Joseph S. Zannucci

Effects of Titanium Dioxide on the Weatherability of Thermoplastic Polymers

Titanium dioxide is used widely as an opacifying agent for paper, fibers, coatings, and plastics. Our data show that this white pigment functions as either a weathering stabilizer or sensitizer, depending on its concentration or treatment during manufacture and use. Lifetimes of oxidizable polymers, such as polypropylene and cellulose esters, can be reduced greatly by the presence of photoactive titanium dioxides; oxidation-resistant polymers, such as poly(tetramethylene terephthalate), are affected to a much lesser extent. The undesirable effects of titanium dioxides can be reduced greatly by the presence of certain additives. The large effects of temperature on the lifetimes of certain polymers indicate that considerable care must be exercised in the design of accelerated test methods.