▎ 摘　　要

The unique sp(2)-bonded structure of graphene sheets not only enables many functional applications but also endows graphene with an attractive free radical scavenging activity to prevent the thermo-oxidative degradation of polymers. In this study, the effect of thermal reduction temperature (Tr) on the structural evolution and free radical scavenging capacity of thermally reduced graphene oxide (TRGO) is explored within 200-1000 degrees C. The completeness and size of sp(2) hybrid domains, which can be tailored by changing the thermal reduction temperature, are suggested to be key factors determining the free radical scavenging activity of TRGO. As the Tr increases from 200 to 800 degrees C, the stabilization ability of TRGO against the thermo-oxidative degradation of isotactic polypropylene is enhanced gradually because of the removal of oxygen-containing functional groups and the restoration of sp(2) hybrid domains. However, further elevating Tr to higher temperatures such as 1000 degrees C will lead to the formation of a large number of hole defects on the TRGO platelets, possibly because of the removal of lots of oxygen-containing functional groups and the destruction of their ordered structure.