investigation on thermal properties of epoxy composites filled with pine apple leaf fiber

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International Journal of Research and Innovation on Science, Engineering and Technology (IJRISET)

INVESTIGATION ON THERMAL PROPERTIES OF EPOXY COMPOSITES FILLED WITH PINE APPLE LEAF FIBER

Mallireddy Subramanya Pravallika1, Devadas Deepu2, Maddukuri Sarath Babu3.

1 Research Scholar, Department of Thermal Engineering, Aditya College of Engineering and Technology, Surampalem, Andhra Pradesh, India.2 Assistant Professor, Department of Mechanical Engineering, Aditya College of Engineering and Technology, Surampalem, Andhra Pradesh, India.3 PHD Scholar, Department of Mechanical Engineering, OPJS University, CHURU, Rajasthan, India.

*Corresponding Author:

Mallireddy Subramanya Pravallika,Research Scholar,Department of Thermal Engineering, Aditya College of Engineering and Technology, Surampalem, Andhra Pradesh, India.Email: [email protected]

Year of publication: 2016Review Type: peer reviewedVolume: III, Issue : I

Citation:Mallireddy Subramanya Pravallika, Research Scholar "Investigation on Thermal Properties of Epoxy Composites Filled With Pine Apple Leaf Fiber" Interna-tional Journal of Research and Innovation on Science, Engineering and Technology (IJRISET) (2016) 98-102.

INTRODUCTION

In general synthetic fibers like glass fibers, carbon fibers, nylon, wool etc. are the most widely used fillers for vari-ous applications as the structural components and wear resistance. In this Glass Fiber Reinforced Polymer (GFRP) composites are the most important materials in the field of Engineering, mainly because of their good specific stiff-ness, Strength along with their low density and also due to its lower thermal conductivity. But Glass fiber reinforced polymer composites have many disadvantages like they are toxic in nature and corrosive, high cost, non-recycla-ble, and also not bio-degradable. In the recent decades, due to the environmental responsiveness and Ecological concern attention towards Natural Fiber Reinforced com-posites (NRFC) has increased. These natural composites have many advantages including low cost, light weight, non-toxic, bio degradable etc., and also these natural fib-ers possess very less thermal conductivity which is lower than the synthetic fibers and used as filler material for various insulation applications.

As ‘Light weight’ is a Key in achieving national energy goals. Natural Fiber reinforced polymer composites are lightweight materials (33) having high strength, high stiff-ness when compared with the metal polymer composites. In Generation (1940s-1970s) development and massive use of carbon fiber as reinforcement in the composites are used in load bearing structures which replace the met-al composites. In generation (1980s-2010s), composites brought about a great use in aerospace, military, sport-ing goods etc. Now in the present generation there is a great use of Natural fiber reinforced composites (NFRC) because of their superior advantages over the synthetic fibers, i.e., there are relatively low weight, cost effective, less damage to processing, good mechanical and physical properties such as tensile strength and flexural strength, abundant, biodegradability and minimal health hazards.The present work is taken to investigate the effect of fiber volume fraction on the thermal properties of the PALF re-inforced polymer composites.

The main objective of the present work is to fabricate a new class of less weight, low cost polymer composites in which the pine apple leaf fiber is used as reinforcement to improve the insulating capabilities of Epoxy resins. Pine-apple leaf fiber is used as filler materials in the present investigation reinforced in the Epoxy resin to fabricate a new class of composite materials by using hand-layup techniques.

The thermal conductivity values of the composites with different volume fraction are calculated mathematically or experimentally using UNITHERM 2022 named as Gradu-ated Heat flow meter with varying temperature range from 30˚C to 150˚C. The Specific heat capacity values of the Epoxy composites are evaluated using Differential scan-ning calorimeter. And finally by numerical calculations the thermal diffusivity is evaluated and calculated.

Abstract

The present paper deals with the effect of volume fraction of fillers on the thermal Properties of polymer composites. This work sees an opportunity of enhancement on insulation capability of a typical fiber reinforced polymer composite. To validate this mathematical model, a set of epoxy based composites, with fiber content ranging 4.38 to 20.10% of volume fractions have been prepared by simple hand lay-up technique. For preparing the composite, natural fiber i.e. Pine ap-ple leaf fibers are incorporated in Epoxy Resin. Thermal conductivities of these composite samples are measured as per ASTM standard E-1530 by using the Unitherm™ Model 2022 tester, which operates on the double guarded heat flow principle at the temperature ranging from 30˚C to 150˚C. And also the Specific Heat of the powdered samples are meas-ured by using Differential Scanning Calorimeter (DSC). By using the MATLAB the numerical analysis is carried out to find the value of Thermal Diffusivity with varying temperatures. It was observed that the thermal diffusivity varies with fiber concentration, but the variation of thermal diffusivity with varying temperature was not so significant.

KEYWORDS: Pine Apple Leaf fiber, Epoxy Composites, Volume Fraction, Thermal Properties.

International Journal of Research and Innovation in Thermal Engineering (IJRITE)

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MATERIALS AND METHODS:

MATERIALS

Matrix material-1

The Matrix Material used is the Epoxy (LY 556). It pro-vides a solvent free curing system when it is combined with the hardener Tri-Ethylene Tetra mine (TETA) which is an aliphatic primary amine with commercial designa-tion HY 951 for the polymer composites.

Properties of Epoxy (LY 556) Resin

SL.NO Characteristic Property Inferences

1 Density 1.1gm/cc

2 Compressive Strength 90 MPa

3 Tensile Strength 58 MPa

4 Thermal Conductivity 0.363W/mK

5 Electrical conductivity 0.10 × 10-16 S/cm

Filler Material Extraction

The Extraction of Pine Apple Leaf Fiber (PALF) is obtained by using decorticator machine. This machine is used to separate the fiber from unwanted dirt particles present. This machine is powered by a 20HP diesel Engine. This extracted fiber is dried in a solar dryer to reduce the Mois-ture content in the fiber. Initially, the moisture content present in the PALF after the extraction is about 60 to 70%. The fiber is dried in the solar house for 3 to 4 days to attain 15% moisture content.

Pine Apple leaf

Pine Apple leaf Fiber (PALF)

Properties of Pineapple Leaf Fiber (PALF)

SL.NO Characteristic Property Inferences

1 Density 1.5gm/cc

2 Young’s modulus 34.5–82.51Gpa

3 Tensile Strength 413–1627MPa

4 Thermal Conductivity 0.0273W/mK

EXPERIMENTAL DETAILS

Fabrication of Composites

Using the hand layup method, the Low temperature cur-ing epoxy resin (LY 556) (commonly known as Bisphenol-A-Diglycidyl-Ether) and corresponding hardener (HY951) are mixed in a ratio of 10:1 by weight as recommended. Two identical specimens are prepared, which are used for finding the Thermal Conductivity and other is grinded as a fine powder using the grinding machine to find the Spe-cific Heat. In the Similar way Six identical sets of Speci-mens are prepared for finding the thermal properties of specimens with varying fiber Volume fraction as shown in the following table .

For finding the Thermal Conductivity

Sample Composition (Epoxy Resin)

1 Epoxy+ 0% of PALF

2 Epoxy+4.38% of PALF

3 Epoxy+ 9.50% of PALF




Calculations of Densities and Volume Fractions of Fib-ers:

The important property of a light weight material is the Density of the material. If the density of the material is low then the weight of the material is less. To calculate the densities of the material firstly we need to know the volume fraction of the filler and the matrix.

For finding this we are using the formulae

Where, FVF = Fiber Volume FractionFWF = Fiber Weight Fractionρf = Density of Filler, kg/m3

ρm= Density of Matrix, kg/m3

And now the density of the composites are measured us-ing the following equationρc=ρfVf+ρmVm

Where, ρc = Density of Composite, kg/m3

ρf = Density of Filler(PALF Fiber), kg/m3

Vf= Volume of Filler, m3

ρm= Density of Matrix, kg/m3

Vm= Volume of Matrix, m3

Here Vf=FVF×100, and Vm=MVF×100Where, MVF= Matric volume fraction

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The following tables shows the values of Fiber Volume fraction and densities of two set of PALF Reinforced com-posites

The following table shows the values of Fiber Volume Fraction and Densities of PALF Reinforced Epoxy Com-posites.

Fiber Volume Fraction and Densities of PALF Reinforced Epoxy Composites

Sam-ple

Mass, m (g)

Den-sity of Matrix, ρm (g/cm3)

Den-sity of Filler, ρf (g/cm3)

Fiber Vol-ume Frac-tion, FVF

Volume of filler, Vf %

Density,ρc (g/cm3)

1 20 1.1 1.5 0 0 1.1

2 22.85 1.1 1.5 0.0325 3.25 1.11

3 21.5 1.1 1.5 0.0715 7.15 1.13

4 21.5 1.1 1.5 0.1106 11.06 1.14

5 21.35 1.1 1.5 0.1443 14.43 1.16

6 19.9 1.1 1.5 0.1557 15.57 1.16

THERMAL CONDUCTIVITY CHARACTERIZATION

For finding the thermal conductivities of Unknown spec-imens the following formulas are used after getting the readings from the Graduated heat flow meter.At thermal equilibrium, the Fourier heat flow equation applied to the test stack becomes

R=F[Tu-Ti]/Q -RintWhere R = Thermal resistance of the sampleF= Heat flow transducer calibration factor (HFT)Tu = Upper plate surface temperatureTi = lower plate surface temperatureQ= Heat flow transducer outputRint = Interface thermal resistance

The sample thermal conductivity (k) is calculated fromR x/kWhere, x= Sample thicknessq=∆T/RWhere, q= Heat flux, W/m2

∆T = Change in Temperature, KQ=q×AWhere, Q= Heat Flow, WA= Area, m

Specific Heat Capacity

The specific heat capacity of the PALF reinforced Epoxy composites are measured using the Differential scanning calorimeter. For finding these values we need to consider the powdered form of the composites at the heating rate of 5˚C/min.

Thermal Diffusivity

The value of thermal diffusivity of the PALF reinforced epoxy composites are calculated using the following for-mula. It has the SI unit of m²/s. Thermal diffusivity is usually denoted α. The formula is:

α=k/(ρ×Cp)

RESULTS AND DISCUSSIONS:

Thermal Conductivity of PALF Reinforced Epoxy compos-ites with varying temperatures:

Thermal Conductivities of PALF reinforced Epoxy composites with varying temperature change, W/mK

Sam-ple

Volume Frac-tion of Fiber(Vf)%

k at 30˚C

k at 60˚C

k at 90˚C

k at 120˚C

k at 150˚C

1 0 0.246 0.243 0.265 0.28 0.3

2 3.25 0.223 0.235 0.246 0.266 0.274

3 7.15 0.212 0.222 0.231 0.249 0.262

4 11.06 0.206 0.219 0.221 0.234 0.248

5 14.43 0.188 0.201 0.213 0.224 0.231

6 15.57 0.179 0.192 0.201 0.216 0.223

By observing the Values of thermal conductivity of PALF Reinforced Epoxy composites with varying fiber volume fraction, it is clear that the thermal conductivity values

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decreases as the fiber volume increases. And also we can observe that with the increase in temperature range the thermal conductivity of the composites increases but there is only a small change in those values. So as a re-sult it can be used as an insulating material, and due to its low density values it can used as a lightweight material as a replacement for carbon fiber Reinforced Epoxy com-posites which are widely used in Military and Aerospace applications.

Specific Heat Values of PALF Reinforced Epoxy Com-posites

Specific heat Capacities of PALF reinforced Epoxy composites with varying tem-perature change

Sam-ple

Vol-ume of Fiber, Vf %

Cp at 30˚C Cp at 60˚C Cp at 90˚C Cp at 120˚C

Cp at 150˚C

1 0 2028.393 2003.6565 2185.0575 2308.74 2473.65

2 3.34 1609.406 1696.0109 1775.398 1919.74 1977.477

3 7.33 1626.089 1702.791 1771.8237 1909.887 2009.601

4 11.33 1580.067 1679.78 1695.1213 1794.8344 1902.218

5 14.88 1452.134 1552.5484 1645.2379 1730.203 1784.273

6 15.93 1483.361 1591.091 1665.672 1789.9778 1847.986

From the above figure, it is clearly observed that as the temperature increases the specific heat value increases. And with the increase in fiber volume fraction the specific heat capacity decreases.

Thermal Diffusivity of PALF Reinforced Epoxy CompositesThe thermal diffusivity of the PALF reinforced Epoxy Com-posites was determined by the temperature change from 30˚C to 150˚C with varying fiber concentration as shown in the Table

Thermal Diffusivity(α) of PALF reinforced Epoxy composites with varying Tempera-ture

Sam-ple

Vol-ume of Fiber, Vf %

α*10-7 at 30˚C

α*10-7 at 60 ˚C

α*10-7 at 90 ˚C

α*10-7 at 120 ˚C

α*10-7 at 150 ˚C

1 0 1.0936 1.0946 1.0966 1.0936 1.0976

2 3.25 1.248 1.249 1.247 1.2492 1.249

3 7.15 1.1533 1.1538 1.15275 1.15785 1.1523

4 11.06 1.1443 1.14563 1.14463 1.14163 1.14263

5 14.43 1.11507 1.11607 1.11707 1.116 1.1117

6 15.57 1.04027 1.04037 1.04127 1.04227 1.04127

By the above tables it is clearly observed that the varia-tion in thermal diffusivity with respect to change in tem-perature is negligibly very small but increase as the tem-perature increases and with the increase in fiber content the thermal diffusivity decreases.

CONCLUSION:

In this work, six sets of PALF reinforced Epoxy compos-ites were successfully developed with varying fiber volume fraction and their thermal properties such as Thermal conductivity (k), Specific Heat Capacity (Cp), and Thermal Diffusivity (α) were studied. From the above results it can be concluded that.

► As the fiber volume fraction increases the density of the PALF Reinforced Epoxy composites increases. And the density value varies from 1130 to 1160Kg/m3.

► With the increases in fiber volume fraction, the thermal conductivity of the composites decreases and the values varies from; as a result we can use as insulating materi-als. At the maximum volume fraction of fiber, the ther-mal conductivity of the PALF reinforced epoxy composites has varied from 0.179 Wm-1K-1 to 0.223 Wm-1K-1 in the temperature range 30 ˚C to 150˚C.

► The values of specific heat capacity for PALF rein-forced Epoxy composites varies from 1483.361 JKg-1K-1 to 1847.986 JKg-1K-1 in the temperature range 30 ˚C to 150˚C.

► The values of thermal diffusivity for PALF reinforced Epoxy composites vary from 1.04027*10-7m2/sec to 1.04127*10-7m2/sec in the temperature range 30 ˚C to 150˚C.

► From all these results, we can concludes that PALF re-inforced Epoxy composites are light weight, cost effective and possess good thermal insulating properties. Hence, these newly developed composites can be used for the ap-plications such as Aircraft and military, Space, automo-tive, Sporting Goods, Marine, and Infrastructure etc. as a replacement for Carbon Fiber epoxy composites and other metal Composites.

ACKNOWLEDGEMENT & DECLARATIONS:

I would like to express my sincere gratitude towards my projects advisor Mr. D Deepu Assistant Professor, Depart-ment of Mechanical Engineering, Aditya College of Engi-neering and Technology, Surampalem, AP, India, for his continuous support, generous guidance, help and useful suggestions. I would like to place on record my deep sense of grati-tude to Mr. M Sarath Babu, PHD Scholar, Department of Mechanical Engineering, OPJS University, CHURU, Ra-jasthan, India, for his stimulating guidance, continuous

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encouragement and supervision throughout the course of present work.I also wish to extend my thanks to Mrs. A. Rama Vasan-tha, Assistant Professor, Department of Electronics and Communication Engineering, Aditya College of Engineer-ing and Technology, Surampalem, AP, India, for her help in the numerical calculations and constructive sugges-tions to improve the quality of this work.

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AUTHORS

Mallireddy Subramanya Pravallika, Research Scholar, Department of Thermal Engineering, Aditya College of Engineering and Technology, Surampalem, Andhra Pradesh, India.

Devadas Deepu,Assistant Professor, Department of Mechanical Engineering, Aditya College of Engineering and Technology, Surampalem, Andhra Pradesh, India.

Maddukuri Sarath Babu.PHD Scholar, Department of Mechanical Engineering, OPJS University, CHURU, Rajasthan, India.

investigation on thermal properties of epoxy composites filled with pine apple leaf fiber

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