Behaviour of carbon black pigments as excited state quenchers in LDPE

A total of eight different carbon black pigments have been incorporated int o low density polyethylene at 0.2% w/w concentration and their ability to o perate as effective singlet and triplet quenchers examined using luminescen ce analysis. All pigments effectively reduced the fluorescence and phosphor escence emission intensities. A large variability was observed in the tripl et lifetime quenching, the effect varying with the pigment type. Although n ot consistent throughout, there is some indication that low surface area ca rbon black pigments can be the most effective quenchers of active excited s tates. The implications of carbon black pigments to operate as "super quenc hers" under practical concentration conditions is discussed. (C) 2000 Elsev ier Science Ltd. All rights reserved.