Behaviour of carbon black pigments as excited state quenchers in LDPE

A total of eight different carbon black pigments have been incorporated into low density polyethylene at 0.2% w/w concentration and their ability to operate as effective singlet and triplet quenchers examined using luminescence analysis. All pigments effectively reduced the fluorescence and phosphorescence emission intensities. A large variability was observed in the triplet lifetime quenching, the effect varying with the pigment type. Although not consistent throughout, there is some indication that low surface area carbon black pigments can be the most effective quenchers of active excited states. The implications of carbon black pigments to operate as "super quenchers" under practical concentration conditions is discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.