Urtica dioica extract as a facile green reductant of graphene oxide for UV resistant and corrosion protective polyurethane coating fabrication

Abstract

Reduction of graphene oxide still is one of discussion subjects in scientific communities. The use of toxic chemicals like hydrazine is a well-known procedure for graphene oxide reduction. In this paper, a new ecofriendly, fully scalable, and cheap approach with easy procedure on industrial scale for producing reduced graphene oxide is introduced. The studied method was based on successful reduction of graphene oxide by urtica dioica leaves’ extract in 1 h at 90 °C. Raman spectroscopy evidenced the significant removal of considerable oxygen functional groups in graphene oxide after reduction. Improving corrosion properties by helping the functionalization ability of u. dioica leaves’ extract for superior dispersion in polyurethane coatings was studied as well. Electrochemical impedance spectroscopy measurements along with salt spray exposure test revealed the remarkable role of resultant reduced graphene oxide in protective function of polyurethane coatings before and after accelerated weathering condition. Impedance value in low frequency diagrams reveals more than 99% protection efficiency indicating the great role of u. dioica in barrier property of PU coatings after accelerated weathering condition.