The role of surface modified TiO2 nanoparticles on the mechanical and thermal properties of CTBN toughened epoxy nanocomposite

Abstract

The primary objective of this study was to investigate the role of surface modified TiO2 nanoparticles on the mechanical and thermal properties of rubber toughened epoxy nanocomposite. TiO2 nanoparticles were surface modified using 11-aminoundecyltriethoxysilane (TiO2-AUTES) and n-octyltriethoxysilane (TiO2-OTES) and the successful functionalization of nanoparticles was established by performing FTIR, contact angle, and TGA measurements. The graft density of silane groups on TiO2 nanoparticles was established to be 13.7 % for TiO2-AUTES and 11.4 % for TiO2-OTES. Functionalized TiO2 (fTiO2) was mixed with carboxyl-terminated butadiene (CTBN) toughened epoxy by ultrasonication followed by the addition of curing agent, and the overall mixture was blended with planetary shear mixer. The loss in the modulus of epoxy due to addition of rubber toughener was offset by the addition of nanoparticles. One of the significant findings of the work was the observed trend in the fracture energy of the samples: fTiO2 filled CTBN toughened epoxy >TiO2 filled CTBN toughened epoxy >TiO2 filled epoxy >CTBN toughened epoxy >epoxy resin. The findings of our work show promise for use of TiO2 nanoparticles in conjunction with CTBN toughener as fillers for improving the toughness of epoxy resin without comprising the tensile strength of advanced structural materials.