Yang Haocheng, Cao Suzhou, Wu Chengwei, Xi Zhonghua, Cai Jun, Yuan Zuanru, Zhang Junsheng, Xie Hongfeng
MOE Key Laboratory of High Performance Polymer Materials and Technology, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
Experimental Chemistry Teaching Center, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
Molecules. 2025 Jun 4;30(11):2466. doi: 10.3390/molecules30112466.
Polyurethane asphalt (PUA) has attracted considerable attention in the field of pavement engineering. However, traditional PUA systems typically exhibit low concentrations of polyurethane (PU), leading to a continuous bitumen-dominated phase that adversely affects mechanical properties. Furthermore, the non-renewable nature of raw materials raises environmental concerns. To address these limitations, this study developed an eco-friendly and cost-efficient bio-based PUA binder (PUAB) featuring a continuous high-biomass PU matrix (over 70% biomass) and a high bitumen content (60 wt%). The effects of the isocyanate index (NCO/OH ratio) on the cure kinetics, rheological behavior (rotational viscosity over time), viscoelasticity, damping capacity, phase morphology, thermal stability, and mechanical performance were systematically investigated using Fourier-transform infrared spectroscopy, dynamic mechanical analysis, laser-scanning confocal microscopy, and tensile testing. Key findings revealed that while the rotational viscosity of PUABs increased with a higher isocyanate index, all formulations maintained a longer allowable construction time. Specifically, the time to reach 1 Pa·s for all PUABs at 120 °C exceeded 60 min. During curing, higher isocyanate indices reduced final conversions but enhanced the storage modulus and glass transition temperatures, indicating improved rigidity and thermal resistance. Phase structure analysis demonstrated that increasing NCO/OH ratios reduced bitumen domain size while improving dispersion uniformity. Notably, the PUAB with the NCO/OH ratio of 1.3 achieved a tensile strength of 1.27 MPa and an elongation at break of 238%, representing a 49% improvement in toughness compared to the counterpart with an NCO/OH ratio = 1.1. These results demonstrate the viability of bio-based PUAB as a sustainable pavement material, offering a promising solution for environmentally friendly infrastructure development.
聚氨酯沥青（PUA）在路面工程领域引起了广泛关注。然而，传统的PUA体系通常聚氨酯（PU）含量较低，导致连续的以沥青为主导的相，这对机械性能产生不利影响。此外，原材料的不可再生性质引发了环境问题。为了解决这些局限性，本研究开发了一种环保且经济高效的生物基PUA粘结剂（PUAB），其具有连续的高生物量PU基体（生物量超过70%）和高沥青含量（60 wt%）。使用傅里叶变换红外光谱、动态力学分析、激光扫描共聚焦显微镜和拉伸试验，系统地研究了异氰酸酯指数（NCO/OH比）对固化动力学、流变行为（随时间变化的旋转粘度）、粘弹性、阻尼能力、相形态、热稳定性和机械性能的影响。关键研究结果表明，虽然PUAB的旋转粘度随着异氰酸酯指数的升高而增加，但所有配方都保持了更长的允许施工时间。具体而言，所有PUAB在120℃下达到1 Pa·s的时间超过60分钟。在固化过程中，较高的异氰酸酯指数降低了最终转化率，但提高了储能模量和玻璃化转变温度，表明刚性和耐热性得到改善。相结构分析表明，增加NCO/OH比可减小沥青域尺寸，同时提高分散均匀性。值得注意的是，NCO/OH比为1.3的PUAB的拉伸强度为1.27 MPa，断裂伸长率为238%，与NCO/OH比 = 1.1的对应物相比，韧性提高了49%。这些结果证明了生物基PUAB作为可持续路面材料的可行性，为环保基础设施发展提供了一个有前景 的解决方案。
