Organoclay effect on mechanical responses of glass/epoxy nanocomposites

Abstract

This research aims to perform a symmetric investigation regarding the organoclay effect on the mechanical behaviors of glass/epoxy nanocomposites. Tensile, flexural, as well as interlaminar fracture toughness are of concern in this study. To demonstrate the organoclay effect, three different loadings, 2.5, 5 and 7.5 wt% of organoclay were dispersed in the epoxy resin using a mechanical mixer followed by sonication. The corresponding glass/epoxy nanocomposites were prepared by inserting the organoclay epoxy mixture into the dry glass fiber through a vacuum hand lay-up process. Tensile tests revealed that longitudinal tensile strength decreases as organoclay loading increases; on the other hand, transverse tensile strength increases with the increase of the organoclay. Furthermore, SEM observation on the transverse failure specimens indicates that the enhanced mechanism is due to the improved interfacial bonding between the fibers and the surrounding matrix modified by organoclay. The increasing tendency was also found in the transverse flexural strength of the nanocomposites. However, mode I fracture tests indicated that with the increase of the organoclay, the corresponding fracture toughness of the nanocomposites decreases appreciably. For the quasi-isotropic glass/epoxy laminates, since the failure is dominated by fiber rupture, the strength is not influenced significantly by the organoclay.