Gamma radiolysis of a heavy petroleum fraction

A relatively heavy petroleum fraction called distillate aromatic extract (DAE) which has been proposed to be the carrier of the emission bands of certain astronomical objects like protoplanetary nebulae (PPNe) and the so-called unidentified infrared bands (UL1Bs), has been radiolyzed with gamma-radiation to a total dose of I MGy. The stability of DAE toward radiation was assessed by FT-IR and electronic spectroscopy. The gases produced during radiolysis have been identified by GC. They were essentially H-2 and CH4. A certain degree of crosslinking has been verified on the radiation-processed material by measuring the hexane insoluble fraction of DAE, which increased dramatically after the radiation treatment. Further analyses were conducted using high performance liquid chromatography (HPLC) on the radiation processed sample in comparison to the pristine sample.