Developing Reassembleable Synthetic Adhesives Based on Epoxidized Soybean Oil and Dynamic Diels-Alder Bonds

Synthetic adhesives rely on interfacial interactions to hold together solid materials. While widely used, their limited reassembleability restricts their applications. This study aims to develop a reassembleable synthetic adhesive with high bonding strength by incorporating dynamic covalent bonds into the adhesive network.

Epoxidized soybean oil (ESO) was chosen as the adhesive substrate, and Diels-Alder bonds were introduced to enable reassembleability. The successful synthesis of the adhesive was confirmed by DSC, UV-Vis spectroscopy, and 1H NMR analysis. The mechanical properties of the adhesive were regulated by adjusting the cross-linker quantity, with higher amounts leading to increased stress at break and toughness. The adhesive also exhibited self-healing properties, with cracks gradually diminishing upon heating. Additionally, the adhesive demonstrated the ability to undergo recycling, with the properties of the recycled adhesive remaining constant.

The adhesive exhibited hydrophilicity due to the presence of polar groups, and its viscosity decreased rapidly during reassembly, facilitating the reassemble process. These findings demonstrate the potential of incorporating dynamic covalent bonds into synthetic adhesives to achieve high bonding strength and reassemble ability. This research contributes to the development of sustainable and intelligent materials with improved performance and recyclability.