influence of stacking sequence on mechanical properties of basalt-jute fiber-reinforced polymer...

DOI 10.1515/polyeng-2012-0063 J Polym Eng 2012; 32: 547–554

Pandian Amuthakkannan * , Vairavan Manikandan , Jebbas Thangaiah Winowlin Jappes and

Marimuthu Uthayakumar

Influence of stacking sequence on mechanical properties of basalt-jute fiber-reinforced polymer hybrid composites

Abstract: Different stacking sequences of woven basalt

and jute fiber hybrid composites were prepared using

compression molding techniques. The static mechanical

properties such as tensile, flexural, and impact behaviors

were studied. A constant pressure was applied to all the

fabricated composites, and fibers were arranged in dif-

ferent layering patterns. It was found that from the differ-

ent layering patterns, the tensile and flexural properties

slightly increased for hybrid composites having alternate

layers of basalt and jute fiber. To study the fracture surface

morphology of the hybrid composites, scanning electron

microscopy was also performed.

Keywords: basalt fiber; hybrid composites; jute fiber;

mechanical properties; scanning electron microscopy

(SEM).

*Corresponding author: Pandian Amuthakkannan, Department of

Mechanical Engineering , Kalasalingam University, Krishnankoil 626

126 , India , e-mail: [email protected]

Vairavan Manikandan: Department of Mechanical Engineering ,

Kalasalingam University, Krishnankoil 626 126 , India

Jebbas Thangaiah Winowlin Jappes: Department of Mechanical

Engineering , Kalasalingam University, Krishnankoil 626 126 , India

Marimuthu Uthayakumar: Department of Mechanical Engineering ,

Kalasalingam University, Krishnankoil 626 126 , India

1 Introduction Composite materials produced today for hulls, surfboards,

sporting goods, swimming pool linings, building panels,

and car bodies, i.e., fiber-reinforced resin composites that

have a high strength-to-weight and stiffness-to-weight,

ratio have become important in weight-sensitive applica-

tions. Czig á ny [1] made a comparative study of hybrids of

carbon and basalt fibers with polypropylene matrix. To

achieve sufficient interfacial adhesion, the fibers were

treated with a reaction mixture of maleic acid anhyride

and sunflower oil. The strength of the hybrid composites

improved by surface treatment, and this was proven by

mechanical tests and microscopic analysis. An acoustic

emission test also carried out using a suitable microphone

to find the mode of failure. The results showed that the

basalt-carbon fiber hybrid has a significant improvement

in static properties over monocomposites and over basalt

and hemp fiber. Jawaid et al. [2] investigated the trilayer

hybrid composites of palm oil empty fruit bunches (EFBs)

and jute fiber prepared using palm oil EFB as the skin

material and jute as the core material, and vice versa . A

remarkable reduction in the void content of hybrid com-

posites in different layering patterns and a slight increase

in tensile property were observed for the composite

with jute as the skin and palm oil EFB as the core mate-

rial. Padma Priya and Rai [3] experimentally analyzed

the degree of mechanical reinforcement that could be

obtained by the introduction of glass fibers in biofiber

(silk fabric)-reinforced epoxy composites. The addition of

a small amount of glass fabric to the silk fabric-reinforced

epoxy matrix enhances the mechanical properties of the

resulting hybrid composites. It has also been observed

that the properties increase with an increase in the weight

fraction of reinforcement content to the maximum extent.

The water uptake of hybrid composites was observed to

be lower than that of unhybridized composites. Woven

coir-glass hybrid polyester composites were developed,

and their mechanical properties were evaluated for differ-

ent stacking sequences. These results indicated that coir-

glass hybrid composites offer the merits of both natural

and synthetic fibers [4] .

Basalt-carbon fiber hybrids with alternate stack-

ing sequences reinforced with epoxy composites have

been developed to improve the toughness properties of

conventional carbon fiber-reinforced composite materi-

als. The experimental results confirm that hybrid com-

posites containing basalt fibers display a 46 % higher

open-hole compression strength than plain carbon fiber

composites. Hybrid composite laminates are also less

sensitive to open holes compared with plain carbon

fiber composite laminates [5] . Hybrid friction materi-

als were manufactured using ceramic and basalt fibers.

The friction coefficient of these materials increases

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548 P. Amuthakkannan et al.: Basalt-jute fiber-reinforced polymer hybrid composites

with increasing additional basalt fiber content, but the

specific wear rates of the composites decreased up to

30 vol % of fiber content and then increased. The wear

tests showed that the coefficient of friction decreases with

increasing load and speed but increases with increasing

disc temperature up to a maximum of 300 ° C [6] . Aramid

fiber-ultrahigh-modulus polyethylene fiber interply hyb rid

composites were fabricated with changes in the stacking

sequence. The flexural strength and modulus of the hybrid

composites were measured to investigate the effect of stack-

ing sequence [7] . Aramid fiber-glass fiber hybrid composites

were prepared to examine the compressive performance of

impacted composites. The effects of the stacking sequence

and surface treatment on the compression after the impact

performance of the three-layer hybrid composites were

investigated with respect to the delamination area. As the

impact velocity increased, the laminates exhibited a signif-

icant reduction of compressive strength owing to a larger

delamination area within the laminate [8] . Amico et al.

[9] and Mariatti et al. [10] studied the mechanical pro-

perties of pure sisal, pure glass, and hybrid sisal-glass com-

pression-molded composites in which various stacking

sequences of fiber mat layers were used. Results showed

that the hybridization originated a material with general

intermediate properties between pure glass and pure

sisal. However, the importance of controlling the stack-

ing sequence to enhance properties was evident. Accord-

ing to Kuan et al. [11] , the mechanical properties of com-

posites based on self-reinforced polypropylene and glass

fiber-reinforced PP have been investigated. The repeated

low-velocity impact responses of hybrid plain-woven com-

posite panels were studied by drop-weight experiments.

The effects of hybridization and lay-up sequence on the

repeated drop-weight impact responses of woven compos-

ites were investigated. It was observed that damage accu-

mulations could be slowed down using hybridization. It

was also observed that the lay-up confi guration of a hybrid

composite had a significant influence on damage accumu-

lation rate. Hybrid specimens with glass-epoxy skins sur-

vived double the number of successive impacts compared

with hybrid specimens with graphite-epoxy skins [12] .

There are two types of fibers that are used as reinforce-

ments: natural and synthetic fibers. A lot of work has been

done on composites based on these fibers [13 – 17] .

In the present work, the mechanical properties of

polyester-based woven basalt and jute fiber-reinforced

hybrid composites have been studied with different stack-

ing sequences to concentrate the effect of layering differ-

ent fibers. The interaction between the reinforcement and

the matrix was studied by observing the fracture surface

of composites using scanning electron microscopy (SEM).

Sample particulars Basalt fiber Jute fiber

Moisture content ( % ) 0.15 9.58

Density at room temperature (g/cm 3 ) 2.64 1.347

Diameter of fiber (mm) 0.0166 0.4497

Mean breaking strength (G) 1644.4 1570.75

CV of strength ( % ) 13.6 26.97

Mean elongation ( % ) 1.15 1.56

CV of elongation ( % ) 13.37 16.91

Table 1 Properties of basalt fiber (single yarn).

Appearance Pale yellowish clear liquid

Viscosity at 25 ° C 500 – 600 cP

Volatile content 34 % – 36 %

Acid value 23 – 27 mg KOH/g

Density at 25 ° C 1.12 – 1.13

Cross-linking mixture 1.5 % catalyst and 1.5 % accelerator

Gel time at 25 ° C 15 – 25 min

Tensile strength 50 N/mm 2

Elongation at break 1.8 %

Flexural strength 110 N/mm 2

Table 2 Typical properties of the unsaturated polyester resin.

2 Experimental details

2.1 Materials

The basalt fibers were supplied by ASA. TECH, Ohlsdorf,

Austria. The jute fibers were supplied by S. N. Broth-

ers (Cochin, Kerala, India). Polyester resin, methyl ethyl

ketone peroxide (MEKP), and cobalt napthenate were pur-

chased from Sakthi Pvt. Ltd. (Tamilnadu, Chennai, India).

The properties of basalt and jute fibers are presented in

Table 1 , and the property of polyester resin is shown in

Table 2 .

2.2 Fabrication of composites

Basalt fiber-jute fiber-reinforced polymer matrix com-

posites were fabricated using compression molding tech-

niques of a uniform pressure without heating. A general-

purpose polyester resin was used as the matrix, and a

plain weave of 220 g/cm 3 woven basalt and jute fibers was

used as composite. For a proper chemical reaction, cobalt

napthenate and MEKP were used as the accelerator and

the catalyst, respectively. The curing of the polyester resin

was done by incorporating 1.5 vol % MEKP catalyst with



P. Amuthakkannan et al.: Basalt-jute fiber-reinforced polymer hybrid composites 549

1.5 vol % cobalt napthenate (accelerator), and the mixture

was stirred to ensure a homogeneous mixture.

The resin mixture was then used to fabricate the

mixture of basalt and jute fibers through the compression

molding technique. For all the samples, a total of 12 layers

with four layers in each stage was maintained. For the

alternating stacking sequence, a total of 12 layers with

one layer in each stage was maintained. Hence, a uniform

thickness was obtained with varying stacking sequence.

The detail of the stacking sequence is presented in Table 3 .

The samples were allowed to cure for about 3 to 4 h at

room temperature. A similar procedure was adopted

for the preparation of the basalt-jute fiber-reinforced

polymer composites with a varying stacking order. The

strong hydrogen bonding interaction between the car-

bonyl group of the polyester resin matrix and the hydroxyl

group of the basalt and jute fibers as reinforcing materials

resulted in the matrix and fiber being held very close to

each other, which enhanced the properties of the compos-

ite materials .

3 Mechanical property evaluation

3.1 Tensile strength

The tensile test is generally performed in a universal

testing machine. The dimension of the specimen was

165 × 13 × 3 mm, and a thickness of 3 mm was maintained

for the composite specimen. The tensile test was per-

formed in an AUTO make universal testing machine (UTM)

(capacity 3 Ton) with a crosshead of 1 mm/min, and the

test was done as per ASTM D638 standards.

3.2 Flexural test

The three-point bending test was used to determine the

flexural modulus, flexural strength, and strain at break of

the basalt fiber-reinforced polymer composites. Flexural

tests were conducted on the cured samples (sample size

127 × 13 × 3 mm) using a UTM (Deepak Polyplast Pvt. Ltd.,

SI no.

1 2 3 4 5 6 7 8 9

Stacking sequence B/B/B B/B/J B/J/B B/J/B/J/ … B/J/J J/B/B J/B/J/B/J/ … J/J/J J/J/B

Table 3 Possible stacking sequence.

Ahmedabad, India) with a crosshead speed of 2 mm/min

according to ASTM D790-98; a span length of 50 mm was

maintained.

3.3 Impact strength

An impact test was used to determine the amount of

energy required to break the specimen. An un-notched

Izod Impact test was conducted to study the impact energy

according to ASTM D256 (Deepak Polyplast Pvt. Ltd.). The

un-notched specimens were kept in a cantilevered posi-

tion, and a pendulum was swung around to break the

specimen. The impact energy (Joules) was calculated

using a dial gauge that was fitted to the machine.

All tests were performed with five samples, and the

mean was reported.

4 Results and discussion

4.1 Tensile strength

It was obvious that the pure basalt fiber polymer com-

posite has better properties than the hybrid with natural

fiber. These properties were lower by 21.8 % in composites

with an alternating stacking sequence of basalt and jute

fibers than in composites with only basalt fiber layers;

the former is 16.3 % greater than B/J/J composites with

respect to these properties. Between pure basalt and

pure jute fiber composites, the basalt fiber composite was

53.1 % greater than the jute fiber composite. The alter-

nating arrangement of basalt and jute fiber exhibited an

average tensile strength of 126.26 MPa. The average tensile

strength of the B/B/J combination was found to be 130.17

MPa. Increasing the stacking sequence of the basalt fiber

increased the mechanical properties. The tensile strength

values are plotted in Figure 1 .

During the tensile test of the hybrid composites, a

displacement of the hybrid composites was observed,

with the B/J/J stacking order having a higher displace-

ment of 15.5 mm. The alternate stacking sequence of the




hybrid composites had a displacement of 15.2 mm. From

the displacement data of hybrid composites, it was noted

that adding more layers of jute fiber to the composites

increases the elongations. Figure 2 shows the graph of the

stacking sequences vs. displacement.

The layering pattern of the basalt and jute fibers in

the hybrid composite was reported to affect the tensile

strength and the displacement of the hybrid composites,

and in using a hybrid composite that contains two fibers,

the advantages of one could compensate for the proper-

ties lacking in the other. In the present case, the lack of

tensile strength in the natural (jute) fiber is compensated

by the high tensile strength of the synthetic (basalt) fiber.

This results in the basalt fiber breaking-down failure

when a high load is applied, which transfers a high stress

to the weaker jute fabric. The jute fabric alone cannot

withstand the heavy load, and this leads to the failure

of the fiber, resulting in the failure of the composite. The

typical microscopic examination of the causes of failure is

presented in Figure 3 .

4.2 Flexural strength

The stacking order of B/B/B-reinforced composite was

34.30 % greater than that of the B/B/J sequence. When

compared with pure basalt fiber polymer composites,

those with the B/J/B stacking order were 2.73 % lower. The

alternate sequence of basalt and jute fiber (B/J/B/J/ … ) was

30.99 % greater than the B/J/B combination (Table 4, Figure

4 ). A better mechanical interlocking between the natural

fibers exhibits better properties, and it is poor when com-

bined with the synthetic fiber due to poor adhesion. The

jute fiber at the outer layer surface can have more stress,

and when combined with the basalt fiber, the failure of

the compo sites occurs due to failure and delamination

A

B

Figure 3 (A) and (B) SEM images of tensile tested specimen.

180160140120100

80

Tens

ile s

treng

th (M

Pa)

604020

0

Stacking sequence

B/B/B

B/J/J

B/J/B

B/B/J

J/J/B

J/B/B

B/J/B/J/

B/JJ/J

/J

J/B/J/

B/J/B

Figure 1 Tensile strength of the different stacking sequences of

composites.

1816141210

8

Dis

plac

emen

t at F

MA

X (m

m)

6420

Stacking sequenceB/B

/BB/J/

JB/J/

BB/B

/JJ/J

/BJ/B

/B

B/J/B/J/

B/JJ/J

/J

J/B/J/

B/J/B/J

Figure 2 Displacement of the different stacking sequences of

composites.

of the outer jute layer. Hence, the flexural strength domi-

nates in the J/J/J composite when compared with other

combinations.

Flexural modulus is a measure of resistance to

deformation during bending. The flexural modulus of

basalt-jute fiber-reinforced polymer composites with dif-

ferent stacking sequence was tested, and the results are




450500

400350300250200

Flex

ural

stre

ngth

(MP

a)

150100

500

Stacking sequence

B/B/B

B/J/B

B/J/B/J/

B/JB/J/

JJ/B

/BJ/J

/JJ/J

/B

J/B/J/

B/J/B

B/B/J

Figure 4 Flexural strength of hybrid composites.

Stacking sequence Increased by ( % )

B/B/B > J/J/J 38.67

J/B/J/B/J/ … > B/J/B 9.39

B/J/J < J/B/B 12.48

B/B/J > B/J/B 0.1

Table 5 Percentage variations in flexural modulus.

Flex

ural

mod

ulus

(N/m

m2 )

2000

3000

4000

5000

6000

1000

0

Stacking sequence

B/B/B

B/J/B

B/J/B/J/

B/JB/J/

JJ/B

/BJ/J

/J

J/B/J/

B/J/B

J/J/B

B/B/J

Figure 5 Flexural modulus of hybrid composites.


B/B/B > J/J/J 21.52

J/B/J/B/J/ … > B/J/B 14.04

B/J/J < J/B/B 11.93

B/B/J > B/J/B 2.73

Table 4 Percentage of flexural strength variations with stacking

sequence.

presented in Figure 5 . It was obvious that the B/B/B stack-

ing sequence was greater than the other combination. The

percentage variations in flexural modulus are represented

in Table 5 .

The failure of the composites during the three-point

bending load was mainly observed with the delamination

of the hybrid composites. Delamination causes damage

to the waxy layer present in the surface of the jute fiber

(Figure 6 , white surface). When the outer surface of the

composites is layered with the jute fiber, immediate failure

occurred at the leading surface of the composites. The

flexural properties of hybrid fiber-reinforced plastics are

not only dependent on the hybrid composition but also on

the arrangement of the material layers. Due to lower strain

of the jute fiber, a better modulus exists in the jute fiber

composites and it is not noticed for other combinations

due to poor interfacial bonding between the fibers .

4.3 Impact strength

The stacking order of the alternate combination of basalt-

jute fiber (B/J/B/J/ … )-reinforced composite was 69.68 %

greater than the B/J/J fiber-reinforced composite. The

stacking of the alternate combination of the basalt-jute

hybrid-reinforced composite was 57.37 % greater than




A

B

Figure 6 (A) and (B) SEM images of the flexural-tested specimen.

Impa

ct s

treng

th (J

/cm

2 )

10

15

20

25

30

35

5

0

Stacking sequence

B/B/B

B/J/B

B/J/B/J/

B/J.,

B/J/J

J/B/B

J/J/J

J/B/J/

B/J.,

J/J/B

B/B/J

Figure 7 Impact strength of hybrid composites.

that of the B/B/J fiber-reinforced composite. Similarly,

the J/J/B combination was 35.8 % greater than the B/B/J

stacking order (Figure 7 ). The percentage of variation in

the stacking sequence of polymer composites is presented

in the Table 6 .

The failure of composites was due to the waxy

layer in the jute fiber (Figure 8 ). In some cases, the


B/B/B > J/J/J 6.9

J/B/J/B/J/ … > B/J/B 17.42

B/J/J < J/B/B 72.4

B/B/J < B/J/B 63.1

Table 6 Percentage of variation in impact strength of composite.

A

B

Figure 8 (A) and (B) SEM images of the impact-tested specimen.




delamination of the hybrid composites is due to the lack

of bonding strength between the fiber and the matrix.

In the visualization of the impact-tested area, delami-

nation developed near the outer surface of the compo-

sites when the impact force traveled through the width

of the specimen, and fiber failure and matrix cracking

were the dominant damage. It may be suggested that

the presence of basalt fiber multilayers tends to stop

crack propagation and thus shows that the resistance

to impact loading of basalt-jute fiber-reinforced poly-

ester composites improves with fiber alone. In addition,

alternate layering arrangements offered resistance to

impact load, and it is important to note that the stack-

ing sequence has a great significance on the damage of

hybrid composites.

5 Mechanism of failure The failure of the hybrid composites was analyzed using

SEM. During the testing of the delamination, voids,

failure of fiber, fiber pull-out, and debonding were

observed.

In tensile tests, the failure of composites started with

the jute fiber and propagated to the consecutive layers of

the composite. After the failure of the jute fiber, the basalt

fiber started to fail and elongated to some extent; the

hybrid composites were the last to fail. A typical micro-

graph of the specimen is presented, and the SEM image

of tensile-tested specimens showed that the waxy layer

and the moisture content of the jute fiber is higher than

the basalt fiber. During the flexural test of hybrid com-

posites, the failure started from the bottom layer of the

composites and gradually propagated to the successive

layers of the composites; this was observed through SEM

examinations. The impact strength of the hybrid compo-

sites revealed that the delamination is due to the presence

of jute fiber at the outer layer. Jute fibers can withstand a

higher impact load nearer to the basalt fiber. It can be sug-

gested that the presence of basalt fiber multilayers tends

to stop crack propagation, which is not the case for the

jute fiber layers.

In all the stacking sequences of basalt and jute fiber

hybrid composites, by alternating both fibers, the compos-

ite exhibits properties superior to other stacking orders.

Improper interfacial bonding due to the waxy layer of jute

fiber leads to delamination on application of the load.

The alternating combination, in which one is placed over

another, leads to a relatively increased bonding strength.

Delamination occurred because of improper bonding

between the reinforcement and the matrix, which in turn

was due to the waxy layer of the jute fibers. This is due to

the fact that delamination tends to occur at the interface

of two different layers, such as delamination between jute

fiber-polyester and basalt fiber-polyester. Due to the closer

packing of plain woven fibers, it prevented the crack prop-

agation and the load transfer at the fiber matrix interface

is found to be most effective.

6 Conclusion This comparative study of different hybrid configurations

based on basalt fiber-jute fiber-reinforced laminates con-

firms the slight superiority of basalt fiber-woven lami-

nates over jute fiber.

From the experimentation, the following results

emerged:

– Based on the tensile test, the tensile strength

exhibited by the composite material with stacking

of basalt fiber is significant. When compared with

hybrid composites, the B/B/J stacking order had the

highest tensile strength.

– From the impact test, it is seen that hybrid

composites influence the impact strength. The B/J/B

stacking shows a better impact strength among

hybrids of basalt and jute fibers.

– In the flexural test, the flexural strength and flexural

modulus are highest for the composite material with

the alternate stacking of basalt fiber and jute fiber-

reinforced polyester matrix composites.

Overall analysis shows that the reinforcement of the

basalt fiber composites with jute fiber composites has a

considerable effect on the mechanical properties of the

hybrid composites. The lack of mechanical properties of

the jute fiber was compensated for by the basalt fiber,

and the alternating combination of basalt and jute fiber

hybrid composites shows better mechanical properties. It

is clearly seen that hybridizations are able to slow down

the damage to the composites.

Acknowledgements: We gratefully acknowledge the

financial assistance provided by Department of Science

and Technology (DST), Government of India, vide sanc-

tion SR/S3/ME/0038/2007, for this work. The authors also

thank the Centre for Composite Material, Department of

Mechanical Engineering, Kalasalingam University for

their extended support to carry out the work.

Received June 25, 2012; accepted September 27, 2012; previously

published online November 12, 2012




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influence of stacking sequence on mechanical properties of basalt-jute fiber-reinforced polymer...

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