Experimental and modeling approaches for the formation of hydroperoxide during the auto-oxidation of polymers: Thermal-oxidative degradation of polyethylene oxide

Highlights: • Concentration profiles of products and reactant for the thermal oxidation of PEO were determined. • The kinetics of oxidation of PEO were estimated by model fitting to concentration profiles. • A new formation scheme of ROOH via ROO reaction with HO₂ was proposed according to the kinetics data. • The auto-oxidation scheme of polymer was revised. ROOH was a key intermediate compound in oxidation of polymer because it was only source of OH radicals. ROOH was believed to be produced by ROO abstraction H-atom from polymer, which is thermodynamically unfavorable, but it may be facilitated due to the high polymer concentration. However, ROOH also could be produced by ROO reaction with HO₂. For examining the formation scheme of ROOH, kinetics and mechanism for the thermal-oxidative degradation of PEO at 473 K in air was investigated by using the experimental and modeling approaches. The contribution of HO₂ reaction with ROO to the formation of ROOH was estimated.