Analysis of polymer oxidation using ~(18)O_2 and TOF-SIMS

摘要

We have investigated oxidative degradation of low density polyethylene (LDPE) by time-of-flight secondary ion mass spectro-metry (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_2H_3~(18)O~+, which can also be used to follow the oxidation processes.