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.