Design of halloysite modification for improvement of mechanical properties of the epoxy based nanocomposites

Abstract

In this study, halloysite nanotubes (HNT) were modified by: 3-glycidyloxypropyltrimethoxysilane (GLYMO), 3-aminopropyltrimethoxysilane (APTES), and 2,2-Bis[4-(glycidyloxy) phenyl] propane (DGEBA), and incorporated in the epoxy resin matrix to enhance its mechanical properties. The HNT/epoxy nanocomposite materials were prepared by mixing different ratios of untreated/treated HNT with neat epoxy resin. Characterization of untreated/treated HNT was performed by Fourier-transformation infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). The quantity of grafted molecules and thermal stability of newly synthesized materials were determined by thermogravimetric (TG) and derivative thermogravimetric (DTG) analysis. Tensile properties of newly synthesized materials were compared, and scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis of the fracture surfaces were performed. Incorporation of APTES modified HNT (HNTAPT) and two-step modification APTES followed by DGEBA (HNTAPTDG) has increased the tensile strength of the nanocomposite materials up to 72% and 61%, and strain at break up to 1082% and 1216%, respectively, compared to neat epoxy. It was concluded that the modification of HNT contributed to the enhancement of the dispersion and the cross-linking in the epoxy resin matrix.