Effect of the Mixing Technique of Graphene Nanoplatelets and Graphene Nanofibers on Fracture Toughness of Epoxy Based Nanocomposites and Composites

• Published in: Polymers Vol. 14; no. 23; p. 5105
• Main Authors: Zotti, Aldobenedetto, Zuppolini, Simona, Borriello, Anna, Vinti, Valeria, Trinchillo, Luigi, Borrelli, Domenico, Caraviello, Antonio, Zarrelli, Mauro
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 24-11-2022; MDPI
• Subjects: Analysis; Carbon; carbon fiber reinforced composite (CFRC); Carbon fibers; Dispersion; Epoxy resins; Fiber composites; Fluidized beds; Fracture toughness; Glass transition temperature; Graphene; graphene nanoplatelet (GNP); Graphite; graphite nanofibers; Homogeneity; Mechanical properties; Methods; mode I and mode II interlaminar fracture toughness; Nanocomposites; Nanofibers; Nanomaterials; Nanoparticles; Optical microscopy; Platelets (materials); Polymers; Shear rate; Strain energy release rate; Stress intensity factors; Tensile strength; Thermodynamic properties; United States > US; graphite nanofibers; carbon fiber reinforced composite (CFRC); mode I and mode II interlaminar fracture toughness; fracture toughness; graphene nanoplatelet (GNP); nanocomposites
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym14235105

In this work, the effect of different mixing techniques on thermal and mechanical properties of graphene nanoplatelets (GNPs) and graphene nanofibers (GANFs) loaded epoxy nanocomposites was investigated. Three dispersion methods were employed: a high shear rate (HSR), ultrasonication (US) and the fluidized bed method (FBM). The optical microscopy has revealed that the most suitable dispersion, in terms of homogeneity and cluster size, is achieved by implementing the US and FBM techniques, leading to nanocomposites with the largest increase of glass transition temperature, as supported by the DMA analysis data. The fracture toughness results show a general increase of both the critical stress intensity factor (K
) and the critical strain energy release rate (G
), likely due to the homogeneity and the low scale dispersion of the carbonaceous nanostructures. Based on the nanocomposite fracture toughness improvements and also assuming a potential large scale up production of the nanocomposite matrix, a single mixing technique, namely the FBM, was employed to manufacture the carbon fiber reinforced composite (CFRC). This method has resulted in being less time-consuming and is potentially most suitable for the high volume industrial production. The CFRCs were characterized in terms of tensile, flexural and interlaminar fracture toughness properties and the results were analyzed and discussed.