Evidence of pyrene formation in butadiene–styrene-based rubber subjected to UV irradiation

A strong pyrene emission was observed when certain block, alternate, and random butadiene–styrene-based rubber films were subjected to intense UV irradiation in vacuum. Weak or no pyrene emission was obtained from the same films when they are irradiated in the presence of O2. A mechanistic scheme leading to pyrene formation in these samples is given together with qualitative explanation of the dependence of pyrene formation on sample composition.