Dielectric materials with self-healing property after the occurrence of detrimental events such as tearing or scratch are highly desired, which guarantees reliability and lifetime of the electric and electronic systems. Here, a self-healing covalently bonded titanium dioxide/polyurethane (TiO₂/PU) nanocomposite with enhanced dielectric constant was prepared by in-situ polymerization based upon Diels-Alder reaction. The PU prepolymer was prepared from TiO₂, poly(tetramethylene glycol) and 4,4-diphenylmethane diisocyanate. Then the linking between the prepolymer and Diels-Alder adducts of bifunctional maleimide blocked by furfuryl alcohol was carried out. The in-situ polymerization method allows the TiO₂ filler, the PU polymer matrix, and the DA healing portion to be tightly connected, resulting in a stable nanocomposite system. Due to the reversibility of covalent bonds, the TiO₂/PU nanocomposites exhibited thermal self-healing properties after being cut. The dielectric constant and loss, mechanical properties can be effectively restored to their original state after damage.

中文翻译：

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具有可恢复的机械和介电性能的热自修复二氧化钛/聚氨酯纳米复合材料

强烈期望在发生诸如撕裂或刮擦之类的有害事件之后具有自愈特性的介电材料，其保证了电气和电子系统的可靠性和寿命。在此，通过基于Diels-Alder反应的原位聚合制备介电常数提高的自修复共价键合的二氧化钛/聚氨酯（TiO ₂ / PU）纳米复合材料。PU预聚物由TiO ₂，聚（丁二醇）和4，4-二苯基甲烷二异氰酸酯制备。然后进行由糠醇封闭的双官能马来酰亚胺的预聚物和Diels-Alder加合物之间的连接。原位聚合法允许TiO ₂填料，PU聚合物基体和DA愈合部分紧密连接，从而形成稳定的纳米复合材料系统。由于共价键的可逆性，TiO ₂ / PU纳米复合材料在切割后表现出热自修复性能。损坏后，介电常数和损耗，机械性能可以有效地恢复到其原始状态。