Down-cycling flexible polyurethane foam (FPUF) waste into asphalt addresses the current shortage of effective, economic, and eco-friendly anti-aging additives and polymer disposal difficulty. In this study, anti-aging performance-oriented modification was carried out by selectively pyrolyzing and down-cycling waste FPUF. To begin with, a sustainable anti-aging fiber modifier was proposed by depolymerizing hard segments in FPUF in the temperature range of 260–320 °C. Subsequently, The chemical, morphological, and rheological properties of pyrolyzed FPUF fiber modified asphalt (PyFMA) were evaluated to clarify anti-aging mechanisms, anti-aging behaviors, and relative competitiveness. The results showed that the proposed selective pyrolysis method was able to efficiently and conveniently produce FPUF fiber in certain temperature and duration ranges. The anti-aging enhancement of PyFMA was the result of a combination of antioxidant exchange, physical isolation, and chemical protection. Fiber dosage of FPUF played a dominant role in improving the anti-aging resistance as well as the high-temperature performance and fatigue resistance of asphalt. Quantification of anti-aging enhancement and performance improvement indicated that the FPUF fiber has competitive compared to existing synthetic, natural, and recycled additives. PyFMA composed of binder B and 24 wt% F3-T1 fiber showed the most balanced and superior performance in terms of growth ratio. In summary, the findings are beneficial for effectively and economically improving the aging resistance of asphalt and addressing the disposal difficulty of FPUF waste.

中文翻译：

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热解软质聚氨酯泡沫沥青结合料的抗氧化性能改进


将软质聚氨酯泡沫（FPUF）废物降级回收为沥青，解决了目前有效、经济、环保的抗老化添加剂的短缺和聚合物处理困难的问题。本研究通过对废弃FPUF进行选择性热解和降级循环，进行抗老化性能导向的改性。首先，通过在 260–320 °C 的温度范围内解聚 FPUF 中的硬链段，提出了一种可持续的抗老化纤维改性剂。随后，对热解 FPUF 纤维改性沥青（PyFMA）的化学、形态和流变性能进行了评估，以阐明其抗老化机制、抗老化行为和相对竞争力。结果表明，所提出的选择性热解方法能够在一定的温度和持续时间范围内高效、便捷地生产FPUF纤维。 PyFMA 的抗衰老增强作用是抗氧化剂交换、物理隔离和化学保护相结合的结果。 FPUF的纤维掺量对提高沥青的抗老化性能、高温性能和抗疲劳性能起到了主导作用。抗老化增强和性能改进的量化表明，与现有的合成、天然和回收添加剂相比，FPUF 纤维具有竞争力。由粘合剂 B 和 24 wt% F3-T1 纤维组成的 PyFMA 在生长率方面表现出最平衡和优越的性能。综上所述，该研究结果有利于有效、经济地提高沥青的抗老化性能，解决FPUF废弃物的处理难题。