Synthesis of High Mechanical Strength and Thermally Recyclable and Reversible Polyurethane Adhesive by Diels-Alder Reaction

Recyclability of polyurethane materials is significant to relieve environmental problems caused by damaged polymers. Inspired by plenty of self-healing properties based on dynamic covalent bonds. A high mechanical strength and thermally reversible polyurethane adhesive are acquired through co-polymerization of poly-1,4-butylene adipate glycol (PBA), soybean oil-based polyol (MESO), and toluene diisocyanate (TDI) whose linear polymer chains are constructed by Diels-Alder reaction between furfuryl alcohol (FA) and bismaleimide (BMI), named DAPU. Further, the obtained polyurethane adhesives show great recyclability, mechanical performance (Whose tensile strength can reach 91.7 MPa), and appropriate self-healing ability through the thermally reversible Diels-Alder covalent bonds and hydrogen bonds between urethane groups, which may pave a way for further development of recyclable materials. In order to cope with the emergence of microcracks in materials and extend the service life of materials, by introducing dynamic covalent bonds as Diels-Alder bonds into traditional polymer materials, a strong, thermally recyclable, and reversible polyurethane adhesive is designed and synthesized. As a result, the tensile strength of DAPU-10 could reach 91 91 MPa and the DAPU shows thermal stimulus properties and appropriate self-healing function. image