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Photoconductivity Technique for the Assessment of Pigment Photoreactivity.

pdf icon Photoconductivity Technique for the Assessment of Pigment Photoreactivity. (348 K)
Chin, J.; Scierka, S.; Kim, T.; Forster, A.

Federation of Societies for Coatings Technology (FSCT) Technical Program Annual Meeting, 81st. November 12-14, 2003, Philadelphia, PA, Federation of Societies for Coatings Technology, Blue Bell, PA, 2003.


pigment; titanium dioxide; photoreactivity; photoconductivity; UV radiation; coating durability; coatings


Large volumes of titanium dioxide (TiO2) are utilized each year in coatings, sealants, plastics and paper for opacification and pigmentation purposes. It is well known that the photoreactivity of TiO2 can contribute to the degradation of the material that it is dispersed in, due to the generation of electron-hole pairs that further react to form oxidizing and/or reducing agents. A wide range of photoreactivity exists in commercial TiO2 pigments, depending on the manufacturing method used. At the present time, there is no standardized, quantitative measurement technique in the coatings industry for assessing the photoreactivity of pigments. The primary objective of this research is to develop a standardized technique for the measurement of photoreactivity, one with a scientific basis that would provide the most direct correlation to end-use performance. One such technique involves measuring the photoconductivity of the pigments under ultraviolet (UV) irradiation. A prototype photoconductivity testing device and preliminary results from a variety of TiO2 systems will be presented.