Effect of UV Radiation on Surface Mechanical Properties of NanoTiO2–Acrylic Urethane Coatings

Ching Hsuan Chang, Pu Jui Su, Bernard H. Liu, Stephanie S. Watson, Lipiin Sung

Research output: Chapter in Book/Report/Conference proceedingChapter

1 Citation (Scopus)


Nanoindentation was used to monitor the changes in surface mechanical property of nanotitanium dioxide (nanoTiO2)/acrylic urethane (AU) coatings exposed to high-intensity UV radiation at 55°C and dry conditions. Five TiO2 nanoparticles of similar size but different crystal phases and surface treatments were selected in this study. Preliminary results indicate that two competing behaviors (hardening vs. softening) were found in surface modulus and hardness changes, as UV exposure time was increased. The relationship between photodegradation-induced surface mechanical behavior and the characteristics of nanoTiO2 (crystal phases and surface treatments) was examined. It appears that AU coatings containing rutile nanoTiO2, regardless of surface treatment, exhibit the typical hardening behavior. However, the AU coatings containing anatase or anatase/rutile mix (high anatase ratio) nanoTiO2 show a softening behavior. It implies that photoreactivity of nanoTiO2 plays a major role in the photodegradation-induced surface mechanical behavior. Other key physical parameters, such as surface morphology and filler dispersion measured using laser scanning confocal microscope, and bulk mechanical properties measured by tensile testing were obtained. The correlation between these physical quantities and the surface mechanical properties may provide a fundamental understanding of the photodegradation-induced surface mechanical behavior for different nanoTiO2/AU coatings.

Original languageEnglish
Title of host publicationService Life Prediction of Polymers and Plastics Exposed to Outdoor Weathering
Number of pages16
ISBN (Electronic)9780323497763
ISBN (Print)9780323497770
Publication statusPublished - 2017 Jan 1

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Materials Science(all)


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