Preparation of TiO2/epoxy nanocomposites by ultrasonic dispersion and their structure property relationship

By the insertion of nanoparticles into a polymer matrix a considerable improvement of mechanical properties can be achieved. Therefore, a homogeneous distribution of fillers within the matrix is required. In the present paper the dispersion of TiO2-nanoparticles in a DGEBA (diglycidyl ether of bisphenol A) epoxy resin by means of an ultrasonic horn was studied. The systematic examination of process parameters of a previous study was completed in order to determine the optimum processing window leading to a good dispersion result without degrading the molecular structure of the epoxy resin. Therefore, particle sizes were examined using a dynamic light scattering device, and the effect of the ultrasonic treatment on the resin was surveyed by FT-IR spectroscopy (Fourier transform infrared spectroscopy). Furthermore, the mechanical performance of the nanocomposites was examined for various contents of TiO2-nanoparticles to show that the materials prepared by ultrasonic dispersion show an improved property's profile. In order to understand the reinforcing mechanisms of nanoparticles in the polymer matrix providing improved mechanical properties, scanning electron microscope (SEM) pictures of the fracture surfaces of the samples were carried out, which revealed that nanocomposites show a significantly rougher surface than the neat epoxy resin. This indicates a change in the fracture mechanisms. (C) 2010 Elsevier B.V. All rights reserved.