Wide-temperature range damping polyurea-urethane blends with self-healing capability

Damping materials are used in many fields, and damping property within a wide temperature range is usually required. More importantly, the ability for damping materials to recover from damages can prolong the service life. In the present work, we prepared damping materials with loss factor beyond 0.3 within 80 ℃ and self-healing capability based on the gradient phase separated morphologies of epoxy domains in polyurea-urethane matrix. The epoxy oligomer (E) with dangling furan groups can be compatible with polyurea-urethane (U) that consisted of disulfide bonds in the main chains and intermolecular hydrogen bonding, but the reversibly crosslinked epoxy domains based on Diels-Alder reaction phase separated from the matrix. The gradient morphology, thus, was created by controlling the diffusions of 4,4′-methylenebis(N-phenylmaleimide) (B) and epoxy oligomer in the polyurethane matrix using multilayer assembly. The morphologies were determined by the weight ratios of the layers with U + E + B, U + E, and U, respectively. The increase in the ratio of layer U + E + B against layer U + E, more evident gradient morphology was found as well as the mechanical property, anti-solvent resistance, and noise absorption were increased. The loss factor was moved toward high temperature. The increase in the contribution of layer U + E reduced the temperature of the loss factor as well as increased the impact resistance and self-healing capability. The polyurea-urethane blends with gradient phase separated morphologies can be used as good damping materials for noise absorption and impact resistance, while the self-healing capability facilitated the recovery from fatigue, microcracks, or even damage due to frequent energy absorption and dissipation.