HARDNESS, CHEMICAL RESISTANCE AND VOID CONTENT OF REINFORCED COW DUNG- GLASS FIBER...

HARDNESS, CHEMICAL RESISTANCE AND VOID CONTENT OF REINFORCED COW DUNG-GLASS FIBER POLYESTER HYBRID COMPOSITES

T RANJETH KUMAR REDDY

Research Scholar, Department of Physics, Jntua ,Anantapur-51500, Andhrapradesh, India

[email protected]

Abstract

In this paper, Hardness, Chemical Resistance and Void Content of hybrid composites with and without alkali treatments were studied. Variation of the above mentioned mechanical properties and chemical resistance were studied with different Cow dung percentage of weight at 5%, 7%, and 10% at constant glass fiber reinforced into the polyester matrix. It is observed that mechanical properties were optimally improved at 7% when compared with 5% and 10 % weight of Fiber. Chemical resistance was also significantly improved for all chemicals except sodium carbonates and toluene. It was observed that the Void content% is reduced in treated composite when compare with the untreated composite. The effect of alkali treatment on the bonding between cow dung/glass composites was also studied. Scanning electron microscope (SEM) were also conducted on the cross sections of fractured surfaces in order to rate the performance hybrid composites were also identified.

Keywords: Cow dung, Glass fiber, Hybrid composites, mechanical properties, Chemical resistance, void content

I. INTRODUCTION

In every automobile and aircraft parts manufacturing industries, the glass with natural fibers are used because of their adaptability to different situations and the relative ease of combinations with other materials to serve specific purpose and exhibit desired properties. Unprecedented plastics usages are inevitable in these days as it is versatile material that lends itself to many uses. The turnaround in favor plastic happened not just because of color and durability for household products but also because plastics as an accessory became fashionable and trend setters. Today Polymer composites find their way into several new applications from golf clubs and tennis rackets to Jet Ski, aircraft, missile, spacecraft and marine applications. Not only with that, the other uses include spaceships, transportation, chemical equipment and machinery construction, electrical and electronics equipment, fishing rods and storage tanks. A composite is made by combining two or more dissimilar materials in such a way that the resulting material is capable with some superior and improved properties. Owing to these superior properties, polymer composites find various applications in our daily life. Composites are light weight, high strength to weight ratio and stiffness properties have come a long way in

replacing the conventional materials such as metals and wood. Composites materials are attractive because they combine material properties not found in nature. Such materials often results in light weight structures having high stiffness and tailored properties for specific applications, thereby saving weight and reducing energy needs. In fiber reinforced composites, the fibers serves as reinforcement by giving strength stiffness to the structure while the plastic matrix serves as the adhesive to hold the fibers in place so that suitable structural component can be made. Fiber reinforced polymer composites have potential application in structural and non-structural areas as they have interesting properties such as high specific stiffness and strength, good fatigue performance and damage tolerance, corrosion resistance, low thermal expansion, non-magnetic properties and low energy consumption during fabrication. There are two types of fibers, that are used as reinforcements; natural and synthetic fibers. A lot of work has been done on the composites based on these fibers [1–4]. In recent years, there is growing interest in the use of natural fibers as reinforcing components for thermo plastics and thermosets. The growing interest in natural fibers is mainly due to their economical production with few requirements for equipment and low specific weight, which results in a higher specific strength and stiffness

National Journal on Chembiosis, Vol. 4 No. 2 Oct 2013 14

when compared to synthetic fibers composites. Also, they offer safer handling and working conditions compared to synthetic fibers. Natural fibers from renewable natural resources offer the potential to act as a biodegradable reinforcing materials alternative for the use of synthetic fibers. These fibers offer several advantages including high specific strength and modulus, low cost, low density, renewable nature, biodegradability, absence of associated health hazards, easy fiber surface modification, wide availability and relative non abrasiveness. The physical and mechanical properties of natural fibers are mainly depended on their physical composition such as structure of fibers, cellulose content, angle of fibrils, and cross section. Jute has good physical and mechanical properties compare to other natural fibers. The physical and mechanical properties of jute fiber and oil palm EFB fiber identified [5,6].Composites materials comprising two or more fibers in a single matrix, which are called hybrid composites have been attracting the attention of researchers [7–9]. Hybridization with more than one fiber type in the same matrix provides another dimension to the versality of fiber reinforced composite materials. Properties of the hybrid composite may not follow from a direct consideration of the independent properties of the individual components. [10,11] studied the tensile, flexural, and chemical resistance properties of waste silk fabric-reinforced epoxy laminates and also studied the impact, compression, density, void content, and weight reduction Studies on waste silk fabric/epoxy composites.[12,13] studied the chemical resistance of kapok/glass and kapok/sisal fabrics reinforced unsaturated polyester hybrid composites and they also studied the compressive, chemical resistance, and thermal properties on kapok/sisal fabrics polyester composites. Various researcher studied chemical resistance, physical and mechanical properties of natural fiber reinforced polymer composites [14–20]. Several authors made large quantity of work on this Hybrid composites but the main intend and scope of the author is to build a composite system which has a high performance, biodegradable and cost-effective. In this study, the authors developed Cow dung/glass hybrid composites as a function of fiber Weight. Six different samples were prepared in which three treated hybrid composites samples and three untreated hybrid samples as a function of fiber weight of 5%, 7%, and 10% respectively. Deviation of hardness, chemical resistance and Void Content was studied at different fiber weight. The effect of alkali treatment on the

bonding between cow dung/glass composites was also studied. Scanning electron microscope (SEM) were also conducted on the cross sections of fractured surfaces in order to rate the performance hybrid composites were also identified.

II. METHODOLOGY

2.1Materials

Cow dung obtained from neighborhood sources and some of these fibers were soaked in 5% NaOH solution for 30 min. To remove any slippery material and hemi cellulose, cleaned thoroughly in purified water and dried up under the sun for one day. The glass chopped strand mat was used in manufacture the hybrid composite in different fractions. The unsaturated polyester resin obtained from Sree Composites world. Secunderabad, A.P, India, Methyl Ethyl Ketone Peroxide as accelerator and Cobalt Naphthenate as catalyst, which are obtained from M/S Bakelite Hylam Hyderabad, A.P, India, were used. Acetic acid, nitric acid, hydrochloric acid, ammonium hydroxide, aqueous sodium carbonate, aqueous sodium hydroxide, carbon tetrachloride, benzene, toluene, and distilled water were supplied by Aldrich Company.

2.2. Preparation of the Composite and test specimen

In this present work the composites were prepared by hand lay-up technique. The matrix of unsaturated polyester and monomer of styrene are mixed in the ratio of 100:25 parts by weight respectively. Later cow dung is mixed systematically and then the accelerator of methyl ethyl ketone peroxide 1% by weight and catalyst of cobalt naphthenate of 1% by weight were added to the combination and mixed carefully. The releasing agent of silicon is sprayed to glass mould and the matrix mixture is poured in to the mould. The fiber is added to matrix combination, which was poured in the glass mould. The excess resign was removed from the mould and glass plate was placed on the top the casting were allowed to cure for 24hrs at room temperature and then casting is placed at a temperature of 70oC for 3 hrs. The composite were released from mould and are cut to prepare test specimens.

After curing, the plate was detached from the mould box with simple tapering and it was cut into samples for

Ranjeth et. al. : Hardness, Chemical Resistance and void content... 15

Hardness Test and Chemical Resistance Test withdimensions of ASTM D 785-08 and ASTM E 18-11 (10×10×6mm3) and ASTM D 543-87(5x5x3mm3). For consideration sake the specimen for matrix material were also prepared in similar lines. Scanning electron microscope analysis the cryogenically cooled and fractured specimen surfaces were gold coated and the fracture surface was observed using scanning electron microscope.

2.3 Rockwell Hardness Test

The hardness of treated and untreated samples reinforced with Cow dung/glass Polyester-based hybrid composites was measured using Rockwell hardness testing machine supplied by M/s. PSI sales (P) Ltd., New Delhi. In each case, five samples were tested and the average value tabulated. Test specimens were made according to the ASTM D 785-08 and ASTM E 18-11 (10×10×6mm3) [21, 22]. The diameter of the ball indenter used was 0.25 inches and the maximum load applied was 60 kg as per the standard L-scale of the tester. The testing was carried out at room temperature for all the samples. All the readings were taken 10 s after the indenter made firm contact with the specimen. All the sample surfaces were rubbed with smooth emery paper, which facilitates accurate reading. Cow dung-glass fibers impregnated in a unidirectional manner with different Cow dung fiber weight% are given in Table.1

2.4. Chemical Resistance Test

To study the chemical resistance of the composites, the test method ASTM D 543-87 was employed. Three acids, three alkalis and four solvents were used for this purpose. Acetic acid, nitric acid, hydrochloric acid, ammonium hydroxide, aqueous sodium carbonate, aqueous sodium hydroxide, carbon tetrachloride, benzene, toluene, and distilled water were used after purification. In each case, the samples (5x5x3) mm3 were pre-weighed in a precision electrical balance and dipped in the respective chemical reagents for 24 hrs. They were then removed and immediately washed in distilled water and dried by pressing them on both sides with a filter paper at room temperature. The treated samples were then reweighed and the percentage loss/gain was determined using this equation.

Weight loss (%) =

2.5. Void Content:

For determination of voids in composites, ASTM D 2734-94 method was used. The void content was determined from the theoretical and experimental density of the composites through below equation

Void Content = (ρtheoritical – ρexperimental )/ ρtheoritical

2.6. Scanning Electron Microscopy Analysis

A Joel JSM-6400 Japan scanning electron microscope (SEM) at 20 kV accelerating voltage equipped with energy dispersive spectroscopy (EDS) to identify the fractured surfaces were gold coated with a thin film to increase the conductance for SEM for analysis.

III. RESULTS AND DISCUSSION

3.1. Rockwell Hardness Test

From Table 1, it was observed that 7% fiber weight composites had a higher hardness than 5% and 10% fiber weight composites. It was observed that the treated composites posses’ higher hardness than untreated as alkali treatment improves the adhesive characteristics of cow dung fiber surface by removing hemicellulose and lignin. This surface offers an excellent fiber matrix interface adhesion and results in the increase in the mechanical properties. The effect of fiber Weight on hardness measurements of Cow dung/glass Polyester hybrid composites is shown in Figure 1

3.2. Chemical Resistance Test

Chemical resistance tests are used to find the ability of a composite to withstand exposure to acids, alkalis, solvents and other chemicals. The chemical resistance tests of these hybrid composites were performed in order to find out whether these composites can be used for making articles that are resistant to chemicals. The weight loss/gain for the Treated and Untreated samples Of Cow dung/glass fibers reinforced hybrid composites with different chemicals were shown in Table 2.From this table it was clearly evident that weight gain is observed for almost all the chemical reagents except sodium carbonate and toluene

16 National Journal on Chembiosis, Vol. 4 No. 2 Oct 2013

. Table 1: Hardness of untreated and treated Polyester-based Cow dung/glass fiber hybrid composites with different fiber weight.

S. no. Cow dung fiber Weight%

Untreated Composite Treated Composite

1 5 112 115

2 7 114 118

3 10 106 110

5% 7% 10%

106

108

110

112

114

116

118

Har

dnes

s

Cowdung fiber wt%

Untreated Hybrid Composite Treated Hybrid Composite

Figure 1: Hardness of untreated and treated Polyester-based Cow dung/glass fiber hybrid composites with different fiber weight

. The weight increase of the composites was larger for aqueous solutions, and this was to be expected as a result of the hydrophilicity of the fiber. It is also observed from the table that treated composites also have weight loss in sodium carbonate. The reason is attack of the carbonated hydrocarbons on the cross-linked polyester hybrid system. The positive values indicate that the composite materials were swollen with gel formation rather than dissolving in chemical reagents. It was further observed that composites were also resistant to water. This study epitomes clearly that the cow dung/glass hybrid composites are substantially resistant to almost all chemicals except sodium carbonate and toluene. Therefore, observations suggest that these hybrid composites can be used in aerospace, automobile, and marine applications for making water and chemical storage tanks.

Table 2: Chemical resistance of Polyester based treated and

untreated Cow dung/glass hybrid fiber composites.

Name of the chemical

Weight in gain (+)/loss (-) (%)

Treated Untreated Hydrochloric

acid +1.273 +1.985

Acetic acid +0.441 +0.549

Nitric acid +2.178 +2.479

Sodium hydroxide

+0.768 +0.914

Sodium carbonate

-0.445 -0.657

Ammonium hydroxide

+0.460 +0.621

Benzene +12.426 +13.235

Toluene - 05.810 - 07.879

Carbon tetrachloride

+2.545 +3.858

Distilled water +1.623 +1.948

3.3. Void content

Most of the composites suffer to exhibit their exotic properties like mechanical and physical properties due to the presence of void content in the composites it reduces the mechanical and physical properties of the composites. At the time of manufacturing due to the impregnation of fiber into the matrix or during manufacturing of fiber reinforced composites, the trapped air or other volatiles exist in the composites. The most common cause of voids is the incapability of the matrix to displace all the air which is entrained within the woven or chopped fibers as it passes through


the matrix impregnation. The void content (%) of Untreated and Treated composite samples with different fiber weight% is shown in Table 3. It is observed that the void content% in both Untreated and Treated samples is decreased with increasing cow dung fiber percentage. The effect of alkali treatment clearly indicates that the void content % is significantly higher at Untreated Composite when compare with the Treated Composite. Due to eliminating the hemicellulose content of the Cow dung fiber in treated composites it greatly reduces the void content in it. This helps for to show the significant improvement in mechanical and physical properties.

Table 3: Void Content% of Untreated and Treated Composites with Cow dung fiber weight %

S. no.

Cow dung fiber

Weight%

Void Content%

Untreated

Treated

1 5

4.25

1.27

2 7 3.42 1.12

3 10 2.36 0.82

3.4. Scanning electron microscope Analysis

The scanning electron macrographs of fiber surfaces of the untreated and treated fibers were shown in the Figure 2 & Figure 3 respectively. Significant changes were observed in each case. For example, the content of white components belonging to the hemicellulose in the untreated fiber (figure 2) decreased on the alkali treatment (figure 3). This indicates the elimination of some surfaces held hemicellulose by the NaOH solution. It can also observed from the graphs after treatment surface were become rough that may be sound great in building strong interface. It can also observe that the white layer (corresponding to hemicellulose) is decreased considerably upon alkali treatment. This is as expected since the hemicellulose is soluble in aq NaOH solution. A rough and cellulose removed surface can be seen in the later figure, where as white cellulose flakes can be seen on the former microgram was the clear indication of the decrease in composites behavior.

Figure 2: SEM micrograph of the untreated cow dung fiber

Figure 3: SEM micrograph of the treated cow dung fiber

IV. CONCLUSIONS

It is observed with the effect of alkali treatment, Hardness of the Untreated and Treated Composites is very high at 7% weight of the cow dung fiber and later with increasing of the cow dung fiber weight% Hardness is decreased. Ii is clearly evident that weight gain is observed for almost all the chemical reagents except sodium carbonate and toluene. The weight increase of the composites was larger for aqueous solutions, and this was to be expected as a result of the hydrophilicity of the fiber. The Void content % is decreased with increasing of the fiber weight% in both untreated and


REFERENCES

[1] Guduri BR, Varada Rajulu A, Luyt. Chemical resistance, void contents and morphological properties of hildegardia fabric/poly carbonate-toughened epoxy composites. J Appl Polym Sci 2007;106:3945–51

[2] Padma Priya S, Rai SK, Varada Rajulu A. Impact, compression, density, void content, and weight reduction studies on waste silk fabric/epoxy composites. J Reinf Plast Compos 2005;24:1605–10.

[3] Varada rajulu A, Rama Devi R. Tensile properties of ridge gourd/phenolic composites and glass/ridge gourd/phenolic hybrid composites. J Reinf Plast Compos 2007;26:629–38.

[4] John K, Venkata Naidu S. Sisal fiber/glass fiber hybrid composites: the impact and compressive properties. J Reinf Plast Compos 2004;23:1253–8.

[5] Khalil HPS Abdul, Hanida S, Kang CW, Nik Fuaad NK. Agro-hybrid composite: the effects on mechanical and physical properties of oil palm fiber (EFB)/glass hybrid reinforced polyester composites. J Reinf Plast Compos 2007;26(2): 203–17.

[6] Bledzki AK, Gassan J. Composite reinforced with cellulose based fibres. Prog Polym Sci 1999;24:221–74.

[7] Noorunnisa Khanam P, Mohan Reddy M, Raghu K, John K, Venkata Naidu S. Tensile, flexural and compression properties of sisal/silk hybrid composites. J Reinf Plast Compos 2007;26:1065–70.

[8] Idicula Maries, Malhotra SK, Joseph Kuruvilla, Thomas Sabu. Dynamic mechanical analysis of randomly oriented intimately mixed short banana/ sisal hybrid fibre

reinforced polyester composites. Compos Sci Technol 2005;65:1077–87.

[9] Abu Bakar A, Hariharan, Khalil HPS Abdul. Lignocellulose based hybrid bi-layer laminate composite: part 1. Studies on tensile and impact behaviour of oil palm fibre/glass fibre reinforced epoxy resin. J Compos Mater 2005; 39(8): 663–84.

[10] Padma Priya S, Ramakrishna HV, Rai SK. Tensile, flexural, and chemical resistance properties of waste silk fabric-reinforced epoxy laminates. J Reinf Plast Compos 2005;24:643–8.

[11] Khalil HPS Abdul, Hanida S, Kang SCW, Nik Fuaad NA. Agro-hybrid composite: the effects on mechanical and physical properties of oil palm fiber (EFB)/glass hybrid reinforced polyester composites. J Reinf Plast Compos 2007;26:203–18.

[12] Venkata Reddy G, Noorunnisa Khanam P, Shoba Rani T, Chowdoji Rao K, Venkata Naidu S. Chemical resistance studies of kapok/glass and kapok/sisal fabrics reinforced unsaturated polyester hybrid composites. Bull Pure Appl Sci 2007;26:17–24.

[13] Venkata Reddy G, Venkata Naidu S, Shobha Rani T, Subha MCS. Compressive, chemical resistance and thermal studies on kapok/sisal fabrics polyester composites. J Reinf Plast Compos 2009; 28:1485–94.

[14] Ramakrishna HV, Padma Priya S, Rai SK, Varada Rajulu A. Tensile, flexural properties of unsaturated polyester/granite powder and unsaturated polyester/fly ash composites. J Reinf Plast Compos 2005;24:1279–87.

[15] Kaushik Anupama, Singh Paramjit, Kaushik Jyoti. The mechanical properties and chemical resistance of short glass-fibre reinforced epoxy composites. Int J Polym Mater 2006;55:425–40.

[16] Singha AS, Vijay Kumar Thakur. Chemical resistance, mechanical and physical properties of biofibers-based polymer composites. Polym Plast Technol 2009;48:736–44.

[17] Sreenivasulu S, Vijayakumar Reddy K, Varada Rajulu A, Ramachandra Reddy. Chemical resistance and tensile properties of short bamboo fiber reinforced epoxy/polycarbonate composites. Bull Pure Appl Sci 2006;25C:137–42.

[18] John K, Venkata Naidu S. Chemical resistance of sisal/glass reinforced unsaturated polyester hybrid composites. J Reinf Plast Compos 2007;26:373–6.

[19] Raghu K, Noorunnisa Khanam P, Venkata Naidu S. Chemical resistance studies of silk/sisal fiber-reinforced unsaturated polyester-based hybrid composites. J Reinf Plast Compos 2010;29(3):343–5.


and treated composites. The effect of alkali treatment clearly indicates, the void content% is higher at untreated composites when compare with the treated composites. Because due eliminating of the hemicel-lulose content of the fiber with the alkali treatment. From the observationof the SEM micrograph of the fractured surface the both untreated and treated composites, the hemicellulose content is removed from the fiber in treated composite when compare with the untreated composite.

V. ACKNOWLEDGEMENTS

Authors would like to thank full to Department of Polymer Science and Technology for providing facil-ities and characterizations of samples.

[20] Karina M, Onggo H, Dawan AH, Abdullah, Sypurwadi A. Effect of oil palm empty fruit bunch fibre on the physical and mechanical properties of fibre glass reinforced polyester resin. J Biol Sci 2008;8:101–6.

[21] ASTM-D785.Standard test method for Rockwell hardness plastics and electrical insulating materials. American society for testing and materials; 2008.

[22] ASTM-E18. Standard test method for Rockwell Hardness of metallic materials. American society for testing and materials; 2011


162

Effect on Compressive and Flexural Properties of Cow Dung/Glass Fiber

Reinforced Polyester Hybrid Composites

A.T. Ranjeth Kumar Reddy*1, B. T. Subba Rao

2, C.R. Padma Suvarna

3

1Department of Physics, SRIT Engineering College, Anantapuramu-515701, Andhra Pradesh, India.

2Department of Physics, Sri Krishnadevaraya University, Anantapuramu-515055, Andhra Pradesh, India.

3Department of Physics, JNTU Engineering College, Anantapuramu, Andhra Pradesh, India.

Received 18th

January 2014; Revised 06th

March 2014; Accepted 12th

March 2014

ABSTRACT

In this paper the Effect of Compressive and flexural properties of cow dung/glass fiber reinforced polyester

hybrid composites were studied. In order to make pollution freely is very important to prepare eco-friendly

composites. Two different hybrid composites such as treated and untreated cow dung fibers were fabricated and

effect of alkali treatment of the cow dung fibers on these properties were also studied. It was observed that

Compressive and flexural properties of the hybrid composites increase with increase of cow dung percentage of

weight. These properties found to be higher when alkali treated cow dung fibers were used in the hybrid

composites. The elimination of amorphous hemi-cellulose with alkali treatment leading to higher crystalline of

the cow dung fibers with alkali treatment might responsible for these observations. The effect of alkali treatment

on the bonding between glass / cow dung composites was also studied. Scanning electron microscope (SEM)

were also conducted on the cross sections of fractured surfaces in order to rate the performance hybrid

composites were also identified.

Keywords: cow dung, Glass fiber, Hybrid composites, Compressive, flexural strength

1. INTRODUCTION Natural fibers exhibit many advantageous

properties as reinforcement for composites. They

are low-density materials, yielding relatively light

weight composite with high specific properties.

Natural fibers also offer significant cost advantages

and benefits associated with processing, as

compared to synthetic fibers such as glass, nylon,

carbon, etc. However, mechanical properties of

natural fiber composites are much lower than those

of synthetic fiber composites. Another

disadvantage of natural fiber composites which

makes them less attractive is the poor resistance to

moisture absorption. Hence use of natural fiber

alone in polymer matrix is inadequate in

satisfactorily tackling all the technical needs of a

fiber reinforced composite. In an effort to develop a

superior, but economical composite, a natural fiber

can be combined with a synthetic fiber in the same

matrix material so as to take the best advantage of

the properties of both the fibers. This result in a

hybrid composite evaluated the enhancement in the

properties of coir-polyester composites by

incorporating glass as intimate mix with coir.

Mohan and Kishore reported that jute provided a

reasonable core material in jute-glass hybrid

laminates. They evaluated flexural properties and

compressive properties of the jute-glass reinforced

epoxy laminates fabricated by filament winding

technique using flat mandrel. Four different hybrid

combinations were studied with different glass

fiber volume fractionsand the results were

compared with jute reinforced plastic. They found

substantial increase in flexural and compressive

properties with hybridization. The work of fracture

determined by impact testing on sisal-glass hybrid

composites with two arrangements, one with sisal

shell and glass core and the other with glass shell

and sisal core. They showed that the sisal shell

laminate had the higher work of fracture compared

with glass shell hybrid laminates of equivalent

volume fraction of sisal and glass fibers. Studied

the effect of glass fiber addition on tensile and

flexural strength and izode impact strength of pine

apple leaf fiber (PALF) and sisal fiber reinforced

polyester composites. The unsaturated polyester

based sisal glass composites were studied with 5%

and 8% volume fraction and found a considerable

enhancement in impact, compression, flexural and

tensile properties [1-15].

Mathur synthesized with unsaturated

polyester/epoxy resin the sisal, jute and coir fiber

reinforced composites [16]. Some authors were

discussed on extraction and process the newly

identified elephant grass fiber, vakka fibers by

manual and chemical methods. The result shows

that the percentage of moisture absorption was

higher in vakka fiber than the date and bamboo

I

Available online at

www.ijacskros.com

Indian

Journal of Advances in Chemical Science

Indian Journal of Advances in Chemical Science 2 (2) (2014) 162-166

*Corresponding Author:

Email: [email protected]

Phone: +91 8978975961

163

fiber [17-18]. Obi Reddy et al. prepared the

composites by using the leaf sheath of the coconut

tree and studied its significance with and without

chemical treatment process [19]. The mechanical

properties of the composites were strongly depends

on the fiber volume fraction. The strength of the

banana fiber reinforced composites with the help of

soy protein resin [20]. By using Random

orientation technique prepared natural fiber

reinforced composites. The significance of the

natural fiber composites by making it as a housing

panel [21]. The different interior and exterior

components of the automobiles can be replaced

with the help of natural fiber reinforced composites

[22]. Some other observed change in mechanical

properties of kenaf natural fibers [23]. The

structural stability and adhesion properties

observed in the reinforced composite were

improved by adopting the various chemical

treatment processes [24]. The tensile strength of the

various banana plant fibers and compared the

results with and without chemical treatment

processes [25].

Kline’s study [27] reported an annual growth rate

for natural fiber composites about 60% over the

years 2000-2005. The major part of this growth

was observed in building applications [26], where

the wood fiber composites present a wide

applicability. The automotive industry is also

including some components in natural fibers

reinforced thermoplastics as a way to serve the

environment along with weight and cost savings.

Applications of natural fibers in automotive

applications have been limited to interior

components and truck cabins [26,28] to replace the

components previously made with glass fiber

composites [29,30]. The hemp fibers were the

world’s largest agricultural crop in the early 19th

century, but the interest in this material has

declined with advances in the field of the synthetic

fibers. Actually, the interest is returning due to the

global environmental issues. These fibers have a

strong applicability, for example, in the automotive

industry in components like interior door trim

panels, engine shields, gaskets, seat parts, etc.

Bledzki et al. [31] presents the typical chemical

composition and structure of hemp fibers.

According to Van de Velde and Kiekens [32] the

fiber properties are influenced by many factors

such as: cultivation (variety, climate, harvest,

maturity, retting degree), processing

(decortications, disintegration) and fiber

modification (textile and technical processes).

2. EXPERIMENTAL

2.1. Materials

Cow dung obtained from local sources and some of

these fibers were soaked in 5% NaOH solution for

30 min. To remove any fatty material and hemi

cellulose, washed thoroughly in distilled water and

dried under the sun for one day. The glass chopped

stand mat was used in making the hybrid composite

percentage. The unsaturated polyester resin

obtained from Sree Composites World.ltd,

Secunderabad, A.P, India, Methyl Ethyl Ketone

Peroxide as accelerator and Cobalt Naphthenate as

catalyst, which are obtained from M/S Bakelite

Hylam Hyderabad, A.P, India, were used.

2.2. Preparation of the Composite and test

specimen

In this present work the composites were prepared

by hand lay-up technique. The matrix of

unsaturated polyester and monomer of styrene are

mixed in the ratio of 100:25 parts by weight

respectively. Later cow dung in powder form is

mixed thoroughly and then the accelerator of

methyl ethyl ketone peroxide 1% by weight and

catalyst of cobalt naphthenate of 1% by weight

were added to the mixture and mixed thoroughly.

The releasing agent of silicon is sprayed to glass

mould and the matrix mixture is poured in to the

mould. The fiber is added to matrix mixture, which

was poured in the glass mould. The excess resign

was removed from the mould and glass plate was

placed on the top the casting were allowed to cure

for 24hrs at room temperature and then casting is

placed at a temperature of 70oC for 3 hrs. The

composite were released from mould and are cut to

prepare test specimens. The Instron Universal

Testing Machine (UTM) (supplied by Instron

Corporation, Series 9, automated testing machine)

is used. The test specimens for compressive and

flexural tests were cut as per American standard

testing method (ASTM) D256 specifications. Six

samples were tested in each case and average value

is tabulated. For scanning electron microscope

analysis the cryogenically cooled and fractured

specimen surfaces were gold coated and the

fractures surface was observed using scanning

electron microscope.

2.3 Scanning Electron Microscopy Analysis:

A Joel JSM-6400 Japan scanning electron

microscope (SEM) at 20 kV accelerating voltage

equipped with energy dispersive spectroscopy

(EDS) to identify the fractured surfaces were gold

coated with a thin film to increase the conductance

for SEM for analysis.

3. RESULTS AND DISCUSSIONS

3.1 Flexural and Compressive strength test

The flexural strength and compressive strength of

cow dung fiber reinforced with polyester at

constant glass fiber (untreated and treated short

fiber) composites as a function of fiber content is

presented in Fig 1 and 2, respectively. As can be


164

seen in Fig. 1 and Fig.2, the flexural strength and

compressive strength is increased with increased

fiber content, in both untreated and treated fiber it

would be seen there is high strength in treated

composites over compare with untreated

composites. The reason is in alkali treated fiber the

hemicelluloses content is removed from it and this

gives necessary strength. The reason for this may

again be attributed to the increase of a population

of fiber content and improvement seen in their

interfacial bonding. As supported by the SEM

micrograph (see Fig. 3 & 4). It is evident that

flexural strength and compressive strength of the

treated fiber composites was higher than that of the

untreated fiber composites because of that treated

fibers were well bonded with polyester.

Figure 1: flexural strength of Untreated and

Treated Cow dung % weight

Figure 2: Compressive strength of Untreated and

Treated Cow dung % weight.

Fig .1 & Fig.2 shows the variations in the flexural

strength and compressive strength values over%

increase in volume fractions. It is observed that the

flexural strength values are gradually increased up

to 5% Vf. Beyond 5% Vf of fiber in composite, the

flexural strength is suddenly decreased. Then the

increasing trend suddenly changes and the flexural

strength gets drastically reduced when Vf of fiber

in composite is 7%. During the composite

preparation, if the fiber content is more than 5%

Vf, it leads to excess of its fiber and less interact

with matrix. 5% Vf composite have the maximum

flexural strength of 147.68 MPa and 155.75 MPa

for untreated and treated composite. The similar

effect seen in Compressive strength also. It has

significant change of 5% when the fiber content is

varied. The maximum Compressive strength 5% Vf

composite have 149.85 MPa and 152.45 MPa seen

in untreated and treated composite. In this both

flexural and compressive strength there is

maximum strength is obtained due to the adding a

constant glass fiber content, it is shown from Table

1 and Table 2.

3.2. Morphology Test on Cross Sections of

Fractured Surfaces

To probe the bonding between the reinforcement

and matrix, the scanning electron micrograms of

fractured surfaces of glass/cow dung reinforced

polyester hybrid composites were recorded. These

micrograms were recorded at different

magnifications and regions. The analysis of the

micrograms of the composites prepared under

different conditions is presented in the following

paragraphs.

3.3.1 Untreated cow dung fiber

SEM micrograph analysis of fractured specimen

Fig. 3 shows that the SEM micrograph of flexural

fractured 5% Vf specimen. Due to the flexural load,

the interphase delamination is found at the cross

section of the composite. Due to the uniform

compressive force applied during the

manufacturing of the composite specimen, presence

of voids in the specimen is found to be very

minimal. Fiber pull-out is very much evident in the

micrograph, as the bonding between the fiber and

the matrix is very weak. Due to the fiber pull-out at

the interphase, holes are created because of the

poor interfacial wetting. More pull-out is observed

in the compression region.

Figure 3: SEM micrograph of fractured surface of

untreated cow dung polyester composite

3.3.2. Treated cow dung fiber

The micrograms of alkali treated cow dung fiber

composites are presented in Fig 4. From these

micrograms it is clearly evident that the surface of

0% 2% 3% 5% 7% 10%

115

120

125

130

135

140

145

150

155

160

flexu

ral s

treng

th (M

Pa)

cowdung%weight

treated

untreated

0% 2% 3% 5% 7% 10%

120

125

130

135

140

145

150

155

Com

pres

sive

stre

ngth

(MP

a)

cowdung%weight

treated

untreated


165

Table 1: flexural strength of Untreated and Treated Cow dung % weight.

SNo composite Flexural strength(MPa) Cow dung % by weight of resin

0% 2% 3% 5% 7% 10%

1 Untreated 120.25 124.58 133 147.68 142.44 123.45

2 Treated 120.25 132.58 141.56 155.75 149.45 136.45

Table 2: Compressive strength of Untreated and Treated Cow dung % weight.

Figure 4: SEM micrograph of fractured surface of

alkali treated cow dung polyester composite.

the fibers becomes rough on alkali treatment. The

elimination of hemi-cellulose from the surface of

the cow dung fiber may be responsible for the

roughening of the surface. Here, however the

bonding is improved, fiber pullout is reduced. Thus

the alkali treatment improved the bonding.

4. CONCLUSIONS

In this present study it shows the clear evidence

that cow dung is an alternative material can use

instead of conventional materials because of good

mechanical properties and available flexibly. The

following conclusions are made based on the

experimental study

1. Flexural and Compressive strengths are higher

at 5% Vf of cow dung at constant glass fiber

this supports to enhance the other properties

of materials.

2. Beyond the 5% Vf it is seen gradual decrease

in flexural and compressive strength in both

treated and untreated composites.

3. When observed SEM Micrograph of fractured

specimen of untreated composite a week

interfacial bonding between fiber and matrix

and also presence voids in it.

4. Due alkali treatment the hemi cellulose

content is removed from the Cow dung and

gives necessary strength to the composite

material.

5. This is a evident of wile manufacturing of

composite the volume fraction of material was

plays a vital role. Cow dung is available

flexibly in local resources and have good

application in all areas.

6.

5. REFERENCES

[1]. M.A Dweib, B Hu, A.O’Donnell, H.W

Shenton, R.P Wool(2004) All natural

composite sandwich beams for structural

applications. Compos. Struct 63, 147-157.

[2]. K. John, S.Venkata Naidu(2004a) Sisal

fiber/glass fiber hybrid composites: impact

and compressive properties. J. Reinf. Plast.

Compos 23 (12), 1253-1258.

[3]. K.John, S.Venkata Naidu (2004b) Effect of

fiber content and fiber treatment of flexural

properties of sisal fiber/glass fiber hybrid

composites. J. Reinf. Plast. Compos 23

(15), 1601–1605.

[4]. K.John, S.Venkata Naidu (2004c) Tensile

properties of unsaturated polyester based

sisal fiber-glass fiber hybrid composites. J.

Reinf. Plast. Compos 23 (17), 1815-1819.

[5]. Kishore, R. Mohan (1983) Compressive

strength of jute-glass hybrid fiber

composites. J. Mater. Sci. Lett 2, 99-102.

[6]. Kishore, Rengarajan Mohan (1985) Jute-

glass sandwich composites. J. Reinf. Plast.

Compos 4, 186–194.

[7]. Lackey, Ellen, James, G.V. Inamdar, Kapil,

Hancock, Brittany, (2004). Composites

2004 Convention and Trade Show American

Composites Manufacturers Association.

Tampa, Florida, USA, 1-9.

[8]. P.K. Mallick. Fiber Reinforced Composites-

Materials (1993) Manufacturing and

Design, Second Edition. Marcel Dekker,

Inc., New York, 243-244.

[9]. F.L Mathews, R.D Rawlings, Composite

Materials (1999) Engineering and Science,

Second Edition. Woodhead Publishing Ltd.

and CRC Press, Boca Raton, p. 470.

[10]. S.Mishra, A.K. Mohanty, L. T .Drzal, M.

Misra, S. Parija , S.K. Nayak, S.S. Tripathy

(2003) Studies on mechanical performance

S.No composite Compressive strength(MPa) Cow dung % by weight of resin

0% 2% 3% 5% 7% 10%

1 Untreated 124.5 132 142.56 149.85 135.46 125.45

2 Treated 124.5 138.89 148.48 152.45 146.48 135.45


166

of biofiber/glass reinforced polyester hybrid

composites. Compos. Sci. Technol, 63,

1377-1385.

[11]. T. Munikenche Gowda, A.C.B Naidu,

Chhaya, Rajput (1999) Some mechanical

properties of untreated jute fabric-reinforced

polyester composites. Compos. Pt. A; 30,

277-284.

[12]. C. Pavithran, P.C. Mukherjee, M Brahma

Kumar (1991) Coir-glass intermingled fiber

hybrid composites. J. Reinf. Plast. Compos.

10, 91-101.

[13]. C. Pavithran, P.S. Mukherjee, M.

Brahkumar, A.D. Damodaran (1991) Impact

properties of sisal-glass hybrid laminates. J.

Mater. Sci. 26, 452-459.

[14]. A.K.Rana, A.Mandal, S.Bandyopadhyay

(2003) Short jute fiber reinforced

polypropylene composites: effect of

compatibiliser, impact modifiber and fiber

loading. Compos. Sci. Technol. 63,801-806.

[15]. Wambua, Paul, Ivens, Jan, Verpoest, Ignaas

(2003), Natural fibers: can they replace

glass in fiber reinforced plastics. Compos.

Sci. Technol. 63, 1259-1264.

[16]. V.K. Mathur (2006) Composite materials

from local resources. Constr Build

Mater,20, 470477.

[17]. K. MuraliMohanRao, A.V. Ratna Prasad,

M.N.V. Ranga Babu, K. Mohan Rao,

A.V.S.S.K.S Gupta (2007) Tensile

properties of elephant grass fiber reinforced

polyester composite. Mater Sci, 42, 2666-

72.

[18]. K. Murali Mohan Rao, K. Mohan Rao

(2007) Extraction and tensile properties of

natural fibers: Vakka, date and bamboo.

Compos Struct, 77, 288-95.

[19]. K. Obi Reddy, G. Sivamohan Reddy ,C.

Uma Maheswari, A. Varada Rajulu, K.

Madhusudhana Rao (2010). Structural

characterization of coconut tree leaf sheath

fiber reinforcement. J Forest Res, 21(1):53-

8.

[20]. Kumar Rakesh, Choudhary Veena, Mishra

Saroj, Varma Ik (2008) Banana fiber

reinforced biodegradable soy protein

composite. Front Chem China, 3(3), 243–

50.

[21]. Burgueno Rigoberto, J. Quagliata Mario,

Mehta Geeta Misra, K. Mohanty Amar,

Misra Majuri, T. Drzal Lawrence (2005)

Sustainable cellur biocomposites from

natural fibers and unsaturated polyester

resin for housing panel applications. J

Polym Environ, 31,139–49.

[22]. Monteiro Sergio Neves, D. Lopes Felipe

Perisse, O. Nascimento Denise Cristina.

Natural-fiber polymer-matrix composites

(2009) cheaper, tougher, and

environmentally friendly. JOM,61, 17-22.

[23]. Ochi Shinji (2008). Mechanical properties

of kenaf fibers and kenef/PLA composites.

Mech Mater, 40, 446-52.

[24]. Xue Li, G.Tabil Lope, Panigrahi

Satyanarayan. Chemical treatments of

natural fiber for use in natural fiber-

reinforced composites: a review (2007). J

Polym Environ, 15, 25-33.

[25]. A.V. Kiruthika, K. Veluraja (2009)

Experimental studies on the physico-

chemical Properties of banana fiber from

various varieties. Fiber Polym, 10(2),193-9.

[26]. K. Jayaraman (2003) Manufacturing sisal-

polypropylene composites with minimum

fiber degradation. Compos Sci Technol, 63,

367-74.

[27]. Opportunities for natural fibers in plastic

composites (2000). Little Falls, NJ, USA:

Kline & Company, Inc.

[28]. P. Mapleston (1997) Natural-fiber

composites rev-up role in interior panels.

Mod Plast Int : 39-40.

[29]. H. Larbig, H.Scherzer, B.Dahlke, R.

Poltrock (1998) Natural fiber reinforced

foams based on renewable resources for

automotive interior applications. J Cell

Plast, 34, 361–79.

[30]. A.Leao, R.Rowell, N.Tavares (1997)

Applications of natural fibers in automotive

industry in Brazil-thermoforming process.

In: 4th

international conference on frontiers

of polymers and advanced materials

conference proceedings. Cairo, Egypt:

Plenum Press; p. 755-60.

[31]. A.K. Bledzki, S. Reihmane, J. Gassan

(1996) Properties and modification methods

for vegetable fibers for natural fiber

composites. J Appl Polym Sci, 59, 1329-36.

[32]. K.Van de Velde, P. Kiekens(2001)

Thermoplastic pultrusion of natural fiber

reinforced composites. Compos Struc, 54,

355-60.


www.tjprc.org [email protected]

International Journal of Nanotechnology and Application (IJNA) ISSN(P): 2277-4777; ISSN(E): 2278-9391 Vol. 4, Issue 4, Aug 2014, 19-22 © TJPRC Pvt. Ltd.

STUDIES ON COMPOSITIONAL ANALYSIS OF COW DUNG/GLASS FIBER

REINFORCED WITH POLYESTER HYBRID COMPOSITES

T. RANJETH KUMAR REDDY 1 T. SUBBA RAO2, R. PADMA SUVARNA3 & P. SRINIVASULA REDDY 4 1Department of Physics, SRIT Engineering College, Anantapuramu, Andhra Pradesh, India

2,4Department of Physics, Sri Krishnadevaraya University, Anantapuramu, Andhra Pradesh, India 3Department of Physics, JNTU Engineering College, Anantapuramu, Andhra Pradesh, India

ABSTRACT

In this present paper studied compositional analysis of cow dung/Glass fiber reinforced with Polyester Hybrid

composites. It was observed that different compositional analysis in treated and untreated hybrid composites by using

EDAX. This reveals in untreated composite it consisting C, O, Si, Cl, this results get effect on properties of composite.

In treated composite it consisting C, O, Si, Only. This results it shows a spectacular effect on its properties over compare

with untreated hybrid composite.

KEYWORDS: EDAX, Cow Dung, Glass Fiber, Hybrid Composite

INTRODUCTION

Natural fiber reinforced polymer composites have many applications as a class of structural materials because of

their high strength, light weight, less density, and very low cost [1]. By adding the tow or more fibers to the different types

of matrices it will be form hybrid composite. These composites have superior properties while comparing with reinforced

single fiber [2]. The usage of multyfibers will be benefiting in hybrid systems each fiber into a single composite product

[3]. Many of the researches have focused on increase the properties of hybrid composites [4]. It is important the knowledge

on the mechanical properties of materials, which helps for design requirements or formation new hybrid materials.

The properties of vegetable fibers in composites enhances when adding the synthetic fibers [5]. Many factors determine the

final performance of hybrid composites, such as matrix nature, length and shape of the dispersed fiber (isotropic or

anisotropic), fiber–matrix interface and vegetable/synthetic fiber ratio. It was observed that containing low glass fiber

volume content mechanical properties of pineapple leaf (PALF) and sisal fiber reinforced polyester composites [6].

Tensile, flexural and interlaminar shear properties of jute/glass/polyester composites and in addition, that the dynamic

mechanical properties of randomly oriented short banana/ sisal/polyester hybrid composites and concluded that higher

compatibility was obtained hybridizing these fibers, leading to higher stress transfer ability [7-9].Little work explores more

results, many of the researchers attempt to find properties of hybrid composites but no one discussed its elemental analysis.

This gives scope for investigating failures and merits of materials.

METHODOLOGY

Materials

Cow dung obtained from local sources and some of these fibers were soaked in 5% NaOH solution for 30 min.

To remove any fatty material and hemi cellulose, washed thoroughly in distilled water and dried under the sun for one day.

The glass chopped stand mat was used in making the hybrid composite percentage. The unsaturated polyester resin

20 T. Ranjeth Kumar Reddy T. Subba Rao, R. Padma Suvarna, & P. Srinivasula Reddy

Impact Factor (JCC): 1.8003 Index Copernicus Value (ICV): 3.0

obtained from Sree Composites World.ltd, Secunderabad, A.P, India, Methyl Ethyl Ketone Peroxide as accelerator and

Cobalt Naphthenate as catalyst, which are obtained from M/S Bakelite Hylam Hyderabad, A.P, India, were used.

Preparation of the Composite and Test Specimen

In this present work the composites were prepared by hand lay-up technique. The matrix of unsaturated polyester

and monomer of styrene are mixed in the ratio of 100:25 parts by weight respectively. Later cow dung in powder form is

mixed thoroughly and then the accelerator of methyl ethyl ketone peroxide 1% by weight and catalyst of cobalt

naphthenate of 1% by weight were added to the mixture and mixed thoroughly. The releasing agent of silicon is sprayed to

glass mould and the matrix mixture is poured in to the mould. The fiber is added to matrix mixture, which was poured in

the glass mould. The excess resign was removed from the mould and glass plate was placed on the top the casting were

allowed to cure for 24hrs at room temperature and then casting is placed at a temperature of 70oC for 3 hrs. The composite

were released from mould and are cut to prepare test specimens. This specimen was cut into (5×5) cm2 as per ASTM. By

using EDAX these composites compositions should be analyzed in both treated and untreated mode.

RESULTS AND DISCUSSIONS

EDAX Analysis on Untreated and Treated Fiber Hybrid Composites

By using EDAX the composites specimens of its composition were analyzed. The analysis of the composites

prepared under different conditions is presented in the following paragraphs.

Untreated Cow Dung Fiber

EDAX analysis of specimen is shown Figure 1 from this figure it is observed that the presence of compositional

elements in specimen was C, O, Si, Cl, which it gives the information there exist the unwanted elements other than C, O,

Si. It was identified it consist high peaks of other elements. This results get affect the composites properties due poor

interracial bonding in between the fiber and matrix. It is showed in below figure 1

Figure 1: Compositional Analysis in Untreated Cow Dung Fiber Composite

Treated Cow Dung Fiber

EDAX analysis of specimen is shown Figure 2 from this figure it is observed that the presence of compositional

elements in specimen was C, O, Si, It was identified it consist high peaks for the elements of C, O, Si, for remaining the

presence of cow dung fiber it shows saturization with low peaks.

Studies on Compositional Analysis of Cow Dung/Glass Fiber Reinforced with Polyester Hybrid Composites 21

This attempt gives a full information fiber material makes a strong interracial bonding with matrix.

Figure 2: Compositional Analysis in Treated Cow Dung Fiber Composite

ACKNOWLEDGEMENTS

I am thankful to Satyabama University providing resources for compositional analysis.

CONCLUSIONS

In this present study it is clearly showed that different compositional analysis in treated and untreated hybrid

composites by using EDAX. This reveals in untreated composite it consisting C, O, Si, Al, this results get effect on

properties of composite due to poor interfacial bonding with matrix. In treated composite it consisting C, O, Si, Only.

This results it shows a spectacular effect on its properties over compare with untreated hybrid composite due strong

interfacial bonding.

REFERENCES

1. Idicula M, Boudenne A, Umadevi L, Ibos L, Candau Y & Thomas S(2006). Thermophysical properties of natural

fibre reinforced polyester composites. Compos Sci Technol, 66, 2719–25.

2. Shan Y, Liao K. (2002) Environmental fatigue behavior and life prediction of unidirectional glass–carbon/epoxy

hybrid composites. Int J Fatigue, 24,847–59.

3. Peled A, Mobasher B, & Cohen Z. (2009) Mechanical properties of hybrid fabrics in pultruded cement

composites. Cem Concr Compos, 31, 647–57.

4. Paiva C. Z, De Carvalho L.H, Fonseca V.M, Monteiro S.N,& D’Almeida J.R.M (2004). Analysis of the tensile

strength of polyester/hybrid ramie–cotton fabric composites. Polym Test, 2,131–5.

5. Cicala G, Cristaldi G, Recca G, Ziegmann G, El-Sabbagh A, & Dickert M.(2009). Properties and performances of

various hybrid glass/natural fibre composites for curved pipes. Mater Des, 30, 2538–42.

6. Mishra S, Mohanty A.K, Drzal L.T, Misra M, Parija S, & Nayak S.K. (2003), Studies on mechanical performance

of biofibre/glass reinforced polyester hybrid composites. Compos Sci Technol, 63, 1377–85.

7. Ahmed K.S, Vijayarangan S (2008) Tensile, flexural and interlaminar shear properties of woven jute and

jute-glass fabric reinforced polyester composites. J Mater Process Technol, 207,330–5.

8. Idicula M, Neelakantan NR, Oommen Z, Kuruvilla J, & Thomas S (2004). A study of the mechanical properties of

randomly oriented short banana and sisal hybrid fiber reinforced polyester composites. J Appl Polym Sci,

96,1699–709.

22 T. Ranjeth Kumar Reddy T. Subba Rao, R. Padma Suvarna, & P. Srinivasula Reddy


9. Gregorova A, Hrabalova M, Kovalcik R, & Wimmer R (2011) Surface modification of spruce wood flour and

effects on the dynamic fragility of PLA/wood composites. Polym Eng Sci, 51,143–50.

This article appeared in a journal published by Elsevier. The attachedcopy is furnished to the author for internal non-commercial researchand education use, including for instruction at the authors institution

and sharing with colleagues.

Other uses, including reproduction and distribution, or selling orlicensing copies, or posting to personal, institutional or third party

websites are prohibited.

In most cases authors are permitted to post their version of thearticle (e.g. in Word or Tex form) to their personal website orinstitutional repository. Authors requiring further information

regarding Elsevier’s archiving and manuscript policies areencouraged to visit:

http://www.elsevier.com/authorsrights

http://www.elsevier.com/authorsrights

Author's personal copy

Studies on thermal characteristics of cow dung powderfilled glass–polyester hybrid composites

T. Ranjeth Kumar Reddy a,⇑, T. Subba Rao b, R. Padma Suvarna c

a Department of Physics, SRIT Engineering College, Anantapur 515701, Andhra Pradesh, Indiab Department of Physics, Sri Krishnadevaraya University, Anantapur 515055, Andhra Pradesh, Indiac Department of Physics, JNTU Engineering College, Anantapur, Andhra Pradesh, India

a r t i c l e i n f o

Article history:Received 16 March 2013Received in revised form 1 May 2013Accepted 12 August 2013Available online 25 August 2013

Keywords:A. Glass fibersA. HybridB. Thermal propertiesE. Lay-up (manual/automated)E. Thermoplastic resin

a b s t r a c t

In the present work Studies on thermal characteristics of cow dung powder filled glass–polyester hybridcomposites were prepared. Cow dung is a animal based fiber which is also biodegradable and glass fiber isa synthetic fiber. These two natural and synthetic fibers are combined in the same matrix (unsaturatedpolyester) to make cow dung powder filled glass–polyester hybrid composites and the thermal charac-teristics of these hybrid composites was studied. A significant improvement seen in decrease thermalconductivity of cow dung filled glass-polyester hybrid composites has been found. The cow dung powderis added to the resin (unsaturated polyester) in proportions of 3%, 6%, and 9% by weight of resin respec-tively and cow dung/glass fiber hybrid composites were prepared by using this resin to study the effectthermal resistivity character of cow dung on heat capacity of these hybrid composites. It is also observedthat as the cow dung powder quantity decreases thermal conductivity. A good co-relation between sur-face morphology and thermal conductivity of composite is derived from scanning electron microscopy.

� 2013 Elsevier Ltd. All rights reserved.

1. Introduction

Natural fibers such as banana, cotton, coir, sisal and jute have at-tracted the attention of scientists and technologists for application inconsumer goods, low cost housing and other civil structures. It hasbeen found that these natural fiber composites possess better elec-trical resistance, good thermal and acoustic insulating propertiesand higher resistance to fracture. Natural fibers have many advanta-ges compared to synthetic fibers, for example low weight, low den-sity; low cost, acceptable specific properties and they are recyclableand biodegradable. They are also renewable and have relatively highstrength and stiffness and cause no skin irritations. On the otherhand, there are also some disadvantages, for example moisture up-take, quality variations and low thermal stability.

Many investigations have been made on the potential of thenatural fibers as reinforcements for composites and in severalcases the result have shown that the natural fiber compositesown good stiffness but the composites do not reach the same levelof strength as the glass fiber composite. The fibers are basically twotypes viz. natural and synthetic fibers. Cotton, jute and sisal aresome examples for natural fibers and glass, nylon and carbon aresome examples for synthetic fibers. The natural fibers are renew-able [1–7] and cheaper but their mechanical properties are muchlower than the synthetic fibers. The synthetic fibers exhibit good

mechanical properties but they are costlier and nonrenewable.Many researchers developed natural fiber reinforced compositesand studied their mechanical properties. Now a days eco-friendlycomposite had a great importance due to high strength, low costand flexible to usage. Thus most of them prepared hybrid compos-ites with usage of different fibers and also discussed their variousproperties [8–16].

Many of them studied a significant improvement in propertiesof hybrid composites with reinforced with glass fiber in resin con-tent but it is naturally hazard with usage of this glass fiber content.In present work, to take advantage of natural fiber over syntheticfibers is observed, they can be combined in the same matrix to pro-duce composite and their thermal conductivity is studied. Cowdung, also known as cow pat, is the waste product of bovine animalspecies. The resultant fecal matter is rich in minerals.

Cow dung [17] powder (additive) is added to the resin (unsatu-rated polyester) in proportions of 3%, 6%, 9% by weight of resinrespectively and glass–polyester hybrid composites were preparedby using this resin at a constant glass fiber. The effect of cow dungpowder, which is added to the matrix is also studied.

2. Methodology

2.1. Materials

Cow dung obtained from local sources and the chopped strandmat of short glass fiber (2 cm long) were used for present work.

1359-8368/$ - see front matter � 2013 Elsevier Ltd. All rights reserved.http://dx.doi.org/10.1016/j.compositesb.2013.08.059

⇑ Corresponding author. Tel.: +91 8978975961.E-mail address: [email protected] (T. Ranjeth Kumar Reddy).

Composites: Part B 56 (2014) 670–672

Contents lists available at ScienceDirect

Composites: Part B

journal homepage: www.elsevier .com/locate /composi tesb


The unsaturated polyester resin obtained from Sree CompositesWorld, Secunderabad, A.P, India, Methyl Ethyl Ketone Peroxide asaccelerator and Cobalt Naphthenate as catalyst, which are obtainedfrom M/S Bakelite Hylam Hyderabad, A.P, India, were used.

2.2. Composite preparation

In this present work the composites were prepared by hand lay-up technique. The matrix of unsaturated polyester and monomer ofstyrene are mixed in the ratio of 100:25 parts by weight respec-tively. Later cow dung in powder form is mixed thoroughly andthen the accelerator of methyl ethyl ketone peroxide 1% by weight

and catalyst of cobalt naphthenate of 1% by weight were added tothe mixture and mixed thoroughly. The releasing agent of silicon issprayed to glass mould and the matrix mixture is poured into themould. The fiber is added to matrix mixture, which was poured inthe glass mould. The excess resign was removed from the mouldand glass plate was placed on the top the casting were allowedto cure for 24 h at room temperature and then casting is placedat a temperature of 80 �C for 4 h. The composite were releasedfrom mould and are cut to prepare test specimens.

2.3. Scanning electron microscopy analysis

A Joel JSM-6400 Japan scanning electron microscope (SEM) at20 kV accelerating voltage equipped with energy dispersive spec-troscopy (EDS) to identify the fractured surfaces were gold coatedwith a thin film to increase the conductance for SEM for analysis.

3. Experimental procedure

The material of which the thermal conductivity to be deter-mined should be cut into test specimen of 16 mm diameter and3 mm thickness. The thermal conductivity apparatus consists of ahollow cylinder in which heater is arranged. The test specimen isplaced between the brass slabs. The bottom slab is heated up byheater and this heat is transferred to top side through test speci-men material by the mode of conduction.

The heat transfer through sample is given

Q ¼ ðKðT1T2ÞAÞ=d

where K is thermal conductivity cal/s cm �C; T1 is temperature ofbottom slab �C; T2 is temperature of Top slab �C; A is Area of crosssection of sample cm2; d is thickness of sample cm.

ðKðT1 � T2ÞAÞ=d ¼WðdT=dtÞT2:

Thermal conductivity K ¼ ðWðdT=dtÞT2dÞ=ððT1 � T2ÞAÞ Cal S�10cm�1K�1

where w = Water equivalent of brass slab = m � S; m = Weight ofbrass slab = 11.226 gms; S = Specific heat of sample. dT/dt is deter-mined at T2 from the graph plotted between temperature versustime [18].

Fig. 2. SEM micrograph at cross section of hybrid composite.

Table 1Thermal conductivity of cow dung/glass filled polyester composites.

S. No. Fiber Thermal conductivity 10�4 cal/s m �C cow dung powder% by weight of resin

0% 3% 6% 9%

1 Composite 2.56 2.46 2.29 1.82 Glass fiber 2.56 2.64 2.71 2.88

Fig. 1. Themal conductivity with increasing cow dung wt%.

T. Ranjeth Kumar Reddy et al. / Composites: Part B 56 (2014) 670–672 671


4. Results and discussions

4.1. Thermal conductivity

The thermal conductivity of cow dung filled glass-polyester hy-brid composites is presented in Table 1. It is observed that the cowdung powder filled glass–polyester hybrid composite thermal con-ductivity decreases when compare with glass fiber composite. Thedecrease in thermal conductivity of hybrid composite, because ofcow dung powder content it forms a strong interfacial bondingwith glass fiber thus it does not allow the conductivity. The out-come of the cow dung powder composite is observed that asincreasing the quantity of the powder thermal conductivity de-creases. It is shown in Fig. 1.

4.2. Morphology test on cross sections

To probe the bonding between the reinforcement and matrix,the scanning electron micrograms of cross section surfaces ofglass/cow dung reinforced polyester hybrid composites were re-corded. It is shown in Fig. 2 from this, a very less number of voidcontent is observed and the strong interfacial bonding is observedbetween the glass fiber and cow dung fiber. This result gets effecton decreasing in thermal conductivity of hybrid composite.

5. Conclusions

The thermal conductivity of cow dung filled glass-polyester hy-brid composite has been studied as a function of cow dung powdercontent. It is observed that the thermal conductivity of cow dungfilled glass-polyester hybrid component is lower than the glass fi-ber reinforced composite. It shows that how the cow dung powderaffects on thermal conductivity of glass–polyester hybrid compos-ite. Cow dung powder quantity by weight of resin increases thenthe thermal conductivity decreases. The thermal conductivity ofa material depends on the nature of the material, the area of crosssection normal to the direction of heat flow and the temperaturegradient between the hotter part and the colder part of the mate-rial. A good co-relation between surface morphology and thermalconductivity of composite is derived from scanning electronmicroscopy. The thermal resistance of materials is of great interestto electronic engineers because most electrical components gener-ate heat and need to be cooled. Electronic components malfunctionor fail if they overheat, and some parts routinely need measurestaken in the design stage to prevent this.

Acknowledgements

Authors would like to thank for providing Department of Poly-mer Science and Technology for facilities and characterizations forsamples.

References

[1] Idicula M, Boudenne A, Umadevi L, Ibos L, Candau Y, Thomas S. Thermophysical properties of natural fiber reinforced polyester composites. ComposSci Technol 2006;66:2719–25.

[2] Idicula M, Neelakantan NR, Oommen Z, Kuruvilla J, Thomas S. A study of themechanical properties of randomly oriented short banana and sisal hybridfiber reinforced polyester composites. J Appl Polym Sci 2004;96:1699–709.

[3] Cicala G, Cristaldi G, Recca G, Ziegmann G, El-Sabbagh A, Dickert M. Propertiesand performances of various hybrid glass/natural fiber composites for curvedpipes. Mater Des 2009;30:2538–42.

[4] Mishra S, Mohanty AK, Drzal LT, Misra M, Parija S, Nayak SK, et al. Studies onmechanical performance of biofibre/glass reinforced polyester hybridcomposites. Compos Sci Technol 2003;63:1377–85.

[5] Ahmed KS, Vijayarangan S. Tensile, flexural and inter laminar shear propertiesof woven jute and jute-glass fabric reinforced polyester composites. J MaterProcess Technol 2008;207:330–5.

[6] Sayer M, Bektas NB, Callioglu H. Impact behavior of hybrid composite plates. JAppl Polym Sci 2010;118:580–7.

[7] Naik NK, Ramasimha R, Arya H, Prabhu SV, ShamaRao N. Impact response anddamage tolerance characteristics of glass–carbon/epoxy hybrid compositeplates. Composite Part B 2001;32:565–74.

[8] John K, Venkata Naidu S. Chemical resistance studies of sisal/glass fiber hybridcomposites. J Rein Plast Comp 2007;26(4):373–6.

[9] Abdul Khalil HPS, Hanida S, Kang CW, Nikfuaad NA. Agro hybrid composite: theeffects on mechanical and physical properties of oil palm fiber (efb)/glasshybrid reinforced polyester composites. J Rein Plast Comp 2007;26(2):203–18.

[10] Noorunnisha Khanam P, Mohan Reddy M, Raghu K, John K, VenkataNaidu S.Tensile, flexural and compressive properties of sisal/silk hybrid composites. JRein Plast Comp 2007;26(9):1065–9.

[11] Sreenivasulu S, Vijay Kumar Reddy K, Varada Rajulu A, Ramachandra Reddy G.Chemical resistance and tensile properties of polycarbonate toughened epoxy-bamboo fiber composites. Bull Pure Appl Sci 2006;25C(2):137–42.

[12] Algood R, Sharma SC, Syed AA, VaradaRajulu A, Krishana M. Compressionproperties of e-glass/polyurethane composites. J Rein Plast Comp 2006;25(14):1445–7.

[13] Padma Priya S, Rai SK. Impact, compression, density, void content and weightreduction studies on waste silk fabric/epoxy composites. J Rein Plast Comp2005;24(15):1605–10.

[14] Varada Rajulu A, Babu Rao G, Ganga Devi L, Sidda Ramaiah D, Shubhaprada K,Shrikant Bhat K, et al. Mechanical properties of short, natural fiber hildegardiapopulifolia-reinforced styrenated polyester composites. J Rein Plast Comp2005;24(4):423–8.

[15] John K, Venkata Naidu S. Sisal fiber/glass fiber hybrid composites: the impactand compressive properties. J Rein Plast Comp 2004;23(12):1253–8.

[16] Sayer M, Bektas NB, Sayman O. An experimental investigation on the impactbehavior of hybrid composite plates. Compos Struct 2010;92:1256–62.

[17] http://en.wikipedia.org/wiki/Cow_dung.[18] http://v5.books.elsevier.com/bookscat/samples/9780123735881/

9780123735881.pdf.

672 T. Ranjeth Kumar Reddy et al. / Composites: Part B 56 (2014) 670–672


STUDIES ON STRUCTURAL AND DIELECTRIC PROPERTIES OF CERIUM OXIDE

DOPED BARIUM STRONTIUM TITANATE (Ba0.5Sr0.5TiO3) CERAMICS

P. SREENIVASULA REDDY1, T. RANJETH KUMAR REDDY

2 & T. SUBBA RAO

3

1,3Department of Physics, S. K University, Anantapur, Andhra Pradesh, India

2Department of Physics, SRIT Engineering College, Ananatapuramu, Andhra Pradesh, India

ABSTRACT

Cerium oxide doped (0.05%, 0.10%, 0.15% and 0.20%) barium strontium titanate (Ba0.5Sr0.5TiO3 (BST50))

ceramic sample were prepared by solid-state reaction method. The structure of Cerium oxide doped BST50 was studied by

XRD. From the XRD data the lattice parameter a, particle sizes and unit cell volume were calculated. As a function of

frequency and temperature, dielectric properties were studied in the frequency range 1 kHz to 1 MHz.

KEYWORDS: X-Ray Diffraction, Dielectric Constant, Lattice Constant

INTRODUCTION

The general formula of perovskite is ABO3; the oxidation states of A, B and O are 2+, 4+ and 2- respectively.

Barium strontium titanate is also belongs to the perovskite family [1, 2]. Barium strontium titanate (BST) based ceramics

are chosen because of its several industrial applications, including dynamic random access memory capacitor [3, 4],

microwave filters, infrared detectors, and dielectric phase shifters [5-7], due to their excellent ferroelectric, dielectric,

piezoelectric and pyroelectric properties

PREPARATION OF SAMPLES

Cerium oxide doped (0.05%, 0.10%, 0.15% and 0.20%) barium strontium titanate (BST50) ceramic sample was

synthesized using a solid-state reaction method [8–11]. Reagent grade, BaCO3, SrCO3, TiO2 and CeO2 powders were used

as starting materials. The powders were mixed by ball milling for 20h for uniform mixing. The mixed powders were

calcined at 1200 - 12500C for 24h. After calcining the samples are ballmillied for 24h. Fine calcined powders were pressed

into disc-shaped pellets at an isostatic pressure of 10 tons. No binder was used. The pellets are sintered at 12800C. To find

out the properties, silver paste applied to it on both surfaces the sintered samples. The dielectric properties were measured

using HOCI LCR HITESTER-3532-50 meter at 1 kHz– 1 MHz from 300C to 300

0C.

DIELECTRIC MEASUREMENTS

Dielectric capacitance (c) dielectric and loss (tan δ) of the samples were measured in the frequency range 1 kHz to

1MHz using LCR meter (HIOKI 3532-50 LCR Hi Tester). Temperature variation of dielectric and dielectric loss were

studied at different frequencies (viz. 1 kHz, 10 kHz, and 100 kHz and 1 MHz). The dielectric constant (εr) was calculated

using the relation:

International Journal of Nanotechnology

and Application (IJNA)

ISSN(P): 2277-4777; ISSN(E): 2278-9391

Vol. 4, Issue 4, Aug 2014, 45-48

© TJPRC Pvt. Ltd.

http://www.tjprc.org/

46 P. Sreenivasula Reddy, T. Ranjeth Kumar Reddy & T. Subba Rao


Where c = the capacitance of the pellet,

t= the thickness of the pellet,

A= the area of cross section of the pellet and

εo is the permittivity of free space (8.854×10−12 F/m).

RESULTS AND DISCUSSIONS

Crystal Structure

Figure 1 shows the x-ray diffraction patterns of BST50 and Cerium oxide doped (0.05%, 0.10%, 0.15% and

0.20%) BST50 ceramics. The peak sharpness and intensity indicate that BST is fully crystalline. No impurity peaks was

observed in the XRD patterns. From XRD pattern we conformed that the structure of the Cerium oxide doped

(0.05%, 0.10%, 0.15% and 0.20%) BST50 is cubic structure.

The lattice parameter of Cerium oxide doped BST 50 is 3.9822A0. The volume of unit cell and average particle

sizes of Cerium oxide doped BST50 are 63.1494 cm3 and 20 to 90 nm respectively.

Dielectric Constant and Dielectric Loss

Variation of dielectric constant with frequency for CeO2 doped and BST50 at room temperature is shown in

Figure 2. The dielectric constant decrement was observed for 0.05% CeO2 doped composition. Further the dielectric

constant is increased up to 0.15% and then decreased.

When the Ce4+

(ionic radius 1.01 Ao) replaces Ti

4+ (ionic radius 0.68 A

o), the decreasing the amount of

spontaneous polarization will occur, which will explain the decrease of the permittivity with increasing Ce4+

ion

concentration. This is in agreement with the previous published work [12-19].

Variation of dielectric loss with frequency for CeO2 doped and BST50 at room temperature is shown in Figure 3.

At lower frequencies tan δ is large and it decreases with increasing frequency. The tan δ is the energy dissipation in the

dielectric system, which is proportional to the imaginary part of dielectric constant ε. At higher frequencies the losses are

reduced and the dipoles contribute to the polarization.

Figure 1: XRD Patterns of the 0.05%, 0.10% and 0.20% Wt% Ceo2 Doped BST50 Ceramics

Studies on Structural and Dielectric Properties of Cerium Oxide Doped 47

Barium Strontium Titanate (Ba0.5sr0.5tio3) Ceramics


Figure 2: Variation of Dielectric Constant with Frequency for

CeO2 Doped and BST50 at Room Temperature

Figure 3: Variation of Dielectric Loss with Frequency for CeO2 Doped and BST50 at Room Temperature

CONCLUSIONS

Cerium oxide doped (0.05%, 0.10%, 0.15% and 0.20%) barium strontium titanate (BST50) ceramics prepared by

high temperature solid reaction technique. It exhibit good homogeneity, small particle size and formation of single phase

compounds with cubic structure. The dielectric constant decrement was observed for CeO2 doped composition. +

REFERENCES

1. N. Setter, Electroceramics: looking ahead, J. Eur. Ceram. Soc.21 (2001) 1279.

2. N. W. Thomas, J. Phys. Chem. Solids 51 (12) (1990) 1419.

3. Scott, J. F. Ann. Rev. Mat. Sci. 28 (1998) 79.

4. Takasu, H. J. Electroceram. 4 (2000) 327.

5. Verbitskaja, T. N., Variconds. and Gosenergoizdat, Moscow-Leningrad; 1958 [in Russian].

6. Vendik, O. G, ed, Ferroelectrics in microwave engineering. Sov. Radio, Moscow, 1979 [in Russian].

http://www.tjprc.org/

48 P. Sreenivasula Reddy, T. Ranjeth Kumar Reddy & T. Subba Rao


7. Chang, W. and Sengupta, L. C, J Appl Phys. 92 (2002) 3941.

8. S. K. Rout, J. Bera, in: A. P. Tandon (Ed.), Ferroelectrics and Dielectrics, Allied Publishers Pvt. Ltd, New Delhi,

2004, pp. 3–7.

9. C. Fu, C. Yang, H. Chen, Y. Wang, L. Hu, Mater. Sci. Eng. B 119 (2005) 185.

10. O. P. Thakur, C. Prakash, D. K. Agarwal, Mater. Sci. Eng. B 96 (2002) 221.

11. R. Rai, N.C. Soni, S. Sharma, R.N.P. Choudhary, in: A. P. Tandon (Ed.), Ferroelectrics and Dielectrics,

Allied Publishers Pvt. Ltd., New Delhi, 2004, pp. 177.

12. Bockrath, M, Liang, W. J, Bozovic, D, Hafner, J. H., Lieber, C. M., Tinkham, M. and Park, H. K. Science, 291

(2001), 283

13. Boxter, P, Hellicar, N. H. and Lewis, B. J. Am. Ceram. Soc. 42 (1959) 465

14. Makishima, S, Hasegawa, K. and Shionoya, S. J. Phys. Chem. Solids, 23 (1962) 749

15. Paunovic, V, Zivkovic, L, Vracar, L, Mitic, V. and Miljkovic, M. Serbian J. Electrical Engineering, 1, 3 (2004),

89

16. Sierro, J. Helv. Phys. Acta, 34 (1961) 404

17. Verbitskaia, T. N, Zhdanov, G. S, Nenertsev, Iu. N. and Soloviev, S. P. Soviet Physics Crys. 3 (1958) 182

18. Vittayakorn, N. J. Appl. Sci. Res, 2 (2006) 1319

19. Xinyou, H, Chunhua, G, Xiangchong, C, Huiping, L, Guojun, H. and Xialian, Z. J. Rare Earths, 22, (2004) 219

Predittion

' , ',. " ii l,,i'

.4;i111 ;'1,;;' ,f .+ ', : t

,tillot.r-l' ,, ,, ,, ,,,,, ]1.- .,

t,".r"'t','-''

.:. .ttt' .,

;'"

"

"''"",.:"1",

:-i':"t;',*ry*"+ii'i+ri* rri""ii:r"'*"*"rili " "r:

";:iil,':*;":." :*:", n.r;;'r.':*:'i#r:,;i:I$i,ii:r,llrd$|#lltl:;ll ij: :, ri":;J lfi"'xxl'

ffiffi**f,slffifm+**i*:t*ft?d::.iTS{.H.ilfi t*li','H

u_I

rii,"gq,*;; r

"' :.:*::ili;ul't?lJl;:;i'lll:i?"f iiT::'-il.ir:.11.:,1'l;1. l';;1fl llllllli,;,H!;;:i li: :Ili: i;".iliii:;,"lli,ii:li li" il l ";

jj :il' *" :;:.ljl; F)r'lii:r":";t

.ti,fi ,l: l":1""J'1"";:llll j' 'ji: 'i'.:li::":;i1;]l'-1 ;:iilil ifl'.Ifi.:i:i;i:;l

" #'Ti$:"'**I;*l i'5i:,;Y::'d

,,$* d:*$isii,,ffi9u955"t15['#i:0,],,;i,;i' ii*riii ;.rr':r"'":; r*,

' .li#:;#.:.#.r t.",".-'

@il*i6"Jfi1f l:i:*H::'11:-i'J;Hiijlh*s$:#1"it:+*f;li-"e'-'

lil iH. tfo r r ::-,"';*:tr;1::-:,,Tl:l",Ji:L',lf ":ff ':sr" ;i

.,.,'.r-, ".:l;F:"I !l:5n :nt"1

" :# iiii]I-)']F#:*iffi;;r;:r", ir 'S.,.*". *"",.^-.. , ",*

l !npd( t S t rengr l ' xnd Dre le i l r i c S l rc r l rhC15$ Pdbc ie r H lb r id

L ' t - , k | 1 : t ' \ a n t . . : ' ^ n '

of corv dung Porvder flllcd

1. Renj.rb l(mu Rcddy' r' strbbr r&0r, rL P'dm' sntrnrrud itr Ashok xurtt

, D+q,,.!,, .t n) !L\ stu L,.o'ntttt,"":ll{:.,':y:,::'::::' . .1; . . :

I . " r t i - - - : ' . . "' r : ; : , . i , , , , : J; , i , , t ; , , , 1

.)h\libt. ttttu <ha4,n! )n\d \n

, ; - " " , r r r i - . ", * ; - r . ; - " . " d " F d . { - ' r i b ' - ! ' " '

r ; . . - . r . d b " " B F - . ' h a i "

; *i. u-- -i ),.q rib. -.@""i *'s *-""

, c m n r i F l . r [ c ! o e { !

" " ! . d . d d

o ! j h a d l o , . r i o "

t r * i ! - d i n e d o o " i j c d [ ! * . 1 " ' . , ' * . .

v i j h i g h n N t $ l , i o c

..-^-ia of - "" "r. Pd..tr. "ih

-*' r"'Fh; irc :esd 4 b b, rt ncsEioodrsre (r rI* . 4 $ ! . { d l ] o N q l t ( t r i J j + I i g u i t ri r *a- i " , tu . - .F . . " - r 'u r " r ' " *Fh;' NiEr ld. {erd t1 [ol

L

| q h f u j g b l l h { m . ' r ] . f t { k b g o u e d i t $ s g c

:

nD ro @oE or ntF4 nlrdzr lod kij chror,c L u d d q o q h L y h ! 6 [ c d q l ' . u i & i e d D u d q'he sq ft! mc &r rrE grcr .\tspd $Eid dr u,

Mdh,]! 'ht]kocPcorlde6&4LIidsdcdJt

l * J i e A / h ! u ] i ! i h J . d P , b d h $ s . L } d

h di prced lok d. snF;5 \!rc F+si b!

roy6gadiDtroEddst' ' l@c!tdtrdh6.rdioo! r mr25 rds hy lcigll upldh y lerlorduqir

rekEbr d idir diri Ldq! Fu 4 r% by rrc;88

6 . b d i * n f u h n F u d b b , h e 4 N U ' 1 h ! i b q n

hfibr r b irn !6! $e b,Dnd tuDp6 tr5 !r roF. b

5 d 4 s o . 3 l J e * d D s E 6 . d e d P d y s b | y ' d

ll*6bsoog!@3r'onah[t! lb{' ' lccli0]jm!io1orhcoi-9erhLros tue 6c,ufae ordE m! dos 6&rnry & E+oE6r ror dc totsiqis d rk srri{.! { e 6 d 4 ] ' ' h . b o i d f r g I i o F o d , l i b . . e [ L { l i

F c L F ( k i 8 l ' i b @ 4 o \ r o ! * %

dcrD&.'t5'(! ' ida\dug.i!rN.jsildNn,

f t;l ::

Fl s v. hrr, Lr Drol a(. @di. r rdcrEi, rFr(4d,rrrj,;,in,,r**''s v 4 ! i g e | 3 R d * o $ i : @ d s ' f t ! D 6 ' J ? 4 1,rF rb r(ierr0r r06q.

i"fi:f' " **

" stiiqs PorF '' r(''e

.ary P4 |4a6).rxa

kiit,cw Pa4 B !\xrd)\*2d

lLrl L. oLU! ai s riolr, De4 Jrd rAr r 1r)4!n.

j 3 { I 0 | 3 t r 7

i4le.. ical. l- ,4:dL€,1:qiJ|tr | i \n o l H l o n ! 9 \ } 1 1 8 d f u ( f o n q . j . n f 4 { d

\ { h i o r r 4 i { t . s . r ' E 4 E d o s a h

..rt ..b;,jtu bv6t '..rFrt1tt|ca, *hs % 6. , ' , r v a | ' . . r 1 ! ^ | . @ l ' , b

ini * rt- h%-; ATmrti u,:.fu I rcruItttfnl !ft

qoFdEsJd(un3fugdodsEM4dsi3sudcd

r !rr. rltr3 l - f t

HARDNESS, CHEMICAL RESISTANCE AND VOID CONTENT OF REINFORCED COW DUNG- GLASS FIBER...

Documents

Transcript of HARDNESS, CHEMICAL RESISTANCE AND VOID CONTENT OF REINFORCED COW DUNG- GLASS FIBER...