Study of Mechanical and Electrical behavior of chemically treated coir fibre reinforced epoxy...

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International J.of Multidispl.Research & Advcs. in Engg.(IJMRAE), ISSN 0975-7074, Vol. 5, No. II (April 2013), pp. 171-180

STUDY OF MECHANICAL AND ELECTRICAL BEHAVIOR OF CHEMICALLY TREATED COIR FIBRE

REINFORCED EPOXY COMPOSITES

ALVEERA KHAN1, M. AYAZ AHMAD2, SHRISH JOSHI1 AND A. M. ABD EL-KHALEK2

1 Physics Department, Government MVM College Bhopal – 462001, India 2 Physics Department, College of Science, University of Tabuk – 71491,

Kingdom of Saudi Arabia

Abstract

In this paper an attempt has been made to study some mechanical and electrical properties of a

proposed composite polymer i.e. resin coconut fibres (which is identified as coir fibres). A volumetric

amount of coir fibre up to ≈ 15% was made-up and also it was arranged in arbitrarily oriented

discontinues fashion. In order to measure the mechanical characteristics on the coir fibre composite

due to the chemical treatment (Fe(NO3)3 and NH4Cl salts) various characterising tools such as SEM

and XRD are carried out to determine the strength of material. Finally, it was observed that the effects

of reinforcing epoxy matrix with the chemically treated coir fibres caused the composites to be more

rigid and not easy to deform due to high strain values and reduction of high resonant amplitude.

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Keywords : Natural coconut / coir fibres, SEM, and polymer composites.

PACS number: 84.37.+q, 72.80.Tm © http: //www.ascent-journals.com

172 ALVEERA KHAN, M. AYAZ AHMAD, SHRISH JOSHI AND A. M. ABD EL-KHALEK

1. INTRODUCTION

Natural fibres such as sisal, jute, coconut / coir, oil palm, flax, hemp, sun-hemp, ramie, kenaf

e.t.c. simply can be found in many tropical regions and are available throughout the world.

Today these fibres are careful as environment gracious materials owing to their

biodegradability and renewable characteristics. All natural fibres have been proved to be

good reinforcement in thermoset and thermoplastic matrices [1-4]. Nowadays, the use of

natural fibres reinforced composites is gaining popularity in automotive, cosmetic, and

plastic applications because it offers an economical and environmental advantage over

traditional inorganic reinforcements and fillers [5].

Here a study has been made in probing for such new material; by using coconut fibre (also

known as coir fibre) and also is compounded with composite material. Coir is the natural

fibre of the coconut husk where it is a thick and coarse but durable fibre. It is relatively

water-proof and has resistant to spoil by salt water and microbial degradation [6, 7]. An

outlook of skull of the coconut (natural fibre) has been depicted in Fig. 1, which can be used

as a source of fibre and coir pitch. For now, the investigation of the mechanical properties

and dynamic characteristics of the coir fibre reinforced epoxy composites is very important.

The use of coir fibre reinforced composites is essential in the industrial automotive where it

used to make seat cushions for Mercedes automobiles. Even though it has profitable

properties, the coir fibre composites still have some undesirable properties such as

dimensional instability, flammability which are not suitable for high temperature application

and degradability with humidity, ultraviolet lights, acids and bases [8, 9] (Brahim & Cheikh

2006). Therefore, a lot of efforts have been carried out to improve the performance of coir

fibre reinforced composites.

In this paper we have deliberate some characterization and performance of natural fibre

reinforced composite by analyzing the effect of fibre volume (%) on the composite

mechanical properties. The composites were obtained by compounding epoxy matrix and

coir fibres in a batch mixer to obtain a randomly oriented discontinue form. The selection of

epoxy as a matrix is based on economic interest because it offers a very cheap resin,

available with good mechanical properties and used in many purpose such as transport,

marine and sport.

STUDY OF MECHANICAL AND ELECTRICAL BEHAVIOR… 173

Figure 1 : An outlook of skull of the coir fibre (Natural fibre)

2. EXPERIMENT PERFORMANCE

The present experimental work has been performed as given in a flow chart. This flow chart

has been shown in Fig.2. The more details can be seen in our recent contribution submitted

by auothrs Alveera Khan et. al., to the journal of Mathematical Sciences International

Research Journal, ISSN 2278-8697-2013 [10].


Figure. 2 A flow chart for the performance of present experimental work.

3. RESULTS AND ANALYSIS

3.1 Scanning Electron Microscopy Analysis

The microscopy views have been taken out by SEM and are pictorially depicted in Fig. 3(a-

c). The description of this figure is as; (a) view for single time magnification by SEM for

chemically treated coir fibre (b), view of untreated coir fibre (c) for chemically treated coir

fibre reinforced epoxy composite. From these figures we have found that the treatment has

improved the surface roughness of the coir fibre when compared with untreated coir fibre.

This may be due to the lessening of fibre diameter which increases the feature ratio; thereby

developing a rough surface. Due to the elimination of the surface impurities and cementing

(a)

YES

Electrical properties obtained by Wayne Kerr impedance analyzer (65120B series for 20Hz - 120MHz)

Scanning Electron Microscopy (SEM) Analysis

Processing of coir fibre

Chemical treatment of coir fibre by Fe(NO3)3 and NH4Cl salts in ratio of 10:4 byannea with 500 ml of distilled water

Mixing of chemically treated coir fibre with epoxy resin and hardener in the ratio 1 : 1 : 1 (treated fibre : epoxy resin : hardener).Preparing specimen according to standard model

START

YES

Data analysis and plotting graph

END

YES NO

NO

NO

NO Success

YES

Success


materials like lignin and hemi-cellulose it can be found that separation of the definitive cells

has increased which show the way to boost up the surface area of the coir fibre so it becomes

more compatible with the matrix. It is also confirmed from the Fig. 3 (a and b) that the

adhesion between the fibre and matrix is poor in the raw coir fibre composite, as there are

gap around the fibre at the interface whereas, in the chemically treated composite, the fibre

matrix adhesion has been increased which is shown by fibre splintering rather than fibre

pullout in Fig. 3 (c). Similar behaviour has been found by other workers on SEM [11, 12].

Figure 3 : Scanning Electron Microscopy (SEM) investigations for (a) chemically treated coir

fibre (b) untreated coir fibre (c) chemically treated coir fibre reinforced epoxy composite epoxy-

fibre reinforced polymer composite (c).

(b) (a)

(c)


3.2 Flexural Strength Behavior

We have studied flexural strength behaviour for the pure epoxy composite and epoxy-fibre

reinforced polymer composite by UTM machine. This behavior for the above mentioned

fibres is shown in Fig. 4. From this figure it is evident that the strength of epoxy-fibre

reinforced polymer composite is found to be slightly higher than the pure epoxy composite.

It is also well recognized for reinforced polymer composites, that the interfacial zone

governs an important role in transferring the load between the fibre and matrix which

subsequently affect the mechanical properties such as strength. As we know that flexural

failure [13] depends mostly on the fibre and matrix adhesion, an increase the value of

flexural strength in chemically treated composite may be due to the increase in the efficient

surface area available for contact with the matrix [11, 14].

0

5

10

15

20

25

30

35

Epoxy fibre reinforcedChemical treatedcoir fibre

flexu

ral s

tren

gth

Figure 4 : Flexural strength behavior of chemically treated coir fibre

and epoxy-fibre reinforced polymer composite.

3.3 Electrical Properties

The electrical properties such as capacitative behavior (in pF) and dissipation factor, tanδ, (in

au) have been studied by using Wayne Kerr impedance analyzer [15] with measurement


accuracy up to ± 0.05%. The instrumental precision of impedance analyzing is within the

limit of 0 to + 40V dc (potential difference) and 0 to +100mA dc bias (electric current), multi

measurement mode, and equivalent circuit analysis option [15]. The test samples (present

work) were fixed between two electrodes and kept inside the sample holder. Two sets of

measurements for capacitative behavior and dissipative factor were carried out; from room

temperature around 300C to 2500C at two frequencies 1000 Hz and 5000 Hz with a heating

rate of 20C/min.

In order to get the mathematical values, we have used the following relations

(1)

(2)

where symbols represent their usual conventional value. Other properties of the composite

have been discussed at length elsewhere.

The dependence of capacitative behavior and dissipation factor (tanδ) on various

temperatures has been plotted graphically and has been shown in Figs. 5 to 6. From these

figures, it is evident that higher values of capacitance and dissipation factor at the lower

order of range of frequency, which is may be due to interfacial polarization.

0 30 60 90 120 150 180 210 240

10

20

30

Cap

acit

ance

(p

F)

Temperature (0C)

Frequency 1000 Hz 5000 Hz

Figure 5 : Behavior of Capacitance (pF) on temperature for frequency 1000 Hz and 5000 Hz.


40 80 120 160 200 240

0

2

4

6

8

tan

δδ δδ

Temperature (0C)

Frequency 1000 Hz 5000 Hz

Figure 6 : Dependence of dissipation factor (tanδδδδ), (in au) on temperature for frequency 1000

Hz and 5000 Hz.

Further, it is also clear from the above figures that the capacitance as well as the ‘tanδ’

values are first found to decrease with rise in temperature up to 40°C and then the values of

both the above factors are slightly increased approximate linearly for both the order of

frequencies. Similar results are also reported by various polymer physicists [16, 17]. These

results may facilitate to maintain the electric charges over a longer time period and also can

be browbeaten for antistatic applications.

4. SUMMERY AND CONCLUSIONS

On behalf of experimental investigation of mechanical behaviour of coir reinforced epoxy

composites one can the following conclusions:

* In the present work the flexural behaviour and electrical properties has been studied and

we have find a good agreements with the other’s worker.

* This work shows that successful fabrication of a coir fibre reinforced epoxy composites

with different fibre lengths is possible by simple hand lay-up technique.

(a)


* It has been noticed that the mechanical properties of the composites such as micro-

hardness, flexural strength etc. of the composites are also greatly influenced by the fibre

loading.

ACKNOWLEGEMENT

The authors (M. Ayaz Ahmad and A. M. Abd El-Khalek) are highly grateful to Vice

Presidency for Graduate / Studies and Scientific Research at University of Tabuk, and

Ministry of Higher Education, Kingdom of Saudi Arabia for the kind financial assistance.

REFERENCES

[1] Verma I. K., Ananthakrishnan S. R., Krishnamoorthi S., Composite of glass/modified jute fabric and unsaturated polyester. Composites, 20, pp. 383, 1989.

[2] Joseph, K., Thomas, S., Pavithran, C., Effect of chemical treatment on the tensile properties of short sisal fiber-reinforced polyethylene composites, Polymer, 37, pp. 5139^15, 1996.

[3] Sreekala, M.S., Kumaran, M.G., Thomas, S., Oil palm fibers: morphology, chemical composition, surface modification and mechanical properties, Journal Applied Polymer Sci; 66, pp. 8-821, 1997.

[4] Geethamma, V.G., Mathew, K.T., Lakshmnarayanan, R. & Thomas, S., Composite of short coir fibers and natural rubber: effect of chemical modification, loading and orientation of fiber, Polymer, 39, pp. 1483, 1998.

[5] Murali, K., Mohana, K., Extraction and tensile properties of natural fibers: Vakka, date and bamboo, Composite Structures 77, pp. 288-295, 2007.

[6] Ray, D., Natural Fibres, Biopolymers and Biocomposites. Thermoset Biocomposite in Mohanty. Boca Ranton, Flourida: Taylor & Francis, 2005.

[7] Shaikh, A. A., Zachariah Oommenb, Sabu Thomasc, Dynamic mechanical analysis of jute fibre reinforced polyester composites, Composites Science and Technology, 63, pp. 283-293, 2003.

[8] Turtle, M. E., Structural Analysis of Polymeric Composite Materials, New York: Marcel Dekker Inc. 1-41, 2004.

[9] Brahim, S.B., Cheikh, R. B., Influence of Fibre Orientation and Volume Fraction on the Tensile Properties of Unidirectional Alfa-Polyester Composite, Composites Science and Technology, 2006.

[10] Alveera K., Ayaz M. A., Shrish J., Abd El-Khalek A. M., Synthesis and characterization of chemically treated fibre and its reinforced epoxy polymer composites, Paper submitted to conference “International Conference on Mathematics (ICM-2013)” to be held at Kochi, Kerala, India from August 9-10, 2013.

[11] Sushree Sangita Mullick, Master thesis entitled “Fabrication and charecterization of natural fibre reinforced polymer composites” at NIT, Rourkela, 2012.

[12] Rout J., Misra M., Mohanty A. K., Nayak S. K., Tripathy S. S., SEM observations of the fractured surfaces of coir composites, J. Reinf. Plast. Compos. 22, pp. 1083, 2003.


[13] Harish S, Michael D. P, Bansely A, Mohan Lal D. and Rajadurai A, “Mechanical property evaluation of natural fiber co ir composite”, Materials characterization, 60, pp. 44-49, 2009.

[14] Geethamma V. G., Kalaprasad G., Gabriel G., Sabu T., Dynamic mechanical behavior of short coir fiber reinforced natural rubber composites. Composites 36, pp. 1499–506, 2005.

[15] Wayne Kerr Electronics, full instrument information, www.waynekerrtest.com

[16] Hill C. A. S and Khalil H. P. S. A, “Effect of fiber treatments on mechanical properties of coir or oil palm fiber reinforced polyester composites”, Journal of Applied Polymer Science, 78 , pp. 1685, 2000.

[17] Amor I. B., Rekik H., Kaddami H., Raihane M., Arous M., Kallel A., J. of Electrostat 67, pp. 717-722, 2009.

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