Influence of surface modification on the dispersion of nanoscale α‐Al2O3 particles in a thermoplastic polyurethane matrix

Abstract

AbstractIn this study, two types of nanoscale α‐Al2O3 particles were used for preparation of α‐Al2O3/thermoplastic polyurethane (TPU) composites. These α‐Al2O3 particles were either coated or uncoated with stearic acid. For the uncoated α‐Al2O3/TPU composite, the results of field‐emission scanning electron microscopy (FE‐SEM) and energy dispersive X‐ray spectrometry indicate that uncoated α‐Al2O3 particles are significantly aggregated together. This aggregation is due to the poor compatibility between the inorganic filler (α‐Al2O3) and the organic matrix (TPU). The size of clusters is in the range from 5 to 20 μm. For the coated α‐Al2O3/TPU composite, FE‐SEM results indicate that most coated α‐Al2O3 particles are well dispersed in the TPU matrix. This phenomenon results from the effect of surface modifier (i.e., stearic acid) on α‐Al2O3 particles. Stearic acid can act as a compatibilizer to bridge the boundary between the TPU matrix and the α‐Al2O3 particle. Stearic acid is not only a suitable surface modifier for the nanoscale α‐Al2O3 particle, but also a good dispersant for the dispersion of nanoscale α‐Al2O3 particles in the TPU matrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008