/Journal of Reinforced Plastics and Composites/content/30/19/1621The online version of this article can be found at:DOI: 10.1177/07316844114268102011 30: 1621 originally published online 7 November 2011Journal of Reinforced Plastics and Composites N. Venkateshwaran, A. ElayaPerumal and M. S. JagatheeshwaranEffect of fiber length and fiber content on mechanical properties of banana fiber/epoxy compositePublished by: can be found at:Journal of Reinforced Plastics and Composites Additional services and information for/cgi/alerts Email Alerts:/subscriptions Subscriptions: /journalsReprints.nav Reprints:/journalsPermissions.nav Permissions:/content/30/19/1621.refs.html Citations:What is This?- Nov 7, 2011OnlineFirst Version of Record- Dec 16, 2011Version of Record >>ArticleEffect of fiber length and fiber contenton mechanical properties of banana fiber/epoxy compositeN.Venkateshwaran,A.ElayaPerumal and M.S.JagatheeshwaranAbstractThe main factors that influence the properties of composite are fiber length and content.Hence the prediction of optimum fiber length and content becomes important,so that composite can be prepared with best mechanical prop-erties.Experiments are carried out as per ASTM standards to find the mechanical properties namely,tensile strength and modulus,flexural strength and modulus,and impact strength.In addition to mechanical properties,water absorption capacity of the composite is also studied.Further,fractured surface of the specimen are subjected to morphological study using scanning electron microscope.The investigation revealed the suitability of banana fiber as an effective reinforce-ment in epoxy matrix.Keywordspolymer composites,banana fiber,mechanical properties,scanning electron microscopeIntroductionNowadays,polymers are used everywhere in the day-to-day life.Plastics found its way when the need for low weight high strength material became important for various applications.The research in thefield of poly-mer and polymer-based components has gained wide-spread recognition owing to its property;however,its bio-degradability is still a matter of concern.Further, glassfiber reinforced polymers(GFRP)have become appealing substitutes for aluminum,concrete,and steel due to its high strength-to-weight ratio,ease of handling,and for being corrosion-free.Moreover, they can also be engineered to get the desired proper-ties.1Since large-scale production and fabrication of glassfiber causes environmental problems and also health hazards,a suitable alternate which is environ-mental friendly is the need of the hour.Naturalfibers that are low cost,lightweight and environmental friendly provide an excellent alternative to glassfiber. Joshi et al.2reviewed the life cycle assessment of natural fiber and glassfiber composite and found that natural fibers are environmentally superior to glassfiber,and also reduces the polymer content as reinforcement. Schmidt and Beyer,Wotzel et al.,and Corbiere et al.carried out some important works using the natural fibers as reinforcement in polymer matrix for use in automobile parts.Schmit and Beyer3have replaced the glassfiber polypropylene(PP)with hemp-PP com-posite for auto-insulation application.Wotzel et al.4 have used hemp-epoxy to replace glassfiber acryloni-trile butadien–styrene(ABS)for usage in auto-side panel.Similarly,Corbiere et al.5replaced glassfiber PP with Curaua PP for transporting pallet.All these studies revealed that the naturalfiber based polymer composite has successfully replaced the glassfiber. Pothan et al.6studied the effect offiber length and con-tent on the mechanical properties of the short banana/ polyester composite.Study shows that30–40mmfiber length and40%fiber loading provides better mechan-ical properties.Idicula et al.7investigated the mechan-ical performance of banana/sisal hybrid composite and Department of Mechanical Engineering,Anna University,Chennai,India.Corresponding author:N.Venkateshwaran,Department of Mechanical Engineering,Anna University,Chennai,IndiaEmail:venkatcad@Journal of Reinforced Plasticsand Composites30(19)1621–1627!The Author(s)2011Reprints and permissions:/journalsPermissions.navDOI:10.1177/0731684411426810the positive hybrid effect for tensile strength was found to be in the ratio of4:1(banana:sisal). Further,the tensile strength of the composite is better when bananafiber is used as skin and sisal as core material.Visco-elastic property of the banana/ sisal(1:1ratio)hybrid composite was studied by Idicula et al.8The study shows that sisal/polyester composite has maximum damping behavior and high-est impact strength as compared to banana/polyester and hybrid composite.Sapuan et al.9prepared the composite by reinforcing woven bananafibers with epoxy matrix.Tensile test result showed that the woven kind of reinforcement has better strength and the same was confirmed using Anova technique also. Venkateshwaran and ElayaPerumal10reviewed the various work in thefield of bananafiber reinforced with polymer matrix composite with reference to phys-ical properties,structure,and application. Venkateshwaran et al.11studied the effect of hybridi-zation on mechanical and water absorption properties. Investigation revealed that the addition of sisal in bananafiber composite upto50%increases the mechanical properties.Sapuan et al.12designed and fabricated the household telephone stand using woven banana fabric and epoxy as resin.Zainudin et al.13studied the thermal stability of banana pseudo-stem(BPS)filled unplastisized polyvinyl chlo-ride(UPVC)composites using thermo-gravimetric analysis.The study revealed that the incorporation of bananafiller decreases the thermal stability of the composite.Zainudin et al.14investigated the effect of bananafiller content in the UPVC matrix.The inser-tion offiller increases the modulus of the composite and not the tensile andflexural strength.Zainudin et al.15studied the effect of temperature on storage modulus and damping behavior of bananafiber rein-forced with UPVC.Uma Devi et al.16studied the mechanical properties of pineapple leaffiber rein-forced with polyester composite.Study found that optimum mechanical properties are achieved at 30mmfiber length and30%fiber content.Dabade et al.17investigated the effect offiber length and weight ratio on tensile properties of sun hemp and palmyra/polyester composite.The optimumfiber length and weight ratio were30mm and around 55%,respectively.From the above literatures,it is evident that the fiber length and content are the important factors that affect properties of the composite.Hence in this work,the effect offiber length and weight percentage on the mechanical and water absorption properties of the bananafiber epoxy composite is investigated. Further,the fractured surface of the composite are subjected to fractography study to evaluate the frac-ture mechanism.ExperimentalFabrication of compositeA molding box made of well-seasoned teak wood of dimensions300Â300Â3mm3is used to make a com-posite specimen.The top,bottom surfaces of the mold and the walls are coated with remover and kept for drying.Fibers of different length(5,10,15,and 20mm)and weight percentage(8,12,16,and20)are used along with Epoxy(LY556)and Hardener (HY951)for the preparation of composite.Testing standardsThe tensile strength of the composite was determined using Tinnus Olsen Universal Testing Machine (UTM)as per ASTM D638standard.The test speed was maintained at5mm/min.In this case,five specimens were tested with variedfiber length andfiber weight ratio.The average value of tensile load at breaking point was calculated.Theflexural strength was determined using the above-mentioned UTM as per ASTM D790procedure.The test speed was maintained between1.3and1.5mm/min. In this case,five samples were tested and the average flexural strength was reported.The impact strength of the composite specimen was determined using an Izod impact tester according to ASTM D256 Standards.In this case,five specimens were tested to obtain the average value.Figures1to5show the effect offiber length and weight content on ten-sile,flexural,and impact properties.Water absorp-tion behavior of banana/epoxy composites in water at room temperature was studied as per ASTM D570to study the kinetics of water absorption. The samples were taken out periodically andFigure1.Effect of fiber length and weight percentage on tensile strength.1622Journal of Reinforced Plastics and Composites30(19)weighed immediately,after wiping out the water from the surface of the sample and using a precise 4-digit balance to find out the content of water absorbed.All the samples were dried in an oven until constant weight was reached before immersing again in the water.The percentage of moisture absorption was plotted against time (hours)and are shown in Figures 6–13.Scanning electron microscopeThe fractured surfaces of the specimens were exam-ined directly by scanning electron microscope Hitachi-S3400N.The fractured portions of the sam-ples were cut and gold coated over the surface uni-formly for examination.The accelerating voltage used in this work was 10kV.Figures 14to 17show the fractured surface characteristics of the compositespecimen.Figure 6.Effect of moisture on fiber content;Fiber length –5mm.Figure 3.Effect of fiber length and weight percentage on flexural strength.Figure 2.Effect of fiber length and weight percentage on tensilemodulus.Figure 4.Effect of fiber length and weight percentage on flexuralmodulus.Figure 5.Effect of fiber length and weight percentage on impact strength.Venkateshwaran et al.1623Figure 12.Effect of moisture on fiber length;Fiber wt%–16.Figure 7.Effect of moisture on fiber content;Fiber length –10mm.Figure 11.Effect of moisture on fiber length;Fiber wt%–12.Figure 10.Effect of moisture on fiber length;Fiber wt%–8.Figure 8.Effect of moisture on fiber content;Fiber length –15mm.Figure 9.Effect of moisture on fiber content;Fiber length –20mm.1624Journal of Reinforced Plastics and Composites 30(19)Results and discussion Mechanical propertiesFor the tensile test,composite specimens are made of fibers of different length (5,10,15,and 20mm)and weight ratio (8,12,16,and 20)were used to calculate the tensile strength.Figures 1and 2show the effect of fiber length and weight ratios on tensile strength and modulus of the composite,respectively.Figure 1shows that the increase in fiber length and weight ratio increases the tensile strength and modulus upto 15mm fiber length and 12%weight ratio.Further increases cause the properties to decrease because of lower fiber–matrix adhesion and the quantity of fiber content being more than matrix.From Figures 1and 2,the maximum tensile strength and modulus oftheFigure 14.SEM micrograph of tensile fracturedspecimen.Figure 15.SEM micrograph of fractured specimen under flexuralload.Figure 16.SEM micrograph of fractured specimen under impactload.Figure 17.Micrograph of poorinterface.Figure 13.Effect of moisture on fiber length;Fiber wt%–20.Venkateshwaran et al.1625composite are16.39MPa and0.652GPa,respectively for thefiber length of5mm and12%weight ratio. Flexural strength and modulus for differentfiber lengths(5,10,15,and20mm)and weight ratios(8, 12,16,and20)are shown in Figures3and4,respec-tively.It was found that the maximumflexural strength and modulus are57.53MPa and8.92GPa,respectively for thefiber length of15mm andfiber weight of16%.The results of the pendulum impact test are shown in Figure 5.As thefiber weight and length increases impact strength also increases upto16%fiber weight ratio and then begin to decrease.The maximum impact strength of 2.25J/m was found for thefiber length 20mm and16%fiber weight.Although the variousfiber lengths and weight per-centage provides the maximum mechanical properties, from Figures10,12,and14it can be concluded that the optimumfiber length andfiber weight percentage is 15mm and16%respectively as the properties variation with15mm and16%are negligible when compared to the maximum mechanical properties provided by differ-entfiber lengths and weight percentage indicated as above.The mechanical properties provided above are better than coir18and palmyra.19Water absorption studyThe effects offiber length and content on the water absorption study are shown in Figures6–13.Figures 6to9show the effect offiber content on the water absorption property of the banana/epoxy composite. It shows that as thefiber content increases the moisture uptake of the composite also increases.This is due to the affinity of the bananafiber towards the moisture. The maximum moisture absorption for the composite is around5%for all length and weight percentage of composite.Figures10to13show the effect offiber length on the water uptake capability of composite.It indicates that the variation of length(5,10,15,and 20mm)does not have much impact as compared with thefiber content.The moisture absorption percentage of bananafiber/epoxy composite seems to be lesser than hempfiber20andflaxfiber21composite. Fractography studyMicrographs of fractured tensile,flexural,and impact specimens are shown in Figures14–17.Figure14shows the micrograph of fractured surface of specimen under tensile load.It clearly indicates that the failure is due to fiber pull out phenomenon.Figure15shows the frac-tured surface of the specimen under bending load. Micrograph also shows the bending offibers due to the application of load.Figure16shows the failure of the composite under impact load.Further,it also shows the striation occurring on the matrix surface and the presence of hole due tofiber pull out.Figure17shows the micrograph of20mmfiber length and20%fiber weight composite specimen.It clearly indicates that the clustering offibers result in poor interface with matrix,and in turn decreases the mechanical properties of the composite.ConclusionBased on thefindings of this investigation the following conclusions can be drawn:.The optimumfiber length and weight ratio are 15mm and16%,respectively for bananafiber/ epoxy composite..Moisture absorption percentage of banana/epoxy composite for all length and weight percentage is around5..Also,the moisture uptake capability of the compos-ite is greatly influenced byfiber content than length. .SEM image shows that increasing thefiber content above16%results in poor interface betweenfiber and matrix.References1.Houston N and Acosta F.Environmental effect of glassfiber reinforced polymers.In:Proceedings of2007Earth Quake Engineering Symposium for Young Researcher, Seattle,Washington,2007.2.Joshi SV,Drzal LT,Mohanty AK and Arora S.Are nat-ural fiber composites environmentally superior to glass fiber reinforced posite Part A2004;35: 371–376.3.Schmidt WP and Beyer HM.Life cycle study on a naturalfiber reinforced component.In:SAE Technical Paper 982195.SAE Total Life-Cycle Conference,1–3 December,1998,Graz,Austria.4.Wotzel K,Wirth R and Flake R.Life cycle studies onhemp fiber reinforced components and ABS for automo-tive parts.Die Angewandte Makromolekulare Chemie1999;272:121–127.5.Corbiere-Nicollier T,Laban BG and Lundquist.Lifecycleassessment of bio-fibers replacing glass fibers as reinforce-ment in plastics.Resour Conserv Recycl2001;33:267–287.6.Pothan LA,Thomas S and Neelakantan NR.Shortbanana fiber reinforced polyester composites:mechanical, failure and aging characteristics.J Reinf Plast Compos 1997;16:744–765.7.Idicula M,Neelakantan NR and Oommen Z.A study ofthe mechanical properties of randomly oriented short banana and sisal hybrid fibre reinforced polyester compos-ites.J Appl Polym Sci2005;96:1699–1709.1626Journal of Reinforced Plastics and Composites30(19)8.Idicula M,Malhotra SK,Joseph K and Thomas S.Dynamic mechanical analysis of randomly oriented short banana/sisal hybrid fibre reinforced polyester pos Sci Technol2005;65:1077–1085.9.Sapuan SM,Leenie A,Harimi M and Beng YK.Mechanical property analysis of woven banana/epoxy composite.Mater Design2006;27:689–693.10.Venkateshwaran N and ElayaPerumal A.Banana fiberreinforced polymer composite-a review.J Reinf Plast Compos2010;29:2387–2396.11.Venkateshwaran N,ElayaPerumal A,Alavudeen A andThiruchitrambalam M.Mechanical and water absorption behavior of banana/sisal reinforced hybrid composites.Mater Design2011;32:4017–4021.12.Sapuan SM and Maleque MA.Design and fabrication ofnatural woven fabric reinforced epoxy composite for household telephone stand.Mater Design2005;26: 65–71.13.Zainudin ES,Sapuan SM,Abdan K and MohamadMTM.Thermal degradation of banana pseudo-stem fibre reinforced unplastisized polyvinyl chloride compos-ites.Mater Design2009;30:557–562.14.Zainudin ES,Sapuan SM,Abdan K and MohamadMTM.The mechanical performance of banana pseudo-stem reinforced unplastisized polyvinyl chloride compos-ites.Polym Plast Technol Eng2009;48:97–101.15.Zainudin ES,Sapuan SM,Abdan K and MohamadMTM.Dynamic mechanical behaviour of bananapseudo-stem filled unplasticized polyvinyl chloride com-posites.Polym Polym Compos2009;17:55–62.16.Uma Devi L,Bhagawan SS and Sabu Thomas.Mechanical properties of pineapple leaf fiber-reinforced polyester composites.J Appl Polym Sci1997;64: 1739–1748.17.Dabade BM,Ramachandra Reddy G,Rajesham S andUdaya kiran C.Effect of fiber length and fiber weight ratio on tensile properties of sun hemp and palmyra fiber reinforced polyester composites.J Reinf Plast Compos 2006;25:1733–1738.18.Harish S,Peter Michael D,Bensely A,Mohan Lal D andRajadurai A.Mechanical property evaluation of natural fiber coir composite.Mater Characterisation2009;60: 44–49.19.Velmurugan R and Manikandan V.Mechanical proper-ties of palmyra/glass fiber hybrid posite Part-A2009;38:2216–2226.20.Dhakal HN,Zhang ZY and Richardson MOW.Effect ofwater absorption on the mechanical properties of hemp fibre reinforced unsaturated polyester composites.Compos Sci Technol2007;67:1674–1683.21.Alix S,Philippe E,Bessadok A,Lebrun V,Morvan V andMarais S.Effect of chemical treatments on water sorption and mechanical properties of flax fibres.Bioresour Technol2009;100:4742–4749.Venkateshwaran et al.1627。