant,
dielectric loss and dielectric strength
(Breakdown Voltage), one of them is
dielectric strength which represented the
average potential per unit thickness at
which failure of the dielectric material
occurs the electric field magnitude that
required for causing dielectric breakdown](https://image.slidesharecdn.com/12-250110131946-54455e15/85/Studying-Some-Mechanical-and-Physical-Properties-of-Polyester-Granite-Microcomposites-6-320.jpg)
,by using the dielectric strength
instrument type (BAUR PGO S 3)
Germany origin.
Eb:r :is the dielectric strength and
calculated in units: (Kv/sec.mm)
Ubr: is the break down voltage in (Kv/sec)
which represents the reading device and
The values of diametrical compression
strength, hardness, thermal conductivity
and dielectric strength (breakdown
voltage) together with their significances
are summarized in Table (1).
t: is the thickness of insulator.
Table1: The values of some mechanical and physical properties for UPE and UPE/granite
composites.
Results and Discussion
The plotted curve Figure (3) illustrated the
diametrical compression strength of
granite particles reinforced polyester
composites as a function of the weight
percentage (0, 5, 10, 15, 20, and 30) % of
granite. As the data in Table (1) has
appeared, the diametrical compression
strength was increased from 3.24 to 7.02
N/mm2
for UPE and with addition of 30%
granite particles, granite improved the
diametrical compression strength
by116.66% at 30% granite, this due to
high degree of adhesion between the
polymer molecules and granite particles,
because the granite act as binding
materials (19). as well as for this enhanced
in the behavior of compression strength is
due to the supposition role for
reinforcement particles in obstruction the
growth and progress of cracks and an
increase in resistance of material to
deformation.
Figure (4) represented the variation of the
shore hardness values with the weight
percentage of granite particles; it shows
that the hardness increased with increasing
granite particles. It was increasingly
nonlinear relations with the increase in the
weighted percentage of granite particles
but the rate of increase varies from one
percentage weight to another.
Specimen
identifier
diametrical
compression
strength(N/mm2
)
Hardness Thermal
Conductivity
(W/m.
Dielectric strength
(Kv/sec.mm)
UPE 3.24 81.4 0.376 6.41
UPE/5%G 4.68 83.2 0.403 8.22
UPE/10%G 5.32 84.1 0.435 8.45
UPE/15%G 6.46 85.5 0.451 8.97
UPE/20%G 7.02 86.7 0.471 8.64
UPE/30%G 8.49 87.9 0.500 9.41](https://image.slidesharecdn.com/12-250110131946-54455e15/85/Studying-Some-Mechanical-and-Physical-Properties-of-Polyester-Granite-Microcomposites-7-320.jpg)
![Wasit Journal for Science & Medicine 2016: 9(3): (99-108)
014
As the polymers have low hardness so the
lowest value obtained for pure unsaturated
polyester before reinforcement it was
(81.4), while was (87.9) at the percent of
granite particles (30 wt %). This is may be
attributed to increasing the surface area of
granite particles in contact with
unsaturated polyester and decreasing the
movement of polymer molecular which
lead to the rise of the strength of the
material to scratch and increasing of the
material strength to plastic deformation
[17]. The result is in good agreement with
results obtained for unsaturated polyester
resin reinforce with Fe weave wire (20),
also agree with results obtained by
Ahmed[05) which showed that a very
high hardness for composites(AL-B4C)when
increased percentage of boron carbide
particles as compared to the hardness of
aluminum matrix alone which was
indicated a good interconnection between
Aluminum matrix and boron carbide in
addition carbide particles seems to work as
barriers to the deformation of matrix
material the foundation and inhibit the
growth and progress of cracks when they
occur, causing a significant increase in
resistant material for high flow and an
increase in the hardness.
Figure (5) shows that thermal conductivity
values increase when polyester resins fill
by granite particles, From the results
obtained thermal conductivity was
increased from (0.376 W/m. ) for UPE to
(0.403 W/m. ) at 5 wt. % granite
particles and then increase from (0.435
W/m. ) at10wt% to (0.451 W/m. ) at 15
wt. % until reaches maximum value
(0.5W/m. ) at 30 wt. % granite particles
as shown in table (1),also the amount of
the difference between the temperatures
(T1 & T2) for the composite sample
surfaces less as the weighted percentage
increased. This is due to the surface area
of the particles will be the larger and the
interstitial spacing between the particles
be less when percentage weight of the
reinforcement increase and therefore have
influence clear on thermal conductivity. In
addition, the reinforcement material has a
crystalline structure in which the atoms are
arranged in accordance with the three-
dimensional crystalline network (8).
0
1
2
3
4
5
6
7
8
9
0% 5% 10% 15% 20% 25% 30% 35%
Diametrical
Compression
Strength(N/mm2)
Wt.% of Granite Particles 81
82
83
84
85
86
87
88
89
0% 5% 10% 15% 20% 25% 30% 35%
Shore.D(Hardness
No.)
wt.% of Granite Particles
Figure (3): Diametrical compression strength
vs. the weight percentage of granite particles
for UPE/granite composites
Figure (4) Hardness vs. the weight
percentage of granite particles for
UPE/granite composites](https://image.slidesharecdn.com/12-250110131946-54455e15/85/Studying-Some-Mechanical-and-Physical-Properties-of-Polyester-Granite-Microcomposites-8-320.jpg)
Studying Some Mechanical and Physical Properties of Polyester/Granite Microcomposites
- 1. See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/328703861 Studying Some Mechanical and Physical Properties of Polyester/Granite Microcomposites Article · November 2016 CITATIONS 0 READS 233 1 author: Najwa J. Jubier Wasit University 46 PUBLICATIONS 247 CITATIONS SEE PROFILE All content following this page was uploaded by Najwa J. Jubier on 02 November 2018. The user has requested enhancement of the downloaded file.
- 2. Wasit Journal for Science & Medicine 2016: 9(3): (99-108) 88 Studying Some Mechanical and Physical Properties of Polyester/Granite Microcomposites Najwa Jassim Jubier University of Wasit , College of Science, Department of Physics. بعض دراسة البولي لمتراكبات والفيزيائية الميكانيكية الخصائص اس كرانيث/تر المايكروية انفُشَاء قسى ،انعهىو كهُت ، واسظ جبُزجايعت جاسى َجىي ا لمستخلص هذا ٍي انهذف انعًم انًُكاَُكُت اانخصائص بعض دراست هى و انفُشَائُت يخزاكبت نًىاد راحُجاث ًعه ٌححخى غ انبىنُسخز ُز ان ودقائق اساص كًادة انًشبعت ك انًاَكزوَت زاَُج ( 35 بخىظُف عهُها حصهُا ٍانخ )ياَكزويخز و .يذعًت كًادة اسخخذيج ٍوانخ انًُاسب انحجى ًعه نهحصىل انًُاخم ٍي يجًىعت قذ حضزث عُُاث انًخزاكب إضافت حى وقذ.ٍيُكاَُك خالط باسخخذاو انُذوَت انقىنبت حقُُت بىاسطت دقائق َانكزا وسَُت بخزاكُش ُج ( يخخهفت 0 ، 3 ، 00 ، 03 ، 00 و 50 ان دقاائق إضافت ٌأ انخجزَبُت انُخائج وأظهزث.% ) ك زاَُج يقاويت قُى ٍححس ٍي انصالة قًُت حشداد حُث انصالدة قُى ٍف سَادة أَضا وحسبب انقطزَت االَضغاط 40.8 انبىنُسخز نزاحُجاث ًإن انًشبعت غُز 4..8 حزكُش عُذ 50 ان ٍي% كز وكذنك ،اَُج ٍححس حُث ،انعشل ويخاَت انحزارَت اانًىصهُت ح ى حقذَزها ن دانت أَها ًعه ُسبت ان ك زاَُج انًضافت ، انعشل وويخاَت انحزارَت انًىصهُت قُى ٌأ ٍُوحب يع حشداد سَادة َسبت ان ك ،زاَُج و ٌا ف حقم انعشل يخاَت قظ عُذ انىسَُت انُسبت 20 ٪ . ،عًىيا ٍف جُذ ٍححس نىحع َخائج حهك انخصائص . AbstractThe aim of this work is studying some mechanical and physical properties of composite materials containing unsaturated polyester resin as a matrix and granite microparticles (53µm),which obtained by employing the set of sieves to get the suitable size used as a reinforced material. The specimens of the composite were were particles Granite . er mechanical mix the with up technique - by hand lay prepared added at different concentrations (0, 5, 10, 15, 20 and 30) wt. %. The experimental results showed that addition of granite particles enhancing values of diametrical compression strength also caused an increase in hardness No. values it increases from as , concentration granite of 30 wt. % at 87.9 to resin for unsaturated polyester 81.4 well as thermal conductivity and dielectric strength, it has been evaluated as a function of the additive percentage of granite and it was found that the values of thermal conductivity and dielectric strength increase with increasing granite content, it was obtained that the dielectric strength decreased only in weight percentage20%. Generally, it was observed good improvement in those characteristics results. Key Words: unsaturated polyester resin, granite particles, shore hardness, diametrical compression strength, thermal conductivity, dielectric strength.
- 3. Wasit Journal for Science & Medicine 2016: 9(3): (99-108) 011 Introduction For the purpose of obtaining materials with desirable mechanical and thermal properties, a new material called composites materials are manufactured contained the matrix material and reinforcement material , generally composite can be defined as a materials system which is comprised of two or more physically distinct phases whose combination produces aggregate properties that are different from those of its constituents and it may provide superior and unique characteristics its combines the most desirable characteristics of its constituents while suppressing their least desirable characteristics. The matrix material (continuous phase) as is the case with polymers deal with different types of Fillers (dispersed phase) which are fiber or particulates in the form of micro scale regularly distributed in the matrix material polymer [1,3]. In the last years, the polymer has been playing an important role in composites materials. Because of the paucity of metals and many scientists are looking for new and the alternative metals. Composites materials are attractive because of their low cost, easy produce, good mechanical properties, and so forth. Among those alternatives unsaturated polyester is the characterization of high performance and operating at a fast rate (attractive) due to its dimensional stability, low price, and light weight [4). It belongs to the thermosetting group of polymers (hard and stiff cross linked material that does not soften or become moldable when heated). They offer exciting advantages from the viewpoint of there was widely applications [5]. A composite material whose reinforced by a particle and all the dimensions of particle approximately equal (equiaxed) is called particulate reinforced composites. polymers using fillers as a reinforcement whether inorganic or organic, is common in the field of production of modern polymeric dielectrics for improved discharge resistance, matching of the coefficient of thermal expansion, and higher thermal conductivity as well as mechanical reinforcement, abrasion and wear resistance and long-term mechanical behavior[6]. Polymer composites are manufactured commercially in many different applications such as sporting goods, aerospace components, automobiles, etc. and they are generally used for buildings, such as shower stalls, bathtubs, and imitation granite and cultured marble sinks [7]. The final properties of composites materials affected by several factors related to properties of matrix material and the reinforcement material properties such as the type, size and shape of the Particulate fillers and distribution within the matrix material and must be uniformly distributed [8], particle–matrix interfaces adhesion and particle loading. Particle size has an evident effect on these mechanical properties [9].There is several researchers doing for improving mechanical and physical properties for composite materials. A. A. Kareem (2013) studied the mechanical properties (tensile and flexural) of granite powder filled
- 4. Wasit Journal for Science & Medicine 2016: 9(3): (99-108) 010 polycarbonate (PC) toughened epoxy composites and the effect of the chemical resistance on these properties. The results showed good chemical resistance for the prepared composites and better mechanical properties was observed for composites reinforced with 20% granite [10]. S. M. Hassan et.al (2014) prepared (Epoxy – Granite) composite with different percent volume of Granite powder and investigated the effect of acid immersion on the hardness of composites. Hardness test was conducted for all samples in two conditions (normal condition and after immersion in HCL solutions for periods ranging up to 10 weeks .It was observed that the hardness increased with increasing the weight percent of granite, and Hardness values for the composites before immersion in HCL (1 M and 2 M) solutions are greater than values of composites after immersion [11]. Materials and Methods 1- Materials Used The materials used to prepare the composite samples are: 1- Unsaturated Polyester Resin (UPE) made by (SIR) company from Saudi Industrial Resin Limited with low viscosity, high reactivity and density from1 to1.3 g/Cm3 at 25°C. 2- Methyl ethyl ketone peroxide (MEKP) made in Jordan, the chemical formula (C8H16O4) and with specific gravity 1.17 is across linking (hardener) for an unsaturated polyester resin. 3- Granite particles made in Turkey with particle size (53µm). 2- Sample Preparation 1-To prepare pure specimens unsaturated polyester resin and thermally hardened which is Methyl Ethyl Keton peroxide (MEKP) was mixed by using the mechanical mixer, the weight ratio between hardener and resin was 2 gm of hardener per 100 gm of the resin at room temperature to form a strong permanent band converted to a solid state specimen by putting it in suitable template and after that all the specimens Left at room temperature about 24 hours to cure then placed after hardening in an electric oven in temperature of 60˚C for a period of 2 hours. This process is called fast treatment (post-curing) and after the completion of this process, the specimen becomes ready for a final examination. 2-The technique used to prepare the UPE/granite composites specimens was Hand lay-up, it is a simple way to use and can from which to obtain specimens of different shapes and sizes. UPE resin was mixed with granite; the contents were mixed thoroughly until homogeneous mixture was obtained, by using the mechanical mixer and then hardener (MEKP) was added to the mixture. Finally, they were cast in moulds, the specimen shape prepared for mechanical and physical test are identical to the specification of ASTM for each test. After that all the specimens Left in the room temperature about 24 hours to the cure and then for post-curing, the specimens were left for 2 hours in an electric oven at temperature 60˚C.Figure (1) shows all prepared specimens.
- 5. Wasit Journal for Science & Medicine 2016: 9(3): (99-108) 011 Figure (1): Shows the prepared specimens for testing. 3-Experimental Tests Tests such as, diametrical compression strength, hardness, thermal conductivity and dielectric strength, were carried out on micro composites. We have used in this research a set of devices for the purpose of testing the samples. For hardness (Shore D) has been taking at least three readings in different places of the specimen, while the other tests, it was examined at least three prepared specimens and the mean values were reported. In order to investigated the effect of granite microparticles on the mechanical and physical properties of the composites. 3-1 Diametrical Compression The use of diametrical compression test as a mechanical technology testing technique spanning many technological fields and used in estimating strength of the materials elastically deform, which are susceptible to brittle fracture. It was also known as the diametrical tensile test, Brazilian disc test, indirect tensile test, compact crushing test, or compact hardness test [12]. It allows for diametrical compressive test for the use of simple specimen geometry (disc, compact, tablet, etc.) to measure a limit force required to cause failure, which is used in the estimation of tensile strength which is given by the equation[1]. In the diametrical compression test, we assume that the tensile strength of the specimen can be expressed in terms of the maximum principal tensile stress in the specimen. Figure (2) shows the geometric shape of specimen and the method of load shedding. The diametrical compressive test was conducted for all specimens to determine the diametrical compressive strength by using equation (1) (12, 13), and the instrument from Gunt Hamburg company. Where is the diametrical compression strength (N/mm2) . is the maximum load (force at fracture) indicated by the testing machine (N) is the diameter of the specimen (40mm), and is the thickness of specimen(mm). Figure (2): Shows the geometric shape and the method of shedding the load on the specimen (16).
- 6. Wasit Journal for Science & Medicine 2016: 9(3): (99-108) 012 3-2 Hardness Hardness is another mechanical property that can be important to be considered, it is a measure of the resistance of the material to permanent deformation (bent, broken or shape change) or damage [14].Shore D Durometer Hardness was specific to measure the hardness of polymeric materials which thermally solidified (Thermosetting Polymer). It provides a very good idea about of material properties of the durability and cohesion of material mass and also by using small loads [15]. Hardness test was conducted for UPE/granite composites at different weight percentages (0, 5,10,15,20 and30) % to investigate the effect of granite particle on the hardness of prepared specimens by using Shore D Durometer Hardness tester fabricated by TIME GROUP INC Company was used to measure the hardness test by using the pointed dabbing tool. The pointed dabbing tool penetrates the material surface by the pressure applied on the instrument where the dabbing tool head touching quite the surface of the specimen then calculate the values hardness for the specimens through the penetration of the Durometer indenter foot into the specimen. 3-3 Thermal Conductivity Thermal conduction is the phenomenon by which heat is transported from high to low-temperature regions of a substance. So the property that characterizes the ability of a material to transfer heat is the thermal conductivity, the heat is transported by lattice vibration waves (phonons) and free electrons in solid materials. A thermal conductivity is associated with each of these mechanisms and the sum of the both two contributions gives the total conductivity (K=Kl+Ke). Thermal conductivity was carried out for all prepared specimens with the diameter (40 mm) by using (Lee's Disc) and applying equation [2](8,16). [ ] [ ( ) ] The value of (e) calculated from the equation [3] through knowing that the energy entering the heater equal energy outgoing [17). [ ] 3) Where K is thermal conductivity (W/m e is heat loss in (sec) in unit area (m2 ) and different in the temperature between discs and environment, d1, d2, d3 are thickness of the discs in(m), is the thickness of specimen in(m) , r is radius of the disc in (m),T1,T2,T3 is temperature at disc1,2,3 respectively in ( )and I is current throw the heater coil in Ampere and V is the voltage on the heater in Volt. 3-4- Dielectric Strength There are many properties of dielectrics are important such as dielectric constant, dielectric loss and dielectric strength (Breakdown Voltage), one of them is dielectric strength which represented the average potential per unit thickness at which failure of the dielectric material occurs the electric field magnitude that required for causing dielectric breakdown
- 7. Wasit Journal for Science & Medicine 2016: 9(3): (99-108) 013 is called the dielectric strength which can be determined from this formula by dividing the breakdown voltage at that particular point by the thickness of the sample at the same point as in equation [4](18),by using the dielectric strength instrument type (BAUR PGO S 3) Germany origin. Eb:r :is the dielectric strength and calculated in units: (Kv/sec.mm) Ubr: is the break down voltage in (Kv/sec) which represents the reading device and The values of diametrical compression strength, hardness, thermal conductivity and dielectric strength (breakdown voltage) together with their significances are summarized in Table (1). t: is the thickness of insulator. Table1: The values of some mechanical and physical properties for UPE and UPE/granite composites. Results and Discussion The plotted curve Figure (3) illustrated the diametrical compression strength of granite particles reinforced polyester composites as a function of the weight percentage (0, 5, 10, 15, 20, and 30) % of granite. As the data in Table (1) has appeared, the diametrical compression strength was increased from 3.24 to 7.02 N/mm2 for UPE and with addition of 30% granite particles, granite improved the diametrical compression strength by116.66% at 30% granite, this due to high degree of adhesion between the polymer molecules and granite particles, because the granite act as binding materials (19). as well as for this enhanced in the behavior of compression strength is due to the supposition role for reinforcement particles in obstruction the growth and progress of cracks and an increase in resistance of material to deformation. Figure (4) represented the variation of the shore hardness values with the weight percentage of granite particles; it shows that the hardness increased with increasing granite particles. It was increasingly nonlinear relations with the increase in the weighted percentage of granite particles but the rate of increase varies from one percentage weight to another. Specimen identifier diametrical compression strength(N/mm2 ) Hardness Thermal Conductivity (W/m. Dielectric strength (Kv/sec.mm) UPE 3.24 81.4 0.376 6.41 UPE/5%G 4.68 83.2 0.403 8.22 UPE/10%G 5.32 84.1 0.435 8.45 UPE/15%G 6.46 85.5 0.451 8.97 UPE/20%G 7.02 86.7 0.471 8.64 UPE/30%G 8.49 87.9 0.500 9.41
- 8. Wasit Journal for Science & Medicine 2016: 9(3): (99-108) 014 As the polymers have low hardness so the lowest value obtained for pure unsaturated polyester before reinforcement it was (81.4), while was (87.9) at the percent of granite particles (30 wt %). This is may be attributed to increasing the surface area of granite particles in contact with unsaturated polyester and decreasing the movement of polymer molecular which lead to the rise of the strength of the material to scratch and increasing of the material strength to plastic deformation [17]. The result is in good agreement with results obtained for unsaturated polyester resin reinforce with Fe weave wire (20), also agree with results obtained by Ahmed[05) which showed that a very high hardness for composites(AL-B4C)when increased percentage of boron carbide particles as compared to the hardness of aluminum matrix alone which was indicated a good interconnection between Aluminum matrix and boron carbide in addition carbide particles seems to work as barriers to the deformation of matrix material the foundation and inhibit the growth and progress of cracks when they occur, causing a significant increase in resistant material for high flow and an increase in the hardness. Figure (5) shows that thermal conductivity values increase when polyester resins fill by granite particles, From the results obtained thermal conductivity was increased from (0.376 W/m. ) for UPE to (0.403 W/m. ) at 5 wt. % granite particles and then increase from (0.435 W/m. ) at10wt% to (0.451 W/m. ) at 15 wt. % until reaches maximum value (0.5W/m. ) at 30 wt. % granite particles as shown in table (1),also the amount of the difference between the temperatures (T1 & T2) for the composite sample surfaces less as the weighted percentage increased. This is due to the surface area of the particles will be the larger and the interstitial spacing between the particles be less when percentage weight of the reinforcement increase and therefore have influence clear on thermal conductivity. In addition, the reinforcement material has a crystalline structure in which the atoms are arranged in accordance with the three- dimensional crystalline network (8). 0 1 2 3 4 5 6 7 8 9 0% 5% 10% 15% 20% 25% 30% 35% Diametrical Compression Strength(N/mm2) Wt.% of Granite Particles 81 82 83 84 85 86 87 88 89 0% 5% 10% 15% 20% 25% 30% 35% Shore.D(Hardness No.) wt.% of Granite Particles Figure (3): Diametrical compression strength vs. the weight percentage of granite particles for UPE/granite composites Figure (4) Hardness vs. the weight percentage of granite particles for UPE/granite composites
- 9. Wasit Journal for Science & Medicine 2016: 9(3): (99-108) 015 Figure(6) explain the change in the dielectric strength with granite content of UPE/granite composites, it observed the nonlinear relation between them , and the results reveal that UPE/granite composites produce improvement in dielectric strength due to the improved in compatibility between the matrix and reinforcement interface. It can be inferred from the table (1) the maximum values obtained of dielectric strength (9.41Kv/sec.mm) with weight percentage 30% of the added granite particles to the UPE it was increased about46.8% , but all the results obtained still higher than that of UPE as shown in figure (6) and table (1).So we can say the mechanism of the dielectric strength testing considered as one of the methods in which it examines the homogenization and dispersion of reinforcement material in the composite material (18). Conclusion Based on the results it was obtained following conclusions have been drawn: Composites can easily be made by hand lay-up technique. The composites materials properties depend on the particulate reinforced materials. From the experimental results, it is obvious that both of the mechanical and physical properties after reinforcement by granite particles will increase with increasing percentage of reinforcement. It is concluded that granite acts as binder materials and as particulate reinforcement materials results in improvement in the properties of unsaturated polyesters. 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0% 5% 10% 15% 20% 25% 30% 35% Thermal Conductivity(W/m.Cº ) wt.% of Granite Particles 5.0 6.0 7.0 8.0 9.0 10.0 0% 10% 20% 30% 40% Dielectric trength(kV/sec.mm) wt.% of Granite Particles Figure (5) Thermal conductivity vs. the weight percentage of granite particles for UPE/granite composites Figure (6) Dielectric strength vs. the weight percentage of granite particles for UPE/granite composites
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