(328a) Polymer/titania Composites Produced By Atomic Layer Deposition

Micron-sized HDPE particles are coated with TiO2 films by atomic layer deposition (ALD) in a scalable fluidized bed reactor. The coating experiments are carried out by alternatively exposure to titanium tetraisopropoxide (TTIP) and hydrogen peroxide at the temperature of 77 °C, which is lower than the softening/melting point of the HDPE particles. The coated particles are characterized using Fourier Transform Infrared Spectroscopy, Scanning and Transmission Electron Microscopy, Surface Area, X-Ray Photoelectron Spectroscopy, X-Ray Diffraction and Induced Coupled Plasma-Atomic Emission Spectroscopy. The coated polymer particles are extruded into films by a heated extruder. During the high shear/high stress extrusion process, the shell on the polymer particle surface will crack and the shell remnants will be dispersed homogeneously throughout the polymer matrix. By means of this novel technique, well-dispersed polymer/TiO2 nanocomposites are formed. The photoactivities of TiO2 make this nanocomposites have advanced features, such as self-cleaning and antibacteria. The photoactivities of TiO2 coated HDPE particles and HDPE/TiO2 nanocomposite are tested by measuring the decomposition of methylene blue in its aqueous solution under UV irradiation.