High strength, self-healing, and highly hydrophobic bio-based non-isocyanate polyurethane

Abstract

Non-isocyanate polyurethane (NIPU) has been widely considered for its green production process and sustainable development, and it is expected to be an effective substitute for traditional polyurethane. In this work, biobased five-membered cyclic carbonate was synthesized from trimethylolpropane (TMP) and glycerol (GA) at atmospheric pressure, and then NIPU with high strength, high hydrophobicity, and self-repairing was prepared by reacting cyclic carbonates with polyamines. The three-dimensional cross-linked network structure formed after curing improves the mechanical properties and thermal stability of NIPU, with tensile strengths up to 31.05 MPa. At the same time, benefiting from the dynamic covalent bonding movement and reorganization between urethane and hydroxyl groups, NIPU has a favorable self-repairing function, and the self-repairing efficiency can reach 90 %. The abundance of polar groups provides NIPU with excellent adhesion capabilities and shear strengths up to 4.02 MPa. In addition, the long-chain diamine significantly enhanced NIPU4 hydrophobicity, and the NIPU4–4 coating water contact angle was elevated to 112.65°. This simple and efficient preparation method not only realizes the green preparation of NIPU at atmospheric pressure, but also overcomes the shortcomings of poor hydrophobicity and water resistance on the basis of ensuring good mechanical properties and heat resistance, which provides research ideas for the design and development of bio-based NIPU and expands its applications in building materials, furniture, electronic devices and other industries.