International Journal of Engineering Trends and Technology (IJETT) – Volume 15 Number 8 – Sep 2014
Experimental Investigation of Thermal Properties
of Borassus Flabellifer Reinforced Composites and
Effect of Addition of Fly Ash
1
Eeday.Saranya, 2 Goteti.Satyanarayana , 3Anne.SrihariPrasad
1,2,3
Mechanical Department, KL University
Guntur, India
Abstract— The objective of this study is to examine the
variation in thermal conductivity , specific heat capacity and
thermal diffusivity of composites with respect to fiber content,
temperature and fly ash content .The fly ash content is varied
from 10 to 30 % and with a temperature range between 30oC
to 120oC .The Composites with and without fly ash have been
prepared with Borassus (Toddy Palm) fibers as reinforcement
in polyester matrix. The primary derivative thermo grams of
the fibers were recorded in an inert atmosphere at a heating
rate of 20 0C / min. The experimental results of thermal
conductivity (K) of a
unidirectional fiber reinforced
composites were investigated by a guarded heat flow meter
method , specific heat capacity (Cp) of the composite is
measured by differential scanning calorimeter and thermal
diffusivity (α ) are studied with varying temperatures and fly
ash content .
Keywords—: Thermal conductivity (K) , Thermal
diffusivity ( α) , Specific heat capacity (Cp),
Graduated heat flow meter,
Fly-ash , Differential
scanning calorimeter (DSC)
I.
Introduction
Natural fibers have played a significant role in human
civilization since prehistoric times. The human beings
depend on them for garments and other simple domestic
uses as well as complex applications such as land dwellings
and reed-built sailing craft etc .The natural fiber –reinforced
composite had the advantage of being light, strong, cheap,
non abrasive, high specific mechanical and thermal
properties and are more environmental friendly. However
these have some drawbacks such as brittleness, moisture
absorption and low processing temperatures [2] .
Thermoplastic polymers especially polypropylene are
produced and used today in vast quantities. However, they
are seldom used as pure polymers and are usually combined
with mineral fillers like fly ash, graphite etc. Fillers find
application in the polymer industry almost exclusively to
improve thermal and mechanical properties. Fly ash is finely
divided mineral residue resulting from combustion of coal
in power generation plants. Fly ash mostly consists of SiO2,
Al2O3 and Fe2O 3 are present in inorganic incombustible
matter present in coal that has been fused during combustion
to glassy amorphous structure. Fly ash used in cement
industry could be used as filler in plastic products and
ISSN: 2231-5381
depending upon the source of coal contain elements like
carbon, titanium, magnesium etc. So the fly ash has been
added (10-30 g).
The properties of composites mainly depend on the matrix,
fibers, and other interfacial bonding. Several investigators
have used natural fibers as reinforcement in the
development of green composites.[3-5]The adhesion between
the reinforcing fibers and the matrix in composite material
plays an important role in final thermal properties of the
composites .
More recently, fiber reinforced resin
composites that have high strength –to-weight and stiffness
– to –weight ratios have become important in weight –
sensitive applications such as aircraft and space vehicles,
energy saving in connection with automobile air
conditioning has become more important thus the study of
effect of temperature on thermal properties of fiber
reinforced composites used in the automotive industry is
important.The use of thermal insulation materials has
increased significantly in recent years so this is a new
insulation material for low temperature thermal systems .
Currently various researchers and material scientists all over
the world are focusing their attention on thermo physical
properties of natural fiber –reinforced polymer composites.
Vegetable fibers can be extracted from
different parts of the plants such as stems, leaves, roots,
fruits, and seeds. To identify new natural fibers for use as
reinforcements, their thermal and mechanical behavior has
to be characterized. In the present work we have
characterized the behavior of Toddy palm fibers subjected
to thermal and mechanical loads to assess their suitability as
reinforcements. The Borassus (Palmyra Palm ) is a genius
of six species of fan palms, native to tropical regions of
Africa, Asia and new guinea. They are tall palms, capable
of growing up to 30m high. The leaves are long, fan shaped,
2to 3 m in length. The flowers are small, in densely
clustered spikes, followed by large, brown, roundish fruits.
Because it is a fiber new to composite research we studied
some of its properties such as thermal diffusivity, thermal
conductivity, and specific heat capacity. The effect of
Borassus on these properties was investigated and the
results are reported in this article.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 15 Number 8 – Sep 2014
With And Without Added Fly Ash Samples. Fig. 3
2.3 SPECIFIC HEAT CAPACITY MEASUREMENT
(Image courtesy by www.wikiepedia.org/wiki/file:Borassus
flabellifer:jpg.)
Fig. 1
Specific heat capacity is one of the most important
thermodynamic properties of the engineering materials. The
specific heat capacity of samples was measured using
differential scanning calorimeter (TA Instruments, Model
no, Q20) at a heating rate of 20°c/min.
II .MATERIALS AND METHODS
2.4 THERMAL CONDUCTIVITY MEASUREMENT
2.1 EXTRACTION OF FIBERS:
The extraction of fibers involves the retting process
followed by decorticating. The stems of toddy palm were
cut at their base and immersed in a water-retting tank for
two weeks. Then they are removed, The fibers were stripped
from the stalks by hand, washed and dried in the sun. After
drying, any extraneous matter that may still be adhering to
them was removed .then the fibers are treated with 5%
aqueous NAOH solution.
The graduate heat flow meter test method was used to
measure the thermal conductivity of toddy palm fiber using
Unitherm Model 2022 instrument in accordance with
ASTM-E-1530.
2.5 THERMAL DIFFUSIVITY
The physical significance of thermal diffusivity is associated
with propagation of heat in to the medium during changes of
temperature with time, the smaller the thermal diffusivity
the more time required for heat to generate the solid thermal
diffusivity (α ) is a function of thermal conductivity (k) and
specific heat capacity (Cp) can be calculated from the
relation given below and the results are presented in the
below tables.
α = K / ρ . Cp
III. RESULTS:
Fig. 2
TABLE: I. THERMAL PROPERTIES OF TODDY PALM WITH
OUT FLY ASH:
2.2 DENSITY OF FIBERS
The density of fibers is measured by the gravimetric method
.In general the density of natural fibers is depend on the
process of extraction , algae of plant, moisture present in the
fiber, soil condition in which the plant has grown , and
similar factors. The density of toddy palm fiber is (1007.87
kg/m3).
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Temperature Thermal
Specific
conductivity heat
capacity
( oC ) (W/M.K)
( KJ/KG.K)
Thermal
diffusivity
x 10-5
(m2/ sec )
30
0.142
1.029
5.3678
60
120
0.157
0.160
2.354
2.710
6.322
5.857
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International Journal of Engineering Trends and Technology (IJETT) – Volume 15 Number 8 – Sep 2014
TABLE: II. THERMAL PROPERTIES OF TODDY PALM
WITH FLY ASH 10 % :
Temperature Thermal
Specific
conductivity heat
capacity
( oC )
(W/M.K)
(
KJ/KG.K)
Thermal
diffusivity
x 10-5
(m2/ sec )
30
0.231
2.023
8.96952
60
0.292
2.965
9.3068
120
0.294
2.688
2.70834
TABLE: III. THERMAL PROPERTIES OF TODDY PALM
WITH FLY ASH 20 % :
Temperature Thermal
Specific
conductivity heat
capacity
( oC )
(W/M.K)
(
KJ/KG.K)
Thermal
diffusivity
x 10-5
(m2/ sec )
TABLE: V .CRITICAL RADIUS OF INSULATION FOR
DIFFERENT MATERIALS:
MATERIALS
CRITICAL RADIUS OF
INSULATION
(mm)
Glass wool
16.4
Toddy palm
56
Asbestos
61
The results show that toddy palm fibers can be used as
reinforcement in thermoplastics .Thermal conductivity ,
diffusivity and specific heat capacity were measured with
addition of fly ash and without addition of fly ash and then
reported in tables. Table I reveals that variation of thermal
conductivity, specific heat capacity with respect to
temperature for composites without fly ash is increasing,
where as thermal diffusivity is increasing and then
stabilized. table II , III, IV ,reveals that variation of thermal
conductivity with respect to temperature is with fly ash is
decreasing where as specific heat capacity is increasing and
thermal diffusivity is also increasing and then stabilized
.This may be due to reduction on moisture content of the
fiber. The results reveal that toddy palm fiber acts as a
thermal insulating reinforcement component in the
development of insulating green composites and with
addition of fly ash as a filler material the properties are still
more increasing with respect to temperatures.
IV. THEORETICAL DISSCUSION:
30
0.214
2.238
6.22728
60
0.249
3.172
7.34497
120
0.236
4.259
5.22750
TABLE: IV. THERMAL PROPERTIES OF TODDY PALM
WITH FLY ASH 30 % :
Temperature Thermal
Specific
conductivity heat
capacity
( oC ) (W/M.K)
(
KJ/KG.K)
When a solar water heating system of 2000lpd capacity is
considered with storage of 2000 lit tank , water is
maintained at 80oC throughout the night , the tank is made
of M.S plate of 5 mm thickness and all sides are insulated
with 100 mm mineral wool insulation, generally the outer
cover is made of either thin sheet (0.6 M.S) or Aluminum
.These are not structurally stable and suspect -able to
corrosion, the regular maintenance is required for these
materials by the way of painting M.S sheet or replacing the
aluminum cover.
Thermal
diffusivity
x 10-5
(m2/ sec )
If the outer cover is made of toddy palm composite
sheet of 1-2 mm thick the maintenance cost is nil. It can
withstand environmental conditions.
30
0.177
2.053
7.92199
60
0.277
3.135
8.11916
It is hoped that if the material is commercialized the cost of
toddy palm fiber at much cheaper prize than the glass fiber.
So, the overall cost of the material will be less than the
present composite material M.S sheet or Aluminium.
120
0.261
4.593
5.36050
Heat- transfer is maintained slightly less than M.S and
Aluminum sheets.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 15 Number 8 – Sep 2014
If the material is used in prefabricated form the critical
radius will be in between asbestos and glass wool which are
very common insulating material for insulating pipes shown
in the table V.
V. GRAPHS
and reported. The results showed that the toddy palm fiber
acts as a Thermal insulating reinforcement component in
development of insulating green composites .This toddy
palm composites doesn’t require any corrosion or painting
so, longer life is achieved and also can be pre- fabricated in
to different shapes and installation time required will be also
less. Hence toddy palm fibers are favorable reinforcing
materials for the development of load –bearing light weight
materials.
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VI.CONCLUSIONS
The fibers were extracted from palm tree by retting process.
The Thermal properties of the fibers such as Thermal
conductivity, Specific heat capacity and Thermal diffusivity
are measured with and without addition of fibers were tested
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