Bio-Based Hyperbranched Toughener From Tannic Acid and Its Enhanced Solvent-Free Epoxy Resin with High Performance

It is essential to design economic and efficient tougheners to prepare high-performance epoxy resin; however, this has remained a huge challenge. Herein, an eco-friendly, low-cost, and facile-fabricated bio-based hyperbranched toughener, carboxylic acid-functionalized tannic acid (CATA), was successfully prepared and applicated to the preparation of solvent-free epoxy resins. The mechanical performance, morphology, structural characterization, and thermal characterization of toughened epoxy resin system were studied. The toughened epoxy resin system with only 1.0wt% CATA reached the highest impact strength, 111% higher than the neat epoxy resin system. Notably, the tensile strength and elongation at break of toughened epoxy resin systems increased moderately with increasing CATA loading. Nonphase-separated hybrids with significant toughening effect were obtained. Additionally, the thermal stabilities of toughened epoxy resin systems decreased with increasing CATA loading. This study provides an eco-friendly, cost-effective, and facile approach for the preparation of high-performance, solvent-free epoxy resins with potential for practical applications in sealing integrated circuits and electrical devices fields.