基于纳米TiO2改性环氧树脂混凝土涂层的“原位”制备及抗氯离子渗透机理研究

Epoxy resin coating can effectively prevent the chlorine ion corrosion of rebar in concrete under the condition of marine environment. For the preparation of nano modified epoxy resin with enhanced chloride penetration resistance and excellent weather-resistance, this subject develops a novel method of nano-modified epoxy resin—one step in-situ polymerization, via combine the preparation method of nano oxide and epoxy resin, which can produce the nano material on line, and these nano material connect with epoxy resin polymerization simultaneously. The optimum conditions were obtained through the evalution of performance of this concrete coating. Moreover, we also uses various testing methods to analyze the nanoparticle size, morphology, crystal structure, as well as the mechanisms for strength and toughness of the coating. In order to reveal the mechanism of the nano modified epoxy resin, we will test the electrochemical and chemical valence state on the surface of nano oxide and rebar before and after the chloride-induced by electrochemical work station, and also analyze the chemical interaction between the titanium alkoxides groups of titania and the active groups of epoxy resin, as well as the variation of valence states and its reversible reaction, discuss the process of oxidation and reduction between chlorine ion and nano oxide. The work offers a reference and theory foundation for the reinforced concrete protective coating with excellent weather-resistance in marine environment.

环氧树脂防腐涂层可有效的防止海洋环境下氯离子对混凝土结构中钢筋的锈蚀。本项目将纳米氧化物的制备方法—纯有机均相沉积法与环氧树脂的制备过程有机结合，开发出纳米材料在线生成的同时便可与周围树脂分子进行原位聚合的纳米改性环氧树脂新工艺—在线一步原位聚合法，拟制备出抗氯离子侵蚀能力强、耐候性能优异的纳米改性环氧树脂，并通过对这种纳米复合混凝土涂层材料的各项性能的评价，确定纳米改性的最佳工艺条件。另外，综合利用各种测试手段对树脂中纳米粒子的大小、形貌、晶体结构进行分析，探讨涂膜增强增韧机理。通过研究氯离子渗透前后纳米氧化物及混凝土中钢筋表面的电化学及化学价态测试，分析纳米TiO2表面钛醇基与环氧树脂中活性基团的化学作用、纳米材料的价态变化及可逆行为，探讨氯离子与纳米氧化物之间的氧化还原过程，揭示纳米改性环氧树脂的防腐机理，为开发海洋环境中具有优异耐久性的钢筋混凝土环氧涂层材料奠定理论基础。

本项目研发的二氧化钛/环氧树脂混凝土防腐涂层有效的提高了海洋环境下钢筋混凝土抗氯离子侵蚀的能力。本项目将纳米二氧化钛的制备工艺—纯有机均相沉积法和环氧树脂的制备工艺有机结合，一步原位合成出纳米二氧化钛/环氧树脂混凝土防腐涂料，通过拉拔实验、抗折、抗压测试以及干湿循环、冻融循环等测试发现二氧化钛/环氧树脂可有效提高的混凝土的机械性能和耐久性，显著提升混凝土抗氯离子侵蚀的能力。通过热重、原位红外、X射线光电子能谱、N2吸附脱附等技术分析了二氧化钛/环氧的的孔分布、比表面积、化学键合状态，探讨了二氧化钛增强增韧环氧树脂的反应机理。通过研究二氧化钛的钛醇基和羟基与树脂基体的环氧基等极性基团的相互作用，测试氯离子渗透前后纳米二氧化钛的化学价态变化，揭示纳米二氧化钛改性环氧树脂与混凝土界面的相互作用以及防氯离子渗透机理。此外，本项目还自主研发了一种高分散石墨烯的制备方法。综合利用各种测试手段对树脂中石墨烯的分散状态、形貌、结构进行分析，探讨石墨烯对环氧涂层的增强增韧机理，同时分析了石墨烯边缘的羧基和羟基与树脂基体的极性基团的相互作用，探讨了石墨烯对环氧涂层的增强增韧机理，为开发海洋环境中具有优异耐久性的新型纳米改性环氧涂层复合材料的开发奠定理论基础。