The epoxy-based glass fibre-reinforced polymers (GFRPs) were fabricated by adding three different graphene derivatives: anthracite coal-derived graphene oxide (AGO), commercial-grade graphene oxide (GGO), and commercial-grade reduced graphene oxide (GrGO). The composites having varying concentrations of nanofiller (0.075–0.3 phr), were prepared with hand layup using vacuum-assisted infusion molding setup. The results of the mechanical tests revealed that the AGO-reinforced composites showed the highest improvement at a concentration of 0.1 phr, with an increase of 27.6% in impact resistance, 27.1% in flexural modulus, and 11.7% in tensile strength. However, GGO and GrGO showed higher contents of 0.2 phr for maximum improvement. Structure-property correlations were carried out using FTIR, EDS, XRD, TEM and SEM. FTIR analysis revealed an increased relative abundance of oxygen functional groups in AGO, while EDS analysis revealed a decreasing trend of oxygen content (AGO > GGO > GrGO). The presence of remaining nitrogen-containing heteroatoms as reported in previous studies on coal-derived graphene oxide, can increase interfacial interactions. XRD and TEM analysis revealed improved exfoliation at optimal concentrations of GO, fracture surface analysis revealed improved matrix-fibre interactions and efficient crack-deflection. The findings of this study confirm that coal-derived graphene oxide is a low-cost nanofiller material for high-performance structural composites.
SinghKNandaTMehtaR. Processing of polyethylene terephthalate fiber reinforcement to improve compatibility with constituents of GFRP nanocomposites. Mater Manuf Process2018; 33: 165–173. https://doi.org/10.1080/10426914.2017.1291955
3.
SinghKNandaTMehtaR. Compatibilization of polypropylene fibers in epoxy based GFRP/Clay nanocomposites for improved impact strength. Compos Part A Appl Sci Manuf2017; 98: 207–217. https://doi.org/10.1016/j.compositesa.2017.03.027
4.
SinghKNandaTMehtaR. Addition of nanoclay and compatibilized EPDM rubber for improved impact strength of epoxy glass fiber composites. Compos Part A Appl Sci Manuf2017; 103: 263–271. https://doi.org/10.1016/j.compositesa.2017.10.009
5.
NandaTSinghKShellyD, et al.Advancements in multi-scale filler reinforced epoxy nanocomposites for improved impact strength: a review. Crit Rev Solid State Mater Sci2021; 46: 281–329. https://doi.org/10.1080/10408436.2020.1777934
6.
BoobalanVSathishTMadanAKL. Enhancing the morphological and mechanical performances of basalt/glass fiber/polymer composites modified with hybrid MWCNTs and SiO2 nanoparticles. Interactions. 2025; 246: 30. https://doi.org/10.1007/s10751-025-02255-2
7.
ShellyDNandaTMehtaR. Addition of compatibilized nanoclay to GFRCs for improved izod impact strength and tensile properties. Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications2021; 235: 2022–2035. https://doi.org/10.1177/14644207211009923
8.
ShellyDSinghKNandaT, et al. Addition of nanomer clays to GFRPs for enhanced impact strength and fracture toughness. Mater Res Express; 5: 105013. https://doi.org/10.1088/2053-1591/aadb0d
9.
ShellyDNandaTMehtaR. Addition of compatibilized nanoclay and UHMWPE fibers to epoxy based GFRPs for improved mechanical properties. Compos Part A Appl Sci Manuf; 145. https://doi.org/10.1016/j.compositesa.2021.106371. Epub ahead of print 1 June 2021.
10.
SathishTBoobalanVGiriP, et al.Enhancing flexural performance of basalt/glass fiber hybrid nanocomposites with MWCNTs+SiO2 nanoparticles by box-behnken design of RSM. In: 2024 IEEE 2nd International Conference on Emerging Trends in Engineering and Medical Sciences, Nagpur, India, 2024, Nov 22. ICETEMSInstitute of Electrical and Electronics Engineers Inc, pp.755–761.
11.
HarshaMSKumarVSHPrasadMB, et al.Synergistic effects of titanium dioxide and graphene nanofillers on delamination and thrust forces in machining glass fiber reinforced nanocomposites. Sci Rep2025; 15. https://doi.org/10.1038/s41598-025-92140-3, Epub ahead of print 1.
12.
ShellyDSinghalVSinghS, et al.Exploring the impact of nanoclay on epoxy nanocomposites: a comprehensive review. J Compos Sci2024; 8: 506. https://doi.org/10.3390/jcs8120506
13.
ShellyDNandaTMehtaR. Synergistic effect of compatibilized nanoclay/polyethylene fibers on the impact strength of epoxy-glass fiber nanocomposites. Polym Compos2023; 44: 6528–6541. https://doi.org/10.1002/pc.27577
14.
RafieeMNitzscheFLaliberteJ, et al.Thermal properties of doubly reinforced fiberglass/epoxy composites with graphene nanoplatelets, graphene oxide and reduced-graphene oxide. Compos B Eng2019; 164: 1–9. https://doi.org/10.1016/j.compositesb.2018.11.051
15.
KavimaniVStalinBGopalPM, et al.Application of r-GO-MMT hybrid nanofillers for improving strength and flame retardancy of epoxy/glass fibre composites. Adv Polym Technol2021. https://doi.org/10.1155/2021/6627743, Epub ahead of print 2021.
16.
SathishTSaravananRArunachalamSJ, et al.Effect of TiO2 in Jute/Kenaf/glass composite for interlaminar shear strength using RSM. In: 2024 IEEE 2nd International Conference on Emerging Trends in Engineering and Medical Sciences, Nagpur, India, 2024, Nov 22. ICETEMSInstitute of Electrical and Electronics Engineers Inc, pp. 779–784.
17.
MenbariSAshoriARahmaniH, et al.Viscoelastic response and interlaminar delamination resistance of epoxy/glass fiber/functionalized graphene oxide multi-scale composites. Polym Test2016; 54: 186–195. https://doi.org/10.1016/j.polymertesting.2016.07.016
18.
GargABasuSMehtaR, et al.Enhancing the mechanical performance of E-glass fiber epoxy composites using coal-derived graphene oxide. Polym Compos2024; 45: 2444–2461. https://doi.org/10.1002/pc.27931
19.
GargABasuSLeeSY, et al.Simplified one-pot synthesis of graphene oxide from different coals and its potential application in enhancing the mechanical performance of GFRP nanocomposites. ACS Appl Nano Mater2023; 6: 14594–14608. https://doi.org/10.1021/acsanm.3c03197
20.
FekiačJJKrbataMKohutiarM, et al. Comprehensive review: optimization of epoxy composites, mechanical properties, & technological trends. Polymers; 17(3): 271. https://doi.org/10.3390/polym17030271
21.
SinitskiiADimievAKosynkinDV, et al.Graphene nanoribbon devices produced by oxidative unzipping of carbon nanotubes. ACS Nano2010; 4: 5405–5413. https://doi.org/10.1021/nn101019h
22.
ZhangZZhangJLiS, et al. Effect of graphene liquid crystal on dielectric properties of polydimethylsiloxane nanocomposites. Compos B Eng; 176: 107338. https://doi.org/10.1016/j.compositesb.2019.107338
23.
ZhangGLiPZhaoW, et al.MXene Nanofluid-driven interfacial synergy for next-generation anisotropic conductive films. ACS Appl Mater Interfaces2025; 17: 55161–55171. https://doi.org/10.1021/acsami.5c16489
24.
ZhuWWangQZhangP, et al.The functional graphene/epoxy resin composites prepared by novel two-phase extraction towards enhancing mechanical properties and thermal stability. Front Chem2024; 12: 1–10. https://doi.org/10.3389/fchem.2024.1433727
25.
ZhangJXLiangYXWangX, et al.Strengthened epoxy resin with hyperbranched polyamine-ester anchored graphene oxide via novel phase transfer approach. Adv Compos Hybrid Mater 2017 1:22017; 1: 300–309. https://doi.org/10.1007/s42114-017-0007-0
26.
WangHPeiXShaoR, et al. Resistance of Graphene/epoxy resin—based composite materials to γ radiation damage and their mechanical properties. Coatings. 2023; 13: 1536. https://doi.org/10.3390/coatings13091536
27.
CaoLZhiJYangY, et al. Synergistically improving mechanical and interfacial properties of epoxy resin and CFRP composites by introducing graphene oxide. Adv Polym Technol. 2022; 2022: 8309259. https://doi.org/10.1155/2022/8309259
28.
ShellyDSinghalVNandaT, et al.A review of the emerging approaches for developing multi-scale filler-reinforced epoxy nanocomposites with enhanced impact performance. Polym Compos2024; 45: 9647–9676. https://doi.org/10.1002/pc.28479
29.
AradhanaRMohantySNayakSK. Comparison of mechanical, electrical and thermal properties in graphene oxide and reduced graphene oxide filled epoxy nanocomposite adhesives. Polymer (Guildf)2018; 141: 109–123. https://doi.org/10.1016/j.polymer.2018.03.005
30.
WisanrakkitGGillhamJK. The glass transition temperature (Tg) as an index of chemical conversion for a high‐tg amine/epoxy system: Chemical and diffusion‐controlled reaction kinetics. J Appl Polym Sci1990; 41: 2885–2929. https://doi.org/10.1002/app.1990.070411129
31.
YousefiNLinXZhengQ, et al.Simultaneous in situ reduction, self-alignment and covalent bonding in graphene oxide/epoxy composites. Carbon N Y2013; 59: 406–417. https://doi.org/10.1016/j.carbon.2013.03.034
32.
OlowojobaGBEslavaSGutierrezES, et al.In situ thermally reduced graphene oxide/epoxy composites: thermal and mechanical properties. Applied Nanoscience (Switzerland)2016; 6: 1015–1022. https://doi.org/10.1007/s13204-016-0518-y
33.
TangLCWanYJYanD, et al.The effect of graphene dispersion on the mechanical properties of graphene/epoxy composites. Carbon N Y2013; 60: 16–27. https://doi.org/10.1016/j.carbon.2013.03.050
34.
KumarASharmaKRaiA. Tensile, flexural and interlaminar shear strength of carbon fiber reinforced epoxy composites modified by graphene. Polym Bull2023; 80: 7469–7490. https://doi.org/10.1007/s00289-022-04413-w
35.
KumarASinghSVarshneyD, et al. Comparison of the tensile and flexural properties of epoxy nanocomposites reinforced by graphene oxide and reduced graphene oxide. Polymer Composites. 2025; 46(S): 835–845. https://doi.org/10.1002/pc.29875
36.
KumarASharmaKDixitAR. Review A review of the mechanical and thermal properties of graphene and its hybrid polymer nanocomposites for structural applications. J Mater Sci2019; 54: 5992–6026. https://doi.org/10.1007/s10853-018-03244-3
37.
KumarASharmaKDixitAR. Carbon nanotube- and graphene-reinforced multiphase polymeric composites: review on their properties and applications. J Mater Sci2020; 55: 2682–2724. https://doi.org/10.1007/s10853-019-04196-y
38.
YanLZhouYZhangX, et al.Effect of graphene oxide with different exfoliation levels on the mechanical properties of epoxy nanocomposites. Polym Bull2019; 76: 6033–6047. https://doi.org/10.1007/s00289-018-02675-x
39.
YaoYFanZSangM, et al.Anti-impact composite based on shear stiffening gel: structural design and multifunctional applications. Giant2024; 18: 100285. https://doi.org/10.1016/j.giant.2024.100285
40.
NwosuCNIliutMVijayaraghavanA. Graphene and water-based elastomer nanocomposites – a review. Nanoscale nanocomposites – a review2021; 13: 9505–9540. https://doi.org/10.1039/d1nr01324f
41.
MonteserínCBlancoMAranzabeE, et al. Effects of graphene oxide and chemically-reduced graphene oxide on the dynamic mechanical properties of epoxy amine composites. Polymers (Basel); 9(9): 449. https://doi.org/10.3390/polym9090449
42.
GargABasuSMahajanRL, et al.Enhancement in mechanical properties of GFRP-coal-derived graphene oxide composites by addition of multiwalled carbon nanotubes and halloysite nanotubes: a comparative study. Polym Compos2024; 45(14): 13164–13179. https://doi.org/10.1002/pc.28694, Epub ahead of print 10.
43.
BlantonTNMajumdarD. X-ray diffraction characterization of polymer intercalated graphite oxide. In: Powder Diffraction, 2012, pp. 104–107.
44.
RafieeMARafieeJWangZ, et al.Enhanced mechanical properties of nanocomposites at low graphene content. ACS Nano2009; 3: 3884–3890. https://doi.org/10.1021/nn9010472
45.
ZeinediniA.Fracture toughness of graphene/polymer nanocomposites: well dispersion, agglomeration and toughening mechanisms. Theor Appl Fract Mech; 131(24): 104449. https://doi.org/10.1016/j.tafmec.2024.104449
46.
EqraRMoghimMHEqraN. A study on the mechanical properties of graphene oxide/epoxy nanocomposites. Polym Polym Compos2021; 29: S556–S564. https://doi.org/10.1177/09673911211011150
47.
YangGMaYLiuC, et al.Enhance the mechanical properties of epoxy resin reinforced with functionalized graphene oxide nanocomposites prepared by atom transfer radical polymerization. Polym Compos2022; 43: 7130–7142. https://doi.org/10.1002/pc.26776
48.
YaoSSMaCLJinFL, et al.Fracture toughness enhancement of epoxy resin reinforced with graphene nanoplatelets and carbon nanotubes. Kor J Chem Eng2020; 37: 2075–2083. https://doi.org/10.1007/s11814-020-0620-4
PokharelPTruongQTLeeDS. Multi-step microwave reduction of graphite oxide and its use in the formation of electrically conductive graphene/epoxy composites. Compos B Eng2014; 64: 187–193. https://doi.org/10.1016/j.compositesb.2014.04.013
