Reinforcing Graphene Oxide Nanoparticles to Enhance Viscoelastic Performance of Epoxy Nanocomposites

7 Pages·03.986 MB·English

by  Suneev Anil Bansal1 ∗, Amrinder Pal Singh1 , and Suresh Kumar2 ∗

Article
Journalof
NanoscienceandNanotechnology
Copyright©2019AmericanScientificPublishers
Vol. 19, 4000–4006,2019
Allrightsreserved
PrintedintheUnitedStatesofAmerica www.aspbs.com/jnn
Reinforcing Graphene Oxide Nanoparticles to Enhance
Viscoelastic Performance of Epoxy Nanocomposites
Suneev Anil Bansal1(cid:2)∗, Amrinder Pal Singh1, and Suresh Kumar2(cid:2)∗
1DepartmentofMechanicalEngineering,UIET,PanjabUniversity,160014,Chandigarh,India
2DepartmentofAppliedSciences,UIET,PanjabUniversity,160014,Chandigarh,India
Graphene, two-dimensional (2D) sheet of carbon structure, in its purest form has shown poten-
tialforapplicationin thefieldsof electronics,semiconductor,sensing,energy,displays,biomedical
engineering,etc. Graphene oxide (GO) is easier to synthesise than the pristine graphene, scores
comparable in terms of mechanical strength, but lags in electrical and thermal conductivity. GO
playsanimportantroleinnano-compositesforuseinloadingconditionsrequiringsuperiormechan-
ical strength. GO is a suitable candidate as reinforcement due to its better solubility in the epoxy
polymer,resultinginimprovedproperties.Thepresentworkreportsthereinforcementofgraphene
oxide in epoxy matrix to enhance visco-elastic properties of the E-GO nano-composite. GO was
preparedbywet chemicaloxidationmethodfromgraphiteflakesthatwere usedasprecursor.The
E-GO nano-composite samples were prepared by solution mixing method, without the use of any
external stimulus to exclusively understand the effect of GO reinforcement. Dynamic mechanical
characterisationofthefabricatedE-GOnano-compositesforthevisco-elasticpropertieswascarried
outusing nano-indentationtechnique.Storagemodulusand loss modulusof the nano-composites
were tested over the frequency range of 20–200 Hz. Tan-delta or loss function was calculated
to characterise energy storage capacity of the nano-composite samples under the loading. Tan-
delta showed 12% improvement at 1 wt% of GO reinforcement in the nano-composite. Hardness
of the nano-composites improved upto 10% with GO reinforcement. Epoxy-based aircraft repair
applicationsrequireepoxy to deliver superiorelastic propertiesand the present report verifies the
improvementinelasticbehaviourof epoxywiththeadditionofGO.
Keywords: 2DMaterials,NanoCompositeMaterials,Epoxy,GrapheneOxide,Nanoindentation.
1. INTRODUCTION carbon atoms. Graphene, due to the thin sheet structure,
Sinceinception,carbon-basednanomaterials(CBNs)have has larger available surface area for bonding with matrix
been of great interest for enhancing mechanical, thermal, material. Due to the sheet-type structure having thickness
and electrical properties in nano-composites. CBNs pos- in the nano range, it is termed as a two-dimensional (2D)
sess exceptional mechanical, electrical, thermal, and elec- material.4 Graphene was first prepared by a very simple
tronic properties. Apart from fullerenes1 and nanotubes,2 mechanical cleavage-based scotch tape method3 and later
graphene3(cid:2)4 has emerged as a capable candidate in this various other methods to produce graphene were devel-
field since the beginning of this century, due to avail- oped. Challenge in the field of nano-compositesis to pro-
ability of large surface area for matrix material interac- duce GO nano sheets at a larger scale for enabling them
tion. The main difference between these three exceptional as potential replacement materials. Zhong et al. reviewed
materials is the structure of carbon atoms. Fullerenes are various graphene/graphene oxide (GO) production pro-
composed of carbon atoms, mostly in the form of hollow cesses and showed that scalable production of GO can
spheres. The nano-tubeshave cylindricalcarbonstructure. bedirectlyachievedbywetchemicaloxidationmethod.5–7
Graphene is just a single atom thin (or thick) sheet of Graphene is obtained by further reducing the GO, but
yield is reduced. GO has mechanical properties similar
∗Authorstowhomcorrespondence shouldbeaddressed. to graphene. GO as filler for enhancement of mechanical
4000 J.Nanosci.Nanotechnol.2019,Vol.19,No.7 1533-4880/2019/19/4000/007 doi:10.1166/jnn.2019.16336
Bansal et al. Reinforcing Graphene Oxide Nanoparticles toEnhance ViscoelasticPerformance of Epoxy Nanocomposites
strength of nano-composite has an advantage of scalable and CarbonFiber/Acrylonitrile-Butadiene-Styreneas filler
synthesis.Nanomaterialsaresuccessfullyusedtoenhance materials.26–29
mechanical properties of materials and there are various The present work is focused on the development
reports available in literature on thermo-set and thermo- of epoxy graphene-oxide (E-GO) nano-composites with
plastic polymer matrix-based composites reinforced with improved elastic properties by reinforcing 2-dimensional
GO/CBNs, developedfor mechanical applications.8–10 nano-GO in epoxy matrix. Highly-scalable production
Though thermo-set polymers are very brittle in nature, techniquesuitableforindustrialapplication,thewetchem-
the CBNs are able to improve the mechanical proper- ical oxidation method was used to synthesise the GO
ties considerably.9 Thermo-set polymers like epoxy are sheets.5 Low cost graphite flakes were used as precursor
versatile materials used as matrix material in the compos- material to synthesise the GO. Solution mixing method
ite fabrication and processing.11(cid:2)12 Epoxy has remarkable was used to synthesise E-GO nano-composite samples.
propertiesof superior heat resistance, chemicalresistance, E-GO nano-composite samples were prepared using dif-
electric insulation, mechanical strength (Elastic Modu- ferent weight percentages of GO as reinforcement. Pris-
lus 2.8 GPa), and thermal properties. The properties of tineepoxysampleswere also preparedforthe comparison
epoxycanbetunedtosuitmanyapplicationsinaerospace, of properties. UV-Visible, Raman spectroscopy, and XRD
marine, and automotive industry by appropriate choice of techniqueswereusedtocharacteriseGO.Morphologiesof
ahardenermaterialforitscuring.Epoxiesanditsproducts GO and E-GO nano-compositesamples were studied with
areusedinvariousformslikesandwichedcomposite,fiber scanning electron microscopy (SEM). Nano-DMA (DMA
reinforced composite, etc.13(cid:2)14 Static properties of epoxy usingnano-indentationtechnique)wasusedtocharacterise
canbesuccessfullyimprovedbyadditionofnano-particles the visco-elastic behaviour of E-GO nano-composite that
like GO,15 nano-clay,16 etc. The response of polymeric requiresaverysmallvolumeofsamplefortesting.Results
materials to external loading is a combination of elastic showed a considerable reduction in loss modulus, and
and viscous component. Viscous behaviour causes loss of improvementin hardness of E-GO nano-composites.
energy under the loading process due to plastic deforma-
tion, whereas elasticity in polymer stores the energy as
2. MATERIALS AND METHODS
in metals. This complex behaviour can be characterised
2.1. Materials
using dynamic mechanical analysis (DMA). DMA can be
Graphite flakes and Potassium permanganate (KMnO (cid:4)
performed on a material sample under loading by vary- 4
were purchased from Sigma Aldrich, India. Sulphuric
ing either temperature or frequency over a range. DMA
acid (H SO (cid:4), phosphoric acid (H PO (cid:4), hydrochloric
can be performedusing nano indentation,known as nano- 2 4 3 4
DMA for nano-scale characterisation of the dynamic per- acid (HCl), and hydrogen peroxide (H2O2(cid:4) were pur-
formance. Nano-DMA has minimal sample requirements chased from Fisher Scientific, India. Diglycidyl ether of
and yet it provides comparable results to the conven- bisphenol-A epoxy was purchased from Sigma Aldrich,
tional DMA.17 Few reports in literature are available on India. TETA (Tri-ethylenetetramine) was purchased from
the measurement of visco-elastic properties over a tem- Sisco Research Laboratories, India. All chemicals and
perature range based on material properties.18(cid:2)19 Margem regentsusedwereofhighpurityandanalyticalgrade(AR).
et al. studied visco-elastic behaviour of epoxy composites
reinforced with ramie fibers using DMA technique that 2.2. Synthesis of GO Nano Sheets
showedsofteningofepoxyafterthe reinforcement.20 Sim- GOnanosheetsweresynthesisedusingone-potwetchem-
ilar reports on DMA characterisation of epoxy compos- ical oxidation method.30 2 g of graphite flakes was mixed
ites to knowvisco-elasticpropertieswith reinforcementof withH SO :H PO 110ml:12mlsolutionina1Lborosil-
2 4 3 4
nano particles like epoxy-cyclohexyl-(POSS),nano-Al O icate glass container. The container carrying the solution
2 3
particles, (cid:3)-aluminum oxide, carbon nano-tubeshave also was placed on a magnetic stirrer at 600 rpm. After 5 min
been reported.21–25 Reinforcement of epoxy-cyclohexyl- of stirring, 12 g of KMnO was added at a very slow
4
(POSS), nano-Al O particles, (cid:3)-aluminum oxide, and rate of 1 g/5 min. Under acidic conditions, KMnO helps
2 3 4
carbon nano-tubes improved the dynamic behaviour of to oxidise graphite. After complete addition of KMnO ,
4
epoxy nano-composites. On the other hand, little work the colour of the solution changed from grey to green.
has been done to characterise epoxy-GOnano-composites The solution was kept on the magnetic stirrer for 3 days
at room temperature over a frequency range under load- and stirred continuously for oxidation. After 3 days, due
ing. The loading at varied frequency range at room to complete oxidation, the colour of the solution changed
temperature realistically simulates the actual mechanical to dark brown. The dark brown colour confirmed com-
loading of parts, e.g., in automobile and aircraft applica- pleteoxidationofthegraphiteflakes,resultinginincreased
tions. Recently, various reports have been published on viscosity of the solution. To stop the oxidation reaction,
epoxy-based composite using CNTs/ZnO, NH -Reduced 5 ml of H O was added. Addition of H O changed the
2 2 2 2 2
Graphene Oxide, Carbon Fibers with Carbon Nano-tubes colour of the solution to bright yellow that reconfirmed
J. Nanosci.Nanotechnol.19,4000–4006,2019 4001
Reinforcing Graphene Oxide Nanoparticles toEnhance ViscoelasticPerformance of Epoxy Nanocomposites Bansal et al.
complete oxidation. After the oxidation process, the solu- at 40 kV/40 mA. Scanning electron microscopy (SEM)
tionwaswashedrepeatedly,firstwith1MHCL,thenwith was performed on JEOL JSM-6100. The GO samples
deionised(DI)watertoachieveapHlevelof5–6.Solution were characterised using 25 KV accelerating voltage and
was centrifuged at 10,000 rpm and then sonicated using E-GOnano-compositespecimenswerecharacterisedusing
a probe sonicator (Qsonica Q700) to completely exfoliate 15 KV accelerating voltage of the SEM gun. The visco-
theGOsheetsintheDIwater.ToclaimGOindriedform, elastic characterisation of E-GO nano composite speci-
the solution was dried at 40 (cid:3)C overnightto evaporate DI mens was performed on HysitronTI-950 TriboIndenter.
water from it, leaving behind a thin film of GO. 1000(cid:5)NforcewasappliedonE-GOnano-compositesam-
ple during loading using Berkovich indenter. Frequency
2.3. Synthesis of E-GO Nano-Composite range of 20–200 Hz was used for testing, and the final
Liquid phase solution mixing method was used to syn- frequencywas reached in 15 steps.
thesise the GO-reinforcedepoxynano-compositesamples.
Freshly preparedGO 1 mg/ml was added to acetone solu-
3. RESULTS AND DISCUSSION
tion (Fisher Scientific) and sonicated with probe sonicator
3.1. GO Characterisation
for 30 mins. After complete dispersion of GO in the ace-
UV-Visible spectrum of GO (Fig. 1) showed the charac-
tone, diglycidylether of bisphenol-A epoxy was mixed in
teristic peak at 232 nm and a shoulder at 285 nm. The
the solution under constant stirring condition for 10 mins
spectrum was recorded for aqueous GO dispersion. Peak
at room temperature. For complete mixing and disper-
at 232 nm is (cid:6)–(cid:6)∗ plasomonic peak that determines the
sion, the solution was sonicated for 5 mins. In order to
degree of conjugation. The shoulder at 285 nm corre-
evaporateacetone completely,the temperatureof the mix-
ture was raised to 70 (cid:3)C. The mixture was then dried sponds to n→(cid:6)∗ transitions due to the presence of car-
boxyl group. Results are in agreement with the reported
under vacuum in an oven for 10 mins to ensure complete
literature.31 Raman spectrum of GO (in powdered form)
removal of acetone. The temperature of the solution was
lowered to 15 (cid:3)C and 15 PHR (parts per hundred resin) showed D peak at 1344 cm−1 and G peak at 1586 cm−1
ofamine-basedcuringagentTETA(Tri-ethylenetetramine) (Fig. 2). D band represents disorder of carbon structure
wasaddedandmixedcompletely.Thesolutionwasstirred andGbandrepresentsE2g mode(firstorder)fromsp2 car-
to removegasesproducedfromthe reaction.Beforesolid- bondomain.XRD spectrumofGO showedapeakat9.8(cid:3),
ification, the solution was poured in tablet-shaped moulds as shown in Figure 3. This peak corresponds to ∼0.9 nm
and left for 24 hrs at room temperature for solidifica- inter-planer spacing. This increase in inter-planer spacing
tion. Post curing was done at 90 (cid:3)C for 1 hr. Experiments (0.9 nm), as compared to that in graphite (0.34 nm), con-
wererepeatedin thecontrolledenvironmentwith different firmssynthesisofGO.BothRamanspectrumandtheXRD
epoxy to GO wt% ratios to fabricate the nano-composite resultsareinagreementwiththereportedliterature.32 Fur-
samples. Details of the specimen and the nomenclature ther,thesynthesisofGOsheetscanbeverifiedfromSEM
used are listed in Table I. images, shown in Figure 4(a). SEM figures clearly show
thewrinkledsheetsofGO withlargelateralsize.33 Allthe
2.4. Characterisation results are in line with the published literature.
UV-Visible spectroscopy of GO was performed using
Schimadzu UV2600 apparatus. The absorbance spectrum 3.2. E-GO Nano-Composite Characterisation
was recorded over a wavelength range of 200–500 nm. Figure 4(b) shows morphology of the nano-composite
The Raman spectroscopy of GO was carried out using sample surface. SEM images clearly show layers of poly-
Reinshaw Invia Raman microscope. Intensity of the spec- mer wrapping over the sheets of GO dispersed in the
trum was recorded over 1000 to 3000 cm−1 wave num- matrix. Blue arrows indicate different layers of polymer.
ber. The XRD spectrum of GO was recorded on Rigaku Densityofthelayersofpolymerissmoothandfairlyregu-
Ultima-IV by varying 2 theta from 0(cid:3) to 30(cid:3) in steps of lar, indicatingbetter dispersion.Epoxyused in the present
0.02(cid:3).RecordingofXRDspectrumwasdoneusingX-rays study was cured by using TETA. Red arrows show voids
TableI. Dynamicmechanicalproperties ofE-GOnano-composite samplesatvariousGOwt%reinforcement.
Dynamicmechanicalproperties
Avg.loss Avg.storage Avg.hardness
S.no. Specimensymbol Matrixmaterial GOwt%age modulus(GPa) modulus(GPa) (GPa) Tan-delta
1 E-GO#000 Epoxy 0.00 0.2039 5.2582 0.2807 0.038778
2 E-GO#050 Epoxy 0.50 0.1994 5.0175 0.3086 0.039741
3 E-GO#100 Epoxy 1.00 0.1776 5.1408 0.2916 0.034547
4 E-GO#150 Epoxy 1.50 0.2027 5.2962 0.2695 0.038273
4002 J. Nanosci.Nanotechnol.19,4000–4006,2019
Bansal et al. Reinforcing Graphene Oxide Nanoparticles toEnhance ViscoelasticPerformance of Epoxy Nanocomposites
Figure3. XRDspectrumofthesynthesisedGO.
Figure1. UV-VisiblespectrumofthesynthesisedGO.
apparatus was able to generate visco-elastic response of
producedduetoreleaseofgasesduringthecuringprocess.
thenano-compositesample.Thevisco-elasticbehaviourof
Size of the holes is in the order of few microns.
a material can be understood by dividing the mechanical
Visco-elasticpropertiesoftheE-GOcompositesamples
response into two parts. The first part is called storage
weretestedusingnano-DMAtechnique.Nano-DMAchar-
modulus(E(cid:6))thatrepresentstheabilityofthevisco-elastic
acterisesmaterialsusingresponseofmaterialtoastandard
materialto absorbenergyduringloading.The second part
pulsatingloadappliedonthespecimenbyanano-indenter.
is the loss modulus (E(cid:6)(cid:6)) that represents the ability of the
Moreover,visco-elasticpropertiesofmaterialslikestorage
material to dissipate energy duringloading. The two parts
modulus and loss modulus were characterised as time-
can be successfully represented mathematically in a com-
dependentphenomenonunderload.34Invisco-elasticmate- plexspace ascomplexmodulus(E∗), as shownin Eq. (1).
rials, the stress produced by the applied load on a sample
isnotsynchronisedwiththestraininducedinthematerial. Complex modulus E∗=E(cid:6)+iE(cid:6)(cid:6) (1)
The lag between stress developed and strain response of
To understand the visco-elastic behaviour, individual
visco-elastic material is due to part storage and dissipa-
values of E(cid:6) and E(cid:6)(cid:6) are required that can be calculated
tion of the energy during loading. Due to this, even after
from Eqs. (2) and (3), respectively, as:
removal of load from the sample, strain keeps on increas-
√
ing for a little more time. (cid:6) K
A pulsating load of 1000 (cid:5)N was applied on the sam- Storage modulus E(cid:6)= 2 √Ac (2)
ple surface. Embedded software package of TriboIndenter √
(cid:6) (cid:7)D
Loss modulus E(cid:6)(cid:6)= √ c (3)
2 A
where,Aiscontactareabetweentheindentertipandsam-
ple that depends on the indenter geometry, K is contact
c
stiffness, D is damping, and (cid:7) is the frequency.
c
Although individual values help in understanding the
visco-elastic behaviour of a material, relative change also
plays an important role. The relative change is repre-
sented by a loss factor called tan-delta ((cid:8)(cid:4) and is defined
as the ratio of E(cid:6)(cid:6) to E(cid:6), as shown in Eq. (4). It mea-
sures the energy lost during loading in terms of recover-
ableenergy.Largevalueof (cid:8) demonstratesthe non-elastic
behaviour of material, while smaller values represent the
elastic behaviour.
E(cid:6)(cid:6)
Tan Delta (cid:8)= (4)
E(cid:6)
The average behaviour over the 20–200 Hz frequency
Figure2. RamanspectrumofthesynthesisedGO. range of E-GO nano-composite samples is represented in
J. Nanosci.Nanotechnol.19,4000–4006,2019 4003
Reinforcing Graphene Oxide Nanoparticles toEnhance ViscoelasticPerformance of Epoxy Nanocomposites Bansal et al.
Figure4. SEMmicrographsofthesynthesised(a)GOsheets(b)E-GOnano-composite.
TableI.ThevariationinlossmodulusisshowninFigure5 Measure of the energy lost with respect to recoverable
and variation in tan-delta is represented in Figure 6. The energy is represented by loss factor tan-delta (Fig. 6).
average value of loss modulus for E-GO nano-composite Decrease in value of tan-delta is termed as an improve-
samplesimprovedfrom0.2039GPa for thepristine epoxy mentin the elastic propertiesof material. Smallreinforce-
to 0.1994 GPa at GO reinforcement of 0.5 wt%. During ment of 0.50 wt% of GO resulted in a marginal increase
loading and unloadingcycle, any permanentsettlement of in the value of tan-delta. Tan-deltavalue achievedoptimal
polymer chains leads to the loss of energy due to viscous 1.0wt%ofGO reinforcementintheepoxymatrix.Decre-
behaviour. SEM micrograph of E-GO composite showed ment in tan-delta value as result of reduced loss modu-
layered structure of epoxy over GO sheets. Under load- lus contributed to enhanced elastic response of the E-GO
ing, the GO undergoes elastic deformation and prevents nano-composites. The improvement in elastic response
permanent deformation of the matrix. This contributes to wasachievedduetolackinmobilityoftheepoxymolecu-
elastic recovery on the nano-composite after removal of lar chains. Lack in mobility was achievedby intercalation
the load, yielding improvement in the loss modulus. As of nano-phase GO in the epoxy matrix. High aspect ratio
thereinforcementofGOinepoxyincreased,thelossmod- of the GO in nano-composite also contributed to greater
ulusimprovedfurtherto 0.1776GPa at 1.0 wt% GO rein- interaction of GO with epoxy matrix. E-GO#100 speci-
forcement. Optimal value of loss modulus was achieved men(1.0wt%ofGO) showed∼12%improvementin tan-
at 1.0 wt% of GO reinforcement and further increasing delta as compared to E-GO#000 pristine sample. Further
the percentageof GO reinforcementreduced the improve- increasing the GO reinforcement beyond 1 wt% dimin-
ment in loss modulus values. In percentage term, there ished tan-delta improvementto 3.8%.
was ∼15% improvement in loss modulus for E-GO#100 Average values of hardness of E-GO nano-composite
sample at 1.0 wt% reinforcement of GO as compared to samples over the 20–200 Hz frequency range are shown
E-GO#000 pristine epoxy sample. in Table I and Figure 7. Improved hardness leads to
Figure5. Variation inaverage loss modulus of E-GOnano-composite Figure6. Variation in tan-delta of E-GO nano-composite samples at
samplesatvariousGOreinforcements. variousGOreinforcements.
4004 J. Nanosci.Nanotechnol.19,4000–4006,2019
Bansal et al. Reinforcing Graphene Oxide Nanoparticles toEnhance ViscoelasticPerformance of Epoxy Nanocomposites
• Loss factor (tan-delta) measuring the loss of energy to
recoverableenergyalso improvedby 12%, from0.038778
to 0.034547,using 1.0 wt% of GO as reinforcement.
• Apart from the visco-elastic properties, hardness of
E-GO nano-composites also improved with GO nano
fillers. At 0.5 wt% of GO reinforcement, the hardness of
nano-compositesimprovedby ∼10%.
Acknowledgments: We thank Dr. Inderpreet Kaur,
CSIO, Chandigarh, for Raman; Dr. Navin Kumar, IIT,
Ropar, for Nano-indentation; and Dr. Vinod Kumar,
DCRUST, Murthal, for XRD characterisation.
References and Notes
1. P. R. Buseck, S. J. Tsipursky, and R. Hettich, Science 257, 215
(1992).
Figure7. Variation in hardness of E-GO nano-composite samples at
2. S.Iijima,Nature354,56(1991).
variousGOreinforcements.
3. K. S. Novoselov, A. K. Geim, S. V Morozov, D. Jiang, Y. Zhang,
S.V.Dubonos,I.V.Grigorieva,andA.A.Firsov,Science306,666
(2004).
improved surface properties, widening the scope of appli- 4. S. A. Bansal, A. P. Singh, and S. Kumar, AIP Conf. Proc. (2016),
cations of epoxy nano-composites. Hardness increased to Vol.1728,p.20459.
5. Y.L.Zhong,Z.Tian,G.P.Simon,andD.Li,Mater.Today18,73
0.3086 GPa with small reinforcement of 0.5 wt% rein-
(2015).
forcementfrom0.2807GPaforthepristineepoxy.Further 6. S. Xu, J. Liu, Y. Xue, T. Wu, and Z. Zhang, Fullerenes, Nanotub.
reinforcement of GO decreased the hardness of nano- CarbonNanostructures25,40(2017).
composites. In percentage terms, hardness was improved 7. E.J.Frankberg, L.George, A.Efimov,M.Honkanen, J.Pessi,and
by ∼10% at 0.5 wt% reinforcementof GO. The hardness E. Levänen, Fullerenes, Nanotub. Carbon Nanostructures 23, 755
(2015).
of nano-composite sample was improved to 0.2916 GPa
8. A. Kausar, Z. Anwar, and B. Muhammad, Polym. Plast. Technol.
with 1.0 wt% of GO reinforcement, as compared to Eng.55,1192(2016).
0.2807 GPa for pristine epoxy corresponding to optimal 9. A. Kausar, I. Rafique, and B. Muhammad, Polym. Plast. Technol.
loss modulus and tan-delta. In addition to improvement Eng.55,1167(2016).
10. Y. Rostamiyan, A. Fereidoon, M. Rezaeiashtiyani, A. Hamed
in the visco-elastic properties, the GO reinforcement in
Mashhadzadeh, andA.Salmankhani,Mater.Des.69,96(2015).
epoxy also contributed towards improvement in hardness
11. A. P. Singh, M. Sharma, and I. Singh, Multidiscip. Model. Mater.
of E-GO nano-composites. Struct.10,346(2014).
12. A. P. Singh, M. Sharma, and I. Singh, Multidiscip. Model. Mater.
Struct.10,611(2014).
4. CONCLUSION 13. P.RawatandK.K.Singh,Polym.Compos.38,175(2017).
14. A.GauravandK.K.Singh,Polym.Compos.39,1785(2018).
The present work successfully demonstrated the role of
15. S.A.Bansal,A.P.Singh,A.Kumar,S.Kumar,N.Kumar,andJ.K.
carbon-structuredGO nano sheets in enhancingthe visco-
Goswamy,J.Compos.Mater.52,2179(2018).
elastic properties of the resulting nano-composites. The 16. L. Shen, L. Wang, T. Liu, and C. He, Macromol. Mater. Eng.
work concurrently studied the effect of GO reinforcement 291,1358(2006).
on hardness of E-GO nano-composites that can enhance 17. A.ChakravartulaandK.Komvopoulos,Appl.Phys.Lett.88,131901
(2006).
applications of the synthesised materials in aerospace
18. A.X.H.Yong,G.D.Sims,S.J.P.Gnaniah,S.L.Ogin,andP.A.
applications. Following conclusions are drawn from the
Smith,Adv.Manuf.Polym.Compos.Sci.3,43(2017).
presented work: 19. K. K. Kar, A. Rahaman, P. Agnihotri, and D. Sathiyamoorthy,
• A single pot wet chemical oxidation method was used Fullerenes,Nanotub.CarbonNanostructures17,209(2009).
20. F.M.Margem,S.N.Monteiro, J.B.Neto,R.J.S.Rodriguez, and
to synthesise the large sized GO sheets. The synthe-
B.G.Soares,Matéria(RioJaneiro)15,164(2010).
sised GO sheets were successfully used as reinforcement
21. V. Pistor, F. G. Ornaghi, H. L. Ornaghi, and A. J. Zattera, Mater.
in epoxy matrix (brittle material), resulting in improved Sci.Eng.A532,339(2012).
visco-elastic properties of nano-composites. 22. H. L. Ornaghi, V. Pistor, and A. J. Zattera, J. Non Cryst. Solids
• Loss modulus of E-GO nano-compositeswas improved 358,427(2012).
upto∼15%at1.0wt%ofGOreinforcement.Theoptimal 23. W. Jiang, F.-L. Jin, and S.-J. Park, J. Ind. Eng. Chem. 18, 594
(2012).
improvement was achieved using a small quantity (only
24. C.-H. Chen, J.-Y. Jian, and F.-S. Yen, Compos. Part A Appl. Sci.
1.00 wt%) of GO as reinforcement. Manuf.40,463(2009).
J. Nanosci.Nanotechnol.19,4000–4006,2019 4005
Reinforcing Graphene Oxide Nanoparticles toEnhance ViscoelasticPerformance of Epoxy Nanocomposites Bansal et al.
25. C.-F.Kuan,W.-J.Chen,Y.-L.Li,C.-H.Chen,H.-C.Kuan,andC.-L. 30. N. M. Huang, H. N. Lim, C. H. Chia, M. A. Yarmo, and M. R.
Chiang,J.Phys.Chem.Solids71,539(2010). Muhamad,Int.J.Nanomedicine 6,3443(2011).
26. P.G.Vu,T.A.Truc,N.T.Chinh,D.Q.Tham,T.H.Trung,V.K. 31. D.C. Marcano, D.V. Kosynkin,J.M.Berlin, A.Sinitskii, Z.Sun,
Oanh, T. T. X. Hang, M. Olivier, and T. Hoang, J. Nanosci. Nan- A. Slesarev, L. B. Alemany, W. Lu, and J. M. Tour, ACS Nano
otechnol.18,2830(2018). 4,4806(2010).
27. T.Jin,Y.Han,R.Bai,andX.Liu,J.Nanosci.Nanotechnol.18,4971 32. S. Kumar, R. R. Nair, P. B. Pillai, S. N. Gupta, M. A. R. Iyengar,
(2018). andA.K.Sood,ACSAppl.Mater.Interf.6,17426(2014).
28. L. Zhanjun, C. Hui, W. Jing, X. Xiaohong, L. Hongbo, and Y. Li, 33. S.Kellici, J.Acord,J.Ball,H.S.Reehal,D.Morgan,andB.Saha,
J.Nanosci.Nanotechnol. 18,4940(2018). RSCAdv.4,14858(2014).
29. C.Wang,H.Ge,X.Ma,Z.Liu,T.Wang,andJ.Zhang,J.Nanosci. 34. Y. Cao, X. Qian, and N. Huber, Mater. Sci. Eng. A 454, 1
Nanotechnol. 18,2513(2018). (2007).
Received: 26 April 2018. Accepted: 18 June 2018.
4006 J. Nanosci.Nanotechnol.19,4000–4006,2019