The peroxide degradation of polypropylene was studied in supercritical carbon dioxide in the presence of a coagent. 18 coagents were tested and their results were analysed to gain insight on structure-property relations. Broadly four different categories were identified, where coagents such as toluene do not show much of an effect, molecules such as hydroquinone show a large effect towards suppressing the degradation, and molecules such as phenol are somewhere in the middle. The fourth category was only based on a single molecule, n-hydroxyphthalimide, which was the only molecule to exhibit more degradation than the peroxide would have done alone.
Keywords: Polypropylene, degradation, β-scission, structure-property relations, peroxide, n-hydroxyphtalimide, hydroquinone, benzoquinone, phenol, toluene, supercritical carbon dioxide.