Role of Chemical Bonding on Durability of Epoxy Adhesion to Mortar

化学键对环氧砂浆粘合耐久性的作用

• 批准号: 0653969
• 负责人: Elliot Douglas
• 金额: --
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0653969&HistoricalAwards=false
• 关键词: Role; Chemical; Bonding; Durability; Epoxy

This grant provides funding to investigate the chemical interactions at the interface between epoxy and cement paste or mortar, and the effect of water on those interactions. Based on what is known about the surface chemistry of cement paste, and by analogy with epoxy adhesion to aluminum, we propose that epoxy forms hydrogen bonds with cement paste. In the presence of water, these water-cement paste bonds are displaced by the water molecules, leading to a weakening of the interface. We propose to test this hypothesis through a combination of spectroscopic and mechanical measurements. The surface chemistry of epoxy, cement paste, and mortar will be identified using x-ray photoelectron spectroscopy (XPS) and attenuated total reflection infrared spectroscopy (ATR-IR). Bonding between the two will be identified by placing a thin epoxy coating on the cement paste or mortar and identifying the bonds with XPS and ATR-IR. The role of hydrogen bonds will be quantified by modifying the surfaces to change the surface concentration of hydrogen bonds and by quantitative analysis of the XPS and ATR-IR spectra. The effect of water will be identified using both spectroscopic and mechanical measurements on specimens that have been immersed at 30, 40, 50, or 60 C for up to 12 weeks. Direct tension pull-off tests will be used to measure changes in bond strength as a function of immersion and surface treatment and correlated to the changes in bonding observed with XPS and ATR-IR.This project will provide new insights into the adhesion between epoxy and cement paste and how environmental exposure affects that adhesion and the resulting properties. The primary objective of the project is to provide the fundamental science needed to understand the behavior of these materials when used in real-world applications. The results may be used to develop improved models of aging for lifetime prediction of systems in which epoxy is bonded to cement. It may also provide guidance for developing new materials with improved performance and lifetime.

该基金提供资金用于研究环氧树脂和水泥浆或砂浆之间界面的化学相互作用，以及水对这些相互作用的影响。 基于什么是已知的水泥浆的表面化学，并通过类比与环氧树脂粘附铝，我们建议，环氧树脂形成氢键与水泥浆。 在水的存在下，这些水-水泥浆体键被水分子取代，导致界面弱化。 我们建议通过光谱测量和机械测量的结合来检验这一假设。 将使用X射线光电子能谱（XPS）和衰减全反射红外光谱（ATR-IR）鉴定环氧树脂、水泥浆和砂浆的表面化学。 将通过在水泥浆或砂浆上放置薄的环氧树脂涂层并通过XPS和ATR-IR识别键来识别两者之间的键合。通过修饰表面以改变氢键的表面浓度并通过XPS和ATR-IR光谱的定量分析来量化氢键的作用。 将使用光谱和机械测量对在30、40、50或60 ℃下浸泡长达12周的样本进行鉴定水的影响。 直接拉伸拉脱试验将用于测量浸泡和表面处理后粘结强度的变化，并与XPS和ATR-IR观察到的粘结变化相关联。该项目将为环氧树脂和水泥浆之间的粘附力以及环境暴露如何影响粘附力和由此产生的性能提供新的见解。 该项目的主要目标是提供了解这些材料在实际应用中的行为所需的基础科学。 研究结果可用于开发改进的老化模型，用于环氧树脂与水泥粘结系统的寿命预测。 它还可以为开发具有改进性能和寿命的新材料提供指导。