董邯海,程勇,程庆利,杨珂,周日峰,毕伟扬.六亚甲基二异氰酸酯微胶囊的制备及其在自修复涂料中的应用[J].表面技术,2023,52(4):272-284.
DONG Han-hai,CHENG Yong,CHENG Qing-li,YANG Ke,ZHOU Ri-feng,BI Wei-yang.Preparation of Hexamethylene Diisocyanate Microcapsules and Their Application in Self-healing Coatings[J].Surface Technology,2023,52(4):272-284 |
| 六亚甲基二异氰酸酯微胶囊的制备及其在自修复涂料中的应用 |
| Preparation of Hexamethylene Diisocyanate Microcapsules and Their Application in Self-healing Coatings |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.04.024 |
| 中文关键词: 六亚甲基二异氰酸酯 自修复涂层 微胶囊 界面聚合法 耐腐蚀 电化学阻抗谱 丝束电极 |
| 英文关键词:hexamethylene diisocyanate self-healing coating microcapsule interfacial polymerization anti-corrosion EIS WBE |
| 基金项目:中石化前瞻性基础科研项目(A-486) |
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| Author | Institution |
| DONG Han-hai | SINOPEC Research Institute of Safety Engineering Co., Ltd., Shandong Qingdao 266000, China |
| CHENG Yong | SINOPEC Petroleum Sales Co., Ltd., Beijing 100000, China |
| CHENG Qing-li | SINOPEC Research Institute of Safety Engineering Co., Ltd., Shandong Qingdao 266000, China |
| YANG Ke | SINOPEC Research Institute of Safety Engineering Co., Ltd., Shandong Qingdao 266000, China |
| ZHOU Ri-feng | SINOPEC Research Institute of Safety Engineering Co., Ltd., Shandong Qingdao 266000, China |
| BI Wei-yang | SINOPEC Research Institute of Safety Engineering Co., Ltd., Shandong Qingdao 266000, China |
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| 中文摘要: |
| 目的 制备一种基于小尺寸六亚甲基二异氰酸酯(HDI)微胶囊的自修复防腐涂料，能够提高涂层的防腐性能并实现涂层划痕缺陷的在线修复。方法 通过调整界面聚合法合成HDI微胶囊过程中的乳化剂添加量、搅拌速率和体系pH值，降低微胶囊的平均粒径，并利用囊芯染色试验、红外光谱(FTIR)、热重试验(TG)对微胶囊的结构和热稳定性进行表征。以物理共混的方式将微胶囊掺入到环氧树脂基质中制备自修复防腐涂料，使用万能拉伸机、拉拔测试仪、电化学阻抗谱(EIS)研究微胶囊对涂层基础力学性能和耐腐蚀性能的影响。结合丝束电极(WBE)测试与划痕涂层浸泡腐蚀试验分析复合涂层的内在自修复机理。 结果 确定了微胶囊制备过程的最佳乳化剂添加量为3%、搅拌速率为600 r/min、体系pH值为3.5，此时的微胶囊呈规则的球状结构，表面致密且具有一定的粗糙度，平均粒径尺寸降低为59 μm，成型率达82%。FTIR和囊芯染色试验证明微胶囊由脲醛树脂囊壁和HDI囊芯组成，TG分析显示微胶囊初始分解温度为260 ℃。随着微胶囊含量的提高，自修复涂层的拉伸断裂强度和附着力有所下降。EIS测试结果表明，含0%、1%、5%和10%微胶囊的自修复涂层经3.5% NaCl溶液浸泡144 h后，涂层电阻(Rc)分别为1.5×108、2.2×108、3.7×108、2.8×108 Ω/cm2。WBE和浸泡腐蚀试验显示，5%微胶囊掺入量的复合涂层具有最佳的划痕自修复性能，32 h浸泡后的涂层愈合效果良好。结论 当采用界面聚合法制备的HDI微胶囊均匀分散至涂层内部，可以协同提高涂层的耐腐蚀性能。此外，微胶囊能够在涂层划痕损伤位置主动释放囊芯HDI，与腐蚀溶液反应生成聚氨酯类物质填补涂层的裂纹缺陷，产生局部自愈合效果。 |
| 英文摘要: |
| A self-healing anti-corrosion coating based on small-size hexamethylene diisocyanate (HDI) microcapsules was prepared, which can improve the corrosion resistance of the coating and realize the on-line repair of coating scratch defects. This paper attempts to adjust the amount of emulsifier (from 0% to 5%), stirring rate (from 300 r/min to 700 r/min), and system pH value (from 2.5 to 4.5) in the process of synthesizing HDI microcapsules by interfacial polymerization, reduce the average particle size of microcapsules, and characterize the structure and thermal stability of microcapsules by core dyeing experiment, Flight Test Instrumentation Requirements (FTIR), and Thermogravimetric Analysis (TG). Through high-speed physical mixing, HDI microcapsules were added into epoxy resin matrix to prepare self-healing coating. The effects of HDI microcapsules on the basic mechanical properties and corrosion resistance of the coating were studied by universal tensile machine, pull-out tester, and Electrochemical Impedance Spectroscopy (EIS). In addition, the internal self-healing mechanism and self-healing ability of various composite coatings in 3.5wt.% NaCl solution were analyzed combined with Wire Beam Electrode (WBE) test and scratch coating immersion corrosion experiment. Particle size analysis of oil in water emulsion system and microcapsules morphology observation results under different reaction conditions indicated that the optimum emulsifier sodium dodecyl benzene sulfonate addition in the preparation of microcapsules was 3%, the stirring rate was 600 r/min, and the pH value of the system was 3.5. At this time, the average particle size of microcapsules was reduced to 59 μm and the molding rate reached 82%. HDI microcapsules have regular spherical structure and dense surface with certain roughness. The core dyeing experiment and FTIR showed that the microcapsule was composed of urea formaldehyde resin shell and HDI core. TG analysis revealed that the initial decomposition temperature of microcapsules with desirable thermal stability was 260 ℃, and the end decomposition temperature was 540 ℃. Along with the increase of HDI microcapsule content from 0% to 10%, the tensile strength of self-healing coating reduced from 53.24 MPa to 24.61 MPa, and the adhesion gradually decreased from 10.3 MPa to 3.9 MPa. After immersion in 3.5wt.% NaCl solution for 144 h, the fitting impedances Rp of self-healing coatings containing 0%, 1%, 5%, and 10% microcapsules were 1.5×108 Ω/cm2, 2.2×108 Ω/cm2, 3.7×108 Ω/cm2, and 2.8×108 Ω/cm2 respectively. According to WBE test and immersion corrosion test, the composite coating with 5% microcapsule content has the best self-healing performance, and the maximum corrosion current in the coating scratch position was suppressed from 4.8×10‒7 A to 2.5×10‒7 A. The Scanning Electron Microscope (SEM) photographs demonstrated that the coating scratch basically heals after 36 h immersion by the polyurethane repair materials. In conclusion, when HDI microcapsules prepared by optimized interfacial polymerization are evenly dispersed into the coating, the microcapsules improve the corrosion resistance of the coating through coordinated barrier effect. Meanwhile, the microcapsules in the self-healing coating release the core HDI at the damaged position, and quickly react with the corrosive solution to heal the scratch defects of the coating in a short period of time. |
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