Improving the Performance of Vegetable Oil-based Epoxies for Coating and Composite Applications

Abstract: Use of vegetable oil (VO)-derived compounds for preparation of alternative thermosetting polymers has received extensive investigation, in part due to the relative simplicity of chemical conversion and the liquid form of the products. Some VO-based polyurethanes and unsaturated polyesters demonstrate certain promise in the niche market. However, the strength, stiffness and heat resistance of VO-based thermosets are inadequate for some other applications, especially when attempted for substitution of epoxies.  This is because VO-derived monomers are built on the triglyceride structure in which the polymerizable groups are generally separated in space by long flexible fatty chains. 

In this work, we introduce the measures to improve the mechanical and thermal properties of VO-based epoxies, including shortening of the spacer length between epoxy groups, use of rigid comonomers and curing with rigid hardeners. In addition, dynamic covalent chemistry is employed in the design of VO-based epoxies so that the resulting resin systems exhibit improved chemical recyclability and a certain degree of self-repairing property that is attainable to conventional epoxies. These improvements enable VO-based epoxies to substitute their traditional counterparts in coating and composite applications.