Photoconductivity Technique for the Assessment of Pigment Photoreactivity.
Photoconductivity Technique for the Assessment of
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;
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.