Rosin-Based Epoxy Vitrimers with Dynamic Boronic Ester Bonds

Rosin is an abundantly available natural product. In this paper, for the first time, a rosin derivative is employed as the main monomer for preparation of epoxy vitrimers to improve the mechanical properties of vitrimers. Novel epoxy vitrimer networks with dynamic reversible covalent boronic ester bonds are constructed by a reaction between thiols in 2,2′–(1,4–phenylene)–bis (4–mercaptan–1,3,2–dioxaborolane) (BDB) as a curing agent and epoxy groups in the rosin derivative. The rosin-based epoxy vitrimer networks are fully characterized by Fourier transform infrared spectroscopy (FTIR), an equilibrium swelling experiment, and dynamic mechanical analysis (DMA). The obtained rosin-based epoxy vitrimers possess superior thermostability and good mechanical properties. Due to transesterification of boronic ester bonds, rosin epoxy vitrimer network topologies can be altered, giving welding, recycle, self-healing, and shape memory abilities to the fabricated polymer. Besides, the effects of treating time and temperature on welding capability is investigated, and it is found that the welding efficiency of the 20% C-FPAE sample is >93% after treatment for 12 h at 160 °C. Moreover, through a hot press, the pulverized samples of 20% C-FPAE can be reshaped several times and most mechanical properties are restored after reprocessing at 200 °C for 60 min. Finally, chemical degradation is researched for the rosin-based epoxy vitrimers.