Analysis of polymer oxidation using 18O2 and TOF-SIMS

Abstract We have investigated oxidative degradation of low density polyethylene (LDPE) by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Replacing 16 O 2 in the exposure atmosphere by 18 O 2 makes it possible to identify species originating from the artificial ageing, since oxygen present in the material prior to ageing can then be distinguished from oxygen introduced in the ageing process. The yield of O-ions in TOF-SIMS is very high, making oxygen-18 an excellent tool for following early stages of oxidative degradation. Furthermore, we have identified two 18 O-containing ions, CH 3 18 O + and C 2 H 3 18 O + , which can also be used to follow the oxidation processes.