摘 要

混凝土材料具有抗压强度高、易浇筑成型、成本低等优点，是目前世界上用量最大、用途最广的建筑材料。但由于其为脆性材料，受外力等因素的作用容易产生裂缝，从而影响混凝土的服役寿命。因此，开发具有裂缝自修复功能的混凝土已成为研究热点。其中，微胶囊法是研究较多的一种自修复技术。所谓混凝土微胶囊自修复技术是采用壁材包覆自修复剂形成微小胶囊，将其预拌在混凝土中，当混凝土产生裂缝时微胶囊破裂，释放出修复剂使裂缝愈合。

本文以环氧树脂为囊芯，石蜡为囊壁，选择合适的分散介质，通过控制温度、时间、芯壁质量比等反应条件，制备性能优良的环氧树脂型微胶囊修复剂，利用光学显微镜（OM）、傅里叶红外光谱分析仪（FTIR）、热重法（TG）等测试技术对其化学结构及微观形貌进行表征分析，并通过包覆率及热稳定性等对其进行系统评价。实验结果表明：

（1）采用熔化分散冷凝法制备了以石蜡为囊壁，环氧树脂为嚢芯的微胶囊，在一定程度上弥补了采用原位聚合、界面聚合等化学方法所制得的微胶囊因粒径等导致的应用范围受限的问题。

（2）研究了反应温度、反应时间及囊心与囊壁质量比对微胶囊性能的影响。实验表明环氧树脂型微胶囊的制备工艺条件为反应温度为75^oC，反应时间为3h，芯壁比为1:2时，形成的微胶囊形态比较规则，粒径适中，包覆率为60%~78%。

（3）采用光学显微镜、傅里叶红外光谱、综合热分析仪等对微胶囊进行分析，通过光学显微镜观察到微胶囊呈球形，粒径适中，且不同芯壁比的微胶囊微观形貌略有差异。通过萃取法测得微胶囊的包覆率较高。在傅里叶红外光谱图上可看到环氧树脂环氧基团的特征吸收峰。由综合热分析可知产物在60.7^oC时石蜡熔化分解，在280^oC时环氧树脂开始分解，从而证明产物中含有环氧树脂。

关键词：环氧树脂；石蜡；微胶囊；熔化分散冷凝法；自修复

Abstract

Concrete materials with the advantages of high compressive strength, easy casting molding, low cost, is currently the world's largest and most widely used building materials. However, because it is a brittle material, the action of external factors cracks easily occur, affecting the service life of concrete. Therefore, the development of concrete with crack self-repair function has become a research hotspot. Among them, the microcapsule method is one of self-repair technologies. Microencapsulation technique is the use of self-repairing material coated wall formed from tiny capsules repairing agent, in which ready-mixed concrete, the concrete cracks when the microcapsules are broken, releasing agent to fix the fracture healing.

In this paper, epoxy resin as the core, paraffin, as the wall material, select the appropriate dispersion medium and surfactant, by controlling the temperature, time, core-wall ratio and other reaction conditions, prepare the self-healing epoxy resin microcapsules Excellent properties. Use an optical microscope, Malvern particle size analyzer, Fourier infrared spectroscopy (FTIR), thermal gravimetric (TG) and other testing techniques to characterize its chemical structure analysis and microstructure, and the system was evaluated by coating rate and thermal stability. This article obtained the conclusion are as follows:

(1) The microcapsules with paraffin wax and epoxy resin as the core were prepared by dispersion melting and condensation method. To some extent, it compensates for the limitation of application of microcapsules prepared by chemical methods such as in-situ polymerization, interfacial polymerization, etc.

(2)The effects of reaction temperature, reaction time and mass ratio of capsule and capsule wall on the properties of microcapsules were studied. The experimental results show that the preparation conditions of epoxy resin microcapsules is the best when the reaction temperature is 75^oC, the reaction time is 3h, and the ratio of core to wall is 1: 2, The microcapsules formed in this case are regular, and the coating rate is 60~78%.

(3) The microcapsules were analyzed by optical microscope, Fourier transform infrared spectroscopy and comprehensive thermal analyzer. The microcapsules were spherical and the particle size was moderate by optical microscope, and the microstructure of the microcapsules was slightly different. The coating rate of microcapsules was high by extraction. The characteristic absorption peaks of the epoxy groups can be seen on the Fourier transform infrared spectroscopy. From the comprehensive thermal analysis, it was found that the microcapsules were melted and decomposed at 60.7^oC. At 280^oC, the epoxy resin began to decompose, which proved that the products contained epoxy resin.

Key words: epoxy resin; paraffin; microcapsules; melting-dispersion-condensation method;

self-healing

目 录

摘 要 I

Abstract II

1 绪论 1

1.1研究背景 1

1.2自修复技术的研究现状 1

1.3微胶囊修复剂 3

1.4环氧树脂型微胶囊修复剂 7

1.5本文研究的目的及意义 9

1.6本文研究的主要内容 9

2 实验部分 10

2.1实验主要原料 10

2.2实验仪器 10

2.3实验装置图 10

2.4环氧树脂型微胶囊的制备 11

2.5微胶囊的结构表征及性能评价 11

2.5.1微胶囊包覆率的测定 11

2.5.2微胶囊的形貌表征 12

2.5.3微胶囊傅里叶变换红外光谱仪测试 12

2.5.4微胶囊的热性能测试 12

3 结果与讨论 13

3.1工艺条件对微胶囊包覆率的影响 13

3.2微胶囊的形貌 14

3.3微胶囊的红外光谱图分析 15

3.4微胶囊的热性能分析 16

4 结论 20

参考文献 21

致 谢 23

1 绪论

1.1研究背景

随着科学技术的进步和发展，金属材料、无机非金属材料、高分子材料及复合材料等材料已广泛应用于军事、工业和民用等各行各业。混凝土材料应用于建筑领域已有多年，然而由于受到压力、温度和湿度等外部条件的影响，材料在长期使用过程中可能会出现局部微损伤或内部微裂纹等问题，这些外部条件的影响将导致材料的力学性能降低等，致其使用寿命缩短。另外，人们难以用肉眼看见材料中产生的微裂纹，从而存在很大的安全隐患。因此，针对这些裂纹的材料修复技术的研究一直是国内外学术界和工程界的重要课题之一。

传统的修复形式主要是事后维修和定时维修，决定修复材料和修复方式的主要因素包括结构的开裂原因、裂缝形状、结构重要性、功能要求和环境条件等^[1]。常见的的修复方式有填充法、灌浆法、电化学防护法、表面处理法及结构加固法等。然而这些传统的修复技术需要大量的财力、物力，且不能修复材料结构深处，已经难以满足对现代材料的质量要求。