A Review on Graphene's Light Stabilizing Effects for Reduced Photodegradation of Polymers

Graphene, the newest member of the carbon's family, has proven its efficiency in improving polymers' resistance against photodegradation, even at low loadings equal to 1 wt% or lower. This protective role involves a multitude of complementary mechanisms associated with graphene's unique geometry and chemistry. In this review, these mechanisms, taking place during both the initiation and propagation steps of photodegradation, are discussed concerning graphene and graphene derivatives, i.e., graphene oxide (GO) and reduced graphene oxide (rGO). In particular, graphene displays important UV absorption, free radical scavenging, and quenching capabilities thanks to the abundant pi-bonds and sp(2) carbon sites in its hexagonal lattice structure. The free radical scavenging effect is also partially linked with functional hydroxyl groups on the surface. However, the sp(2) sites remain the predominant player, which makes graphene's antioxidant effect potentially stronger than rGO and GO. Besides, UV screening and oxygen barriers are active protective mechanisms attributed to graphene's high surface area and 2D geometry. Moreover, the way that graphene, as a nucleating agent, can improve the photostability of polymers, have been explored as well. These include the potential effect of graphene on increasing polymer's glass transition temperature and crystallinity.

Automated summary

Graphene has been proven to be highly efficient in improving the resistance of polymers against photodegradation, mainly due to its unique geometry and chemistry. This protective role involves mechanisms such as UV absorption, free radical scavenging, and quenching, making graphene potentially stronger in antioxidant effect compared to rGO and GO. Additionally, graphene's high surface area and 2D geometry contribute to UV screening and oxygen barriers, enhancing its protective capabilities.