Polybutadiene derived allophanate as the crosslinker for Diels–Alder type self‐healing polyurethane networks

Abstract

Intrinsic self‐healing materials have drawn great interest in recent years. The design of novel building blocks is essential for developing polymer networks with different properties. Allophanate is usually regarded as a side product during the preparation of polyurethanes. During the research of self‐healing polyurethane networks, we have studied the terminal functionalization of hydroxyl‐terminated polybutadiene with furfuryl isocyanate and occasionally obtained the furan‐terminated polybutadiene allophanate. The tetra‐branched molecule is employed as the crosslinker in the construction of a series of Diels–Alder type polyurethane networks. These polyurethane networks exhibit good mechanical performance and excellent self‐healing ability. Damages can be healed via the thermo‐promoted dissociation and recombination cycle, giving good to excellent recovery of tensile strength within three cycles of “damage‐repair” processes.

Molecularly Engineered Tough and Room-Temperature Self-Healing Polyurethanes for Resistive Strain Sensors

“…Due to the limited thermodynamic compatibility between its soft and hard segments, TPU exhibits a microphase-separated structure, which imparts superior toughness and elasticity to the material. − By changing the structures of the soft and hard segments or chain extenders, the performance of TPU can be tailored over a wide range . In recent years, researchers have achieved a self-healing effect by incorporating dynamic covalent or noncovalent bonds into the molecular structure of TPU, such as Diels–Alder bond, , imine bond, , boronate ester bond, oxime bond, disulfide bond, , metal ion coordination bond, hydrogen bond, − and so on. These dynamic bonds endow TPU with self-healing performance under external stimuli.…”