Fabrication and mechanical properties of clay/epoxy nanocomposite and its polymer concrete

In this research, the effects of adding modified nanoclay (Cloisite 30B) on the mechanical properties (tensile, compression, flexural and fracture toughness) of epoxy polymer (ML-506) were investigated. Subsequently, the mechanical properties of polymer concrete (PC) made of nanoclay/epoxy were also studied. The nanoclay dispersion was achieved by sonication technique. Therefore, optimum sonication output power and time for achieving the highest d-spacing of nanoclay layers were obtained. The X-ray diffraction (XRD) results indicated that changing sonication output power and time during fabrication process did not have any remarkable effects on increasing the d-spacing of clay layers. In all production processes, the d-spacing was increased from 18.4Å to about 42Å and thus the intercalated nanocomposites were fabricated. In addition to XRD, the dispersion state and the d-spacing of nanoclay particles were observed using a transmission electron microscope (TEM). Also, the effects of various filler contents on the mechanical properties, i.e., tensile, compression, flexural and fracture toughness of nanocomposite were investigated. The results of mechanical testing showed that enhancement in the tensile and flexural moduli, compressive strength and fracture toughness were gained by 12.5%, 13.3%, 7.4% and 25.5% respectively. On the other hand, tensile and flexural strengths as well as strain to failure were decreased. Scanning electron microscope (SEM) was also used to study the fracture mechanism of nanocomposites. Finally, by adding the optimum amounts of nanoclay to the PC, its mechanical properties were compared with conventional ones. The results indicated that introduction of nanoclay into the PC did not improve tensile and flexural strengths although compression strength and fracture toughness were enhanced by 15.2% and 7.6% respectively.

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► Obtaining optimum sonication power and time to fabricate clay/epoxy nanocomposites.
► Improving the tensile and flexural moduli of clay/epoxy nanocomposites.
► Increasing the fracture toughness and compressive strength of nanocomposites.
► Nanoclay enhanced the tensile and compressive strengths of polymer concrete.
► Improving the fracture toughness of polymer concrete by addition of nanoclay.