微纳观跨尺度界面增强的SBS/CNTs复合改性沥青结构-流变耦合机理

The instability of the phase structure of SBS modified asphalt is the origin of the degradation of rheological properties in its storage and transportation process. However, due to the lack of attention to the interface in traditional structural studies, it is difficult to obtain stable and durable asphalt-based composite materials. In this project, carbon nanotubes (CNTs) are used to improve the micro- and nano-scale structure. First, the key parameters for trans-scale interface enhancement design are proposed based on molecular dynamics simulation, and the interface controlling process is studied based on the Pickering emulsion polymerization method. The interface enhancement method of SBS modified asphalt will eventually establish after analyzing the difference of performance. Second, based on AFM nanoindentation and other modern microscopic testing methods, SBS phase and interface structure parameters are proposed. The SBS phase structure parameters before and after interface enhancement are investigated using microscopic observations and structural analysis method. Combined with molecular simulation and experiment, the interaction between SBS phase and interface is analyzed, and the internal causes of SBS aggregation and segregation will be revealed. Finally, the rheological properties of the modified asphalt before and after the interface enhancement are explored. With the help of the neural network algorithm and the regression fitting method, the structure-rheology coupling mechanism of the modified asphalt considering the influence of the interface is investigated. This study attempts to quantify the influence of interface structure on the stability of SBS modified asphalt, and provides a theoretical basis for the durability prediction and evaluation of asphalt materials.

SBS改性沥青相结构不稳定是其存储、运输过程中流变性能衰减的本源，而传统结构研究对界面重视不足，难以获得性能稳定、耐久的沥青基复合材料。本项目利用碳纳米管(CNTs)，从微、纳观尺度结构改善入手，首先，基于分子动力学模拟提出跨尺度界面增强设计关键参数，基于Pickering乳液聚合法研究界面调控工艺；借助界面增强前后改性沥青性能差异分析，最终建立SBS改性沥青界面增强方法。其次，基于AFM纳米压痕等现代微观测试方法，提出SBS相及界面结构参数；基于显微观测及结构分析法研究界面增强前后SBS相结构参数变化规律，结合分子模拟的界面-SBS相交互作用研究，揭示SBS相聚集、离析的内因。最后，分析界面增强前后改性沥青流变性能的变化，借助神经网络算法及回归拟合法，研究考虑界面影响的改性沥青结构-流变耦合机理。本研究尝试量化界面结构对SBS改性沥青稳定性的影响，为沥青材料耐久性预测与评价提供理论依据。

SBS改性沥青相结构不稳定是其存储、运输过程中流变性能衰减的本源，然而传统相似相容理论及化学交联理论对界面重视不足。界面诱导相分离已成为高分子科学乃至软物质科学研究的前沿课题之一，其阐述了组分浓度在界面附近涨落诱发相结构变化的问题。在沥青改性领域，界面改善相分离的研究尚未有突破。忽略界面影响难以获得性能稳定、耐久的沥青基复合材料。.本项目通过研究CNTs表面改性官能团种类、管壁数、掺量对复分子模型界面粘附力、界面形貌及沥青技术性质的影响，提出了SBS/CNTs复合改性沥青界面调控方法，明确了调控的关键参数及最佳工艺流程。通过对比不同试验方法获得复合改性沥青界面粘结强度差异、界面增强前后SBS相结构差异，认识了SBS相随时间、温度的变化规律，提出了以SBS相溶胀度、ID峰/IG峰、网络结构强度、SBS掺量表征SBS相特性的量化参数；通过分析复合改性沥青界面区分子交互作用，发现CNTs与SBS、沥青组分的缠绕、桥接的关键是π-π共轭。通过分析复合改性沥青流动活化能、复数模量主曲线、蠕变恢复率及不可恢复柔量等参数的变化，明确了界面增强对流变参数的影响；通过Cole-Cole图、Han曲线及网络结构强度分析了界面增强前后复合改性沥青结构与流变参数的相关性，明确了跨尺度增强后可有效降低网络结构强度的衰减程度，缓解SBS相的聚集与分离；通过分析聚合物相主要量化微观结构与流变参数的灰关联度，确定了复合改性沥青微观结构与流变参数相关性，以最小二乘法建立了微观参数与宏观性能的回归模型。.本项目揭示了考虑界面影响的改性沥青结构-流变耦合机制，构建了聚合物改性沥青界面稳定性理论，对数字驱动的改性沥青基因组计划实施具有促进作用。基于理论研究，进一步开发了跨尺度增强高粘沥青，其60℃粘度大于10万Pa.s、长期存储粘度不衰减，有利于薄层罩面沥青路面养护技术进一步推广。