Furthermore, this packaging has been shown to have both antibacterial and photocatalytic activity, the latter of which reduces ultraviolet (UV) exposure (5Trusted Source, 6).
THE OBSCURE HISTORY OF A UBIQUITOUS PIGMENT: PHOSPHORESCENT LITHOPONE AND ITS APPEARANCE ON DRAWINGS BY JOHN LA FARGE
Although barium sulfate is almost completely inert, zinc sulfide degrades upon exposure to UV light, leading to darkening of the pigment. The severity of this UV reaction is dependent on a combination of two factors; how much zinc sulfide makes up the pigments formulation, and its total accumulated UV exposure. Depending on these factors the pigment itself can vary in shade over time, ranging from pure white all the way to grey or even black. To suppress this effect, a dopant may be used, such as a small amount of cobalt salts, which would be added to the formulation. This process creates cobalt-doped zinc sulfide. The cobalt salts help to stabilize zinc sulfide so it will not have as severe a reaction to UV exposure.
They must adhere to stringent production standards to guarantee the purity and performance characteristics required by diverse applications They must adhere to stringent production standards to guarantee the purity and performance characteristics required by diverse applications30-50nm tio2 powders supplier.