Mechanical and electrochemical properties of UV-curable nanocellulose/urushiol epoxy acrylate anti-corrosive composite coatings

A novel urushiol epoxy acrylate (UEA) photosensitive prepolymer was synthesized. In order to realize the curing of UEA, modified cellulose nanofiber photoinitiators (MCNFI) were prepared through the modification of cellulose nanofiber (CNF). Then UV-curable MCNFI/UEA composite coatings were fabricated, and their structures, mechanical and electrochemical properties were investigated. The results showed that the studied properties of MCNFI/UEA coating were superior to those of pure UEA and unmodified CNF reinforced UEA (CNF/UEA) coating. The optimum mechanical properties were achieved at 8 wt% loading level, after which further loading of MCNFI resulted in the reduction in mechanical properties. The enhanced mechanical properties should be attributed to the structural characteristics of UEA matrix containing appropriate soft and hard segments, the good dispersibility and interfacial interaction of the fillers within UEA matrix. Besides, MCNFI (8 wt%)/UEA coating exhibited the most pronounced anti-corrosive performance. This paper demonstrated a novel preparation method of renewable urushiol based anti-corrosive coating using modified nanocellulose as macrophotoinitiator and filler simultaneously.