Abstract

The loading and morphology of zinc oxide (ZnO) affect the bonding and segmentation in commercial polyurethane (PU) coatings. By virtue of surface modification, hexagonal ZnO microprisms can be uniformly dispersed in PU matrix even at a loading as high as 25 wt%. However, the disruption of ZnO fillers can be observed with the suppression of characteristic PU absorption bands in Fourier transform infrared (FT-IR) spectra and the enthalpy reduction in differential scanning calorimetry (DSC) thermograms. The morphological effect is highlighted by the significant changes in DSC and FT-IR spectra when hexagonal ZnO is substituted with the sword-like counterpart. The results suggest that more sword-like ZnO can be loaded in PU coatings with a less disruption in bonding and segmentation.