Self-healing polyurethanes (PUs) were synthesized as a matrix of nanocomposites containing two fibrous carbon components, i.e., functionalized carbon nanotubes (CNF-OH) and short carbon fibers (CF). Two types of PUs differing in the content of flexible chain segments (40% and 50%) were used. Changes in mechanical strength were analyzed to assess the ability to self-healing of PU-based matrix nanocomposites with experimentally introduced damage in the form of an incision. The healing process was activated by heating the damaged samples at 60°C, for 30 minutes. The addition of CNT-OH and CF caused a slight reduction in the self-healing ability of the nanocomposites as compared to the neat PUs. After heating to 60°C, the nanocomposites self-healed up to 72% of the initial strength of the undamaged samples. The introduction of fibrous components to the polymer matrix improved the thermal conductivity of nanocomposites and facilitated heat transfer from the environment to the interior of the samples, necessary to initiate self-healing. Low content of carbon components in the PU matrix, i.e., 3 wt% of CF and 2 wt% of CNF-OH increased the total work up to fracture of samples after healing by about 53%.

中文翻译：

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碳纤维和碳纳米管改性的自修复聚氨酯基纳米复合材料

自修复聚氨酯 (PU) 被合成为包含两种纤维碳成分的纳米复合材料的基质，即功能化碳纳米管 (CNF-OH) 和短碳纤维 (CF)。使用了两种类型的 PU，其柔性链段的含量不同（40% 和 50%）。分析了机械强度的变化，以评估基于 PU 的基质纳米复合材料的自愈能力，并通过实验引入切口形式的损伤。通过在 60°C 下加热受损样品 30 分钟来激活愈合过程。与纯 PU 相比，CNT-OH 和 CF 的添加导致纳米复合材料的自修复能力略有降低。加热至 60°C 后，纳米复合材料的自愈能力高达未损坏样品初始强度的 72%。向聚合物基质中引入纤维成分提高了纳米复合材料的导热性，并促进了从环境到样品内部的热传递，这是启动自愈所必需的。PU 基质中碳成分的含量低，即 3 wt% 的 CF 和 2 wt% 的 CNF-OH 使愈合后样品断裂的总功增加了约 53%。