超支化聚合物修饰碳纳米管增韧环氧沥青的开发及其固化行为研究

Epoxy asphalt mixture, the main paving material for long-span steel bridge decks , has the weakness of poor toughness and easy to crack at early stage, which may seriously affect the passage efficiency and structural safety of the bridges. Toughening modification of epoxy asphalt matrix resin is the basic approach to solve its crack resistance of pavement layers .This present project aims to synthesize different active end groups and branching degree of hyper-branched polymers, and surface covalently modified carbon nanotubes, to improve its dispersion and inter-facial bonding in the epoxy asphalt system. And large numbers of molecular branches of hyper-branched polymers play the role of flexible segment in the epoxy asphalt cross-linking network, which cooperate with the carbon nanotubes to enhance the toughening of the epoxy asphalt. Guided by the percolation model, cavitation and other toughening theories, the relationships between the micro-molecular structures and mechanical properties and toughening mechanism of epoxy asphalt containing surface modified carbon nanotubes with hyper-branched polymer are systematically analyzed. What’s more, an excellent toughening epoxy asphalt system has been developed so as to effectively solve the problem of poor cracking resistance. The influence mechanism of hyper-branched polymer modified carbon nanotubes on the curing behavior of epoxy asphalt was clarified by two-dimensional infrared correlation and non-isothermal DSC micro-analysis methods, which provides significant theoretical and application guidance for epoxy asphalt research, promotes the development and technical progress of epoxy asphalt material in steel bridge pavement in China.

环氧沥青混合料是大跨径钢桥面的主要铺装材料，但其韧性差，易发生早期开裂等病害，严重影响桥梁的通行效率甚至结构安全，对环氧沥青基体树脂增韧改性是解决其铺装层抗开裂性差的根本途径。本项目拟通过合成不同活性端基及支化度的超支化聚合物，表面共价修饰碳纳米管，改善其在环氧沥青体系中分散性及界面结合性的同时，超支化聚合物大量的分子支链在环氧沥青交联网络中起到柔性链段的作用，与碳纳米管实现对环氧沥青协同增韧，并以逾渗模型、空穴化等增韧理论为指导，系统分析超支化修饰碳纳米管改性环氧沥青不同微观分子结构与力学性能、增韧机理之间的关系，开发出具有优异增韧特性的环氧沥青体系，有效解决其抗开裂性差的问题；并通过二维相关红外、非等温DSC等微观分析手段明确超支化聚合物修饰碳纳米管对环氧沥青固化行为的影响机制，为环氧沥青研究领域提供重要的理论和应用指导，推动我国钢桥面铺装环氧沥青材料领域的发展及技术进步。

环氧沥青混合料是大跨径钢桥面的主要铺装材料，但其韧性差，易发生早期开裂等病害，严重影响桥梁的通行效率甚至结构安全，对环氧沥青基体树脂增韧改性是解决其铺装层抗开裂性差的根本途径。因此，本项目从分子设计角度出发，采用端羟基超支化聚酯和端氨基超支化聚酰胺两种不同活性端基以及不同支化度的超支化聚合物，对碳纳米管进行表面修饰，运用傅里叶红外光谱(FTIR)、热失重分析(TGA)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)等多种微观表征方法详细分析了接枝修饰前后体系分子结构的变化规律，证明了接枝修饰的成功实施；并制备了超支化聚合物修饰碳纳米管/环氧沥青复合材料，运用偏光显微镜、动态热机械分析(DMA)、应力应变曲线分析、扫描电子显微镜（SEM）等方法探讨了不同支化度以及不同活性端基超支化聚合物的引入，对碳纳米管在环氧沥青基体中的分散性、复合材料的力学性能、微观形貌等的影响规律，得到了一种环氧沥青增韧改性的高效方法；同时利用二维相关红外分析和非等温差式扫描量热法(DSC)的微观测试手段，深入分析了不同环氧沥青体系的固化反应机理及固化动力学，探讨了超支化聚合物的表面修饰对碳纳米管/环氧沥青复合材料固化行为的影响规律。本项目的研究对解决钢桥面环氧沥青铺装应用过程中存在的易开裂、施工条件苛刻等问题，推动我国钢桥面铺装环氧沥青材料领域的发展及技术进步具有重要的意义。