Effects of polyvinylpyrrolidone as a dispersant agent of reduced graphene oxide on the properties of carbon fiber-reinforced polymer composites

Abstract

The electrical and mechanical properties of carbon fiber-reinforced polymer (CFRP) composites have a close dependence on the use of modifiers like polyvinylpyrrolidone (PVP), as well as on the processing techniques to disperse functional charges such as graphene-related materials into the epoxy base. In the present work, reduced graphene oxide (RGO), prepared by a natural antioxidant agent, astaxanthin, was used as a filler material in the epoxy matrix of the carbon fiber composites. The astaxanthin reduction leads to an increase in the sp2 ordering in RGO; some residual epoxy and C-O groups that enhance the interaction with the epoxy matrix remain after reduction. The effects of RGO and PVP-modified RGO (PVP-RGO) fillers with different contents (0.05, 0.1, and 0.15% wt.) on the electrical conductivity, bending properties, and dynamic mechanical properties of CFRP were investigated. The incorporation of 0.15 wt.% RGO with and without PVP-modification, leads to through-the-thickness (Z-direction testing) conductivity values 7.4 and 9.6 times higher than those of the neat composite, respectively. The conductivity tests indicate that the RGO/epoxy composite behaves as a continuous conductor due to the formation of agglomerates of RGO within the matrix, while at the added contents of the PVP-RGO filler, the composite is below the percolation threshold, then conducting by electron tunneling, due to a better dispersion of the PVP-RGO filler within the epoxy matrix. The dynamic mechanical analysis shows that the glass transition temperature is indicative of the interactions among the filler, the epoxy matrix, and the carbon fiber, that is, the PVP-RGO filler increases the chain mobility due to its higher dispersion in the matrix. While Tg of the neat epoxy/CFRP composite is 92.5°C, a minimum Tg of 88.5°C was achieved with a 0.10 % wt. PVP-RGO filler contents, and a maximum Tg of 94.5°C with a 0.15 % wt. of RGO filler amount. For constant filler content (0.15 wt.%), CFRP composite containing RGO and PVP-modified RGO exhibited 9.73% and 13.87% increase in flexural strength values, respectively, compared to the neat composite. The bending test revealed that PVP modification to RGO is beneficial to improve flexural strength of CFRP composites.

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“…By properly adapting the imaginary line between the glass transition temperature towards left and extending the same towards right up to decomposition temperature, it would be easy to calculate the reactions. Likewise, the degree of cross‐linking may be easily determined by using specific heat of reaction which was provided by data provided by suppliers and consecutively supported by many authors 37 . Alternatively, the specific decomposition heat of the reaction could be determined through the DSC curves as well as weight loss from the sample.…”

“…As such values observed in the tensile strength, and flexural strength also showed a hike in the values up to the addition of 5% of particulates. Whereas a hike in the temperature predominately induces the nucleation in the matrix and lessens the interfacial adhesion between the particulate, matrix, and fiber surfaces, this was the reason why the laminate breaks early as compared with the dry specimens 37 . The water penetrates deep into the interface because of the temperature and rushes toward the microvoids and micro‐cracks, simultaneously trapped across the laminate inner surface as well in the interface region.…”

International research in graphene-oxide based materials for net-zero energy, military and aeronautic applications catalysed by Tamaulipas, Mexico: a mini review

“…Significant improvements were achieved in the electrical conductivity and flexural strength of CFRP containing reduced graphene oxide dispersed with polyvinylpyrrolidone. Maximum strength (550 ± 43 MPa) and ductility (2.65% ± 0.21%) were obtained for 0.15 wt% rGO/epoxy CF composites with PVP modification (Kaftelen-Odabaşı et al, 2022). Moreover, PVPmodified rGO composites showed approximately 27 and 36-times improvement in surface and T-T-T electrical conductivity, respectively, compared to those without graphene filler (Kaftelen-Odabaşı et al, 2022).…”

“…This will cause interfacial interactions between the carbon filler and the matrix in the composites which results in poor reinforcement effect and shielding efficiency. The uniform dispersion of graphene nanoparticles in the epoxy matrix without aggregation and an optimized dispersion can be achieved by overcoming the Van der Waals forces that hinder the dispersion of graphene by covalent and non-covalent modifications (Kaftelen-Odabaşı et al, 2022;Kaftelen-Odabaşı et al, 2023). Significant improvements were achieved in the electrical conductivity and flexural strength of CFRP containing reduced graphene oxide dispersed with polyvinylpyrrolidone.…”

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“…Fiber-reinforced polymeric composites (FRPs), a typical lightweight engineering material with remarkable specific modulus and strength, heat insulation, corrosion resistance and shock absorption are increasingly favored in diversified fields, such as aerospace, civil engineering and automobile manufacturing [5,6] . Recently, graphene has been envisioned as the powerful building block for next-generation FRPs with the purpose of smart structures integration and multifunctional properties mastery [7,8] . Nevertheless, limited by the technical features of traditional graphene synthesis methods, currently adopted integrated strategies between graphene and FRPs expose significant weaknesses of sophisticated and timeconsuming operation, monotonous function and limited precision, drastically altering the inherent structure and performance of composites, etc.…”