| Abstract: | The energy transfer behavior of an ultraviolet stabilizer, nickel dibutyldithiocarbamate (BTN), is examined in solution and in thin polypropylene films. The rate of photosensitized dissociation of this nickel chelate by 4-methyl-2-pentanone in solution was found to be approximately ten times that of its photodissociation after direct ultraviolet excitation. The rate of photodissociation of BTN in preoxidized polypropylene films was also measured. It was found that BTN does not quench the excited carbonyl groups in degassed polymer films. These results are compared to those for nondegassed preoxidized polypropylene samples and are discussed in terms of singlet oxygen quenching. A phenolic antioxidant was found to have no effect on the photodissociation of BTN in either degassed or nondegassed polypropylene films. |
