自修复环氧树脂涂层及其在航空航天领域的应用

基金项目

国家自然科学基金杰出青年基金项目(22425106)和面上项目(22271139);航天进入减速与着陆技术实验室开放基金课题(EDL19092206)。

中图分类号:

V257.2

文献标识码:

A

通信作者

戈嗣诚,研究员,博士,研究方向为空间可展开柔性复合材料。

李承辉,教授,博士,研究方向为动态配位化学和自修复材料。

编辑

责编 :晓月

引文格式

高文通, 戈嗣诚, 李承辉. 自修复环氧树脂涂层及其在航空航天领域的应用[J]. 航空制造技术, 2025, 68(18): 74–87, 102.

Self-Healing Epoxy Resin Coatings and Their Application in Aerospace Fields

Citations

GAO Wentong, GE Sicheng, LI Chenghui. Self-healing epoxy resin coatings and their application in aerospace fields[J]. Aeronautical Manufacturing Technology, 2025, 68(18): 74–87, 102.

航空制造技术    第68卷    第18期    74-87,102
Aeronautical Manufacturing Techinology    Vol.68    No.18 : 74-87,102
DOI: 10.16080/j.issn1671-833x.2025.18.074
论坛 >> 自修复涂层(FORUM >> Self-Healing Coatings)

自修复环氧树脂涂层及其在航空航天领域的应用

  • 高文通 1
  • 戈嗣诚 2
  • 李承辉 3
1.南京工程学院材料科学与工程学院南京 211167
2.北京空间机电研究所北京 100094
3.南京大学化学化工学院配位化学国家重点实验室南京 210023

通信作者

戈嗣诚,研究员,博士,研究方向为空间可展开柔性复合材料。

李承辉,教授,博士,研究方向为动态配位化学和自修复材料。

基金项目

国家自然科学基金杰出青年基金项目(22425106)和面上项目(22271139);航天进入减速与着陆技术实验室开放基金课题(EDL19092206)。

中图分类号:

V257.2

文献标识码:

A

引文格式

高文通, 戈嗣诚, 李承辉. 自修复环氧树脂涂层及其在航空航天领域的应用[J]. 航空制造技术, 2025, 68(18): 74–87, 102.

摘要

随着航空航天装备服役环境日趋复杂化和极端化,传统环氧树脂涂层面临微裂纹扩展与防护性能劣化的技术瓶颈。自修复技术能够赋予环氧涂层损伤自主修复能力,显著降低失效风险。本文综述了本征型与外援型自修复环氧树脂涂层的设计原理及最新研究进展,剖析了动态共价键和非共价键的可逆修复键合机制,探讨了微胶囊和有机框架结构等载体型外援修复技术的修复增效原理。同时,针对航空航天领域应用场景下面临的强辐射和高摩擦耐受性不足、修复能量供给和损伤感知能力不足等挑战和未来发展进行了总结与展望。

关键词

自修复涂层;环氧树脂;本征型自修复;外援型自修复;航空航天防护;

Self-Healing Epoxy Resin Coatings and Their Application in Aerospace Fields

  • GAO Wentong 1
  • GE Sicheng 2
  • LI Chenghui 3
1.School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing 211167, China
2.Beijing Institute of Space Mechanics & Electricity, Beijing 100094, China
3.School of Chemistry and Chemical Engineering, State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210023, China

Citations

GAO Wentong, GE Sicheng, LI Chenghui. Self-healing epoxy resin coatings and their application in aerospace fields[J]. Aeronautical Manufacturing Technology, 2025, 68(18): 74–87, 102.

Abstract

As the service environments of aerospace equipment become increasingly complex and extreme, traditional epoxy resin coatings face technical bottlenecks such as microcrack propagation and deterioration of protective performance. Self-healing technology endows the epoxy resin coatings with damage-healing capability, thus can significantly reduce the risk of failure. This review summarizes the design principles and recent advancements in intrinsic and extrinsic self-healing epoxy resin coatings, analyzes the reversible repair bonding mechanisms of dynamic covalent and non-covalent bonds, and discusses the repair-enhancing principles of carrier-based extrinsic healing technologies such as microcapsules and organic framework structures. Furthermore, challenges including insufficient tolerance to strong radiation and high friction, inadequate repair energy supply, and limited damage-sensing capabilities in aerospace applications are addressed, along with prospects for future development.

Keywords

Self-healing coatings; Epoxy resin; Intrinsic self-healing; Extrinsic self-healing; Aerospace protection;



随着航空航天装备性能的迭代升级,其服役环境正从单一极端工况向宽温域、强辐射、高摩擦等多场耦合的复杂条件演变。环氧树脂凭借高交联密度赋予的优异力学强度、耐介质腐蚀性及界面结合力,长期稳居航空航天防护涂层树脂材料的核心地位。然而,传统环氧树脂涂层在复杂工况中长期服役时,易因微裂纹、腐蚀扩展及机械疲劳引发性能衰退,导致防护功能失效。这种失效不仅加速基体材料劣化,更可能引发装备安全隐患。因此,如何实现环氧树脂涂层材料在极端环境下的长效防护,已成为制约航空航天技术发展的瓶颈问题。

近年来,自修复涂层技术的出现为解决这一问题提供了新的思路。该技术赋予环氧树脂涂层损伤自主修复能力,通过动态恢复材料完整性实现防护性能再生,显著降低失效风险[   SONG W C, ZHAO X, JIN Z Q, et al. Development of anti-corrosion coating with sandwich-like microvascular network for realization of self-healing and self-reporting properties based on coaxial electrospinning[J]. Progress in Organic Coatings, 2024, 196: 108744.
  苏姣姣, 张雅宁, 王子聪, 等. 仿生自修复涂层研究进展[J/OL]. 高分子材料科学与工程, 2024: 1–10. (2024–11–11). http://kns.cnki.net/KCMS/detail/detail.aspx?filename=GFZC20241029001&dbname=CJFD&dbcode=CJFQ.SU Jiaojiao, ZHANG Yaning, WANG Zicong, et al. Research progress of bionic self-repairing coating[J/OL]. China Industrial Economics, 2024: 1–10. (2024–11–11). http://kns.cnki.net/KCMS/detail/detail.aspx?filename=GFZC20241029001&dbname=CJFD&dbcode=CJFQ.
1-2
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。当前自修复涂层材料的技术体系主要分为本征型与外援型两大技术路线[   王洪芹, 苏治名, 李承辉. 高弹性自修复材料的设计合成[J]. 科学通报, 2020, 65(1): 37–52.WANG Hongqin, SU Zhiming, LI Chenghui. Design and synthesis of highly stretchable self-healing materials[J]. Chinese Science Bulletin, 2020, 65(1): 37–52.
  ZHOU S W, YU C Y, CHEN M, et al. Self-healing and shape-shifting polymers controlled by dynamic bonds[J]. Smart Molecules, 2023, 1(2): e20220009.
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,本征型体系利用动态共价键和非共价键构建分子级的自修复网络;外援型体系则通过微胶囊、有机框架结构等异质相封装修复剂实现损伤响应修复。两类体系在修复效率、环境适应性等方面各具优势,其协同创新为极端环境防护提供了多维解决方案[   YIMYAI T, CRESPY D, ROHWERDER M. Corrosion-responsive self-healing coatings[J]. Advanced Materials, 2023, 35(47): 2300101.
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本文系统梳理了自修复环氧涂层的技术原理与发展趋势,重点解析了本征型与外援型体系的动态键合机制及修复增效原理,总结了目前存在的技术问题。讨论了航空航天领域应用场景下面临的强辐射和高摩擦耐受性不足、修复能量供给和损伤感知能力不足等关键技术挑战及创新进展,并对未来发展趋势进行了展望。

1     本征型自修复环氧树脂涂层

本征型自修复环氧树脂涂层技术通过环氧涂层内部动态可逆化学键网络实现损伤自主修复,当裂纹产生时,在一定外界刺激下动态化学键在界面处迅速断裂并重新结合,从而有效恢复涂层的结构与功能,其核心优势在于无须添加外援修复剂即可实现多次修复循环[   YANG Y, URBAN M W. Self-healing polymeric materials[J]. Chemical Society Reviews, 2013, 42(17): 7446–7467.
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。该体系依赖分子层面的动态键合机制,主要包括动态共价键(Diels–Alder反应、二硫键、硼酸酯键等)与非共价键(氢键、金属配位键、主客体相互作用等)。

1.1     基于动态共价键的自修复环氧树脂涂层

(1)Diels–Alder(D–A)反应。

D–A反应作为经典的[4+2]环加成反应,通过呋喃基团与马来酰亚胺的可逆环化构建动态共价网络[   WANG J T, CHEN D D, XING S L, et al. Highly thermal stable, stiff, and recyclable self-healing epoxy based on Diels–Alder reaction[J]. ACS Applied Polymer Materials, 2024, 6(1): 466–474.
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。其热可逆特性使涂层在热刺激下实现裂纹界面共价键重构,成为自修复环氧涂层研究的重点方向。Zhang等[   ZHANG Y P, YE J F, QU D A, et al. Thermo-adjusted self-healing epoxy resins based on Diels–Alder dynamic chemical reaction[J]. Polymer Engineering & Science, 2021, 61(9): 2257–2266.
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通过开环反应合成了含呋喃环的环氧前驱体,随后与双马来酰亚胺反应制备了热可逆D–A加合物自修复环氧树脂。在140 ℃下热处理40 min后,裂纹区域得到填充,并促进了分子排列的紧密性,修复后的样品抗弯强度显著高于原始样品。Amendola等[   AMENDOLA E, PALMIERI B, DELLO IACONO S, et al. Thermally mendable self-healing epoxy coating for corrosion protection in marine environments[J]. Materials, 2023, 16(5): 1775.
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通过混合D–A加成物与双酚A二缩水甘油醚单体,制备的自修复环氧树脂涂层在120 ℃加热后可有效恢复其原始形态和机械性能,并显著提升了金属基材的耐蚀性。

通过优化聚合物网络拓扑结构的策略,可有效降低含D–A动态网络的涂层修复温度。Wang等[   WANG X F, ZHAO K F, HUANG X W, et al. Preparation and properties of self-healing polyether amines based on Diels–Alder reversible covalent bonds[J]. High Performance Polymers, 2019, 31(1): 51–62.
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通过将呋喃端基修饰的聚醚胺环氧树脂与4,4′–二苯基甲烷双马来酰亚胺进行D–A加成反应,通过柔性链段的引入构建了温和条件下可修复的环氧树脂涂层,在80 ℃恒温处理12 h后,涂层裂纹修复率可达88%,拉伸强度恢复至2 MPa。

通过引入导热纳米填料的策略增强涂层内部的热传导机制,可有效提高D–A反应的修复效率。Cao等[   CAO Y, WANG X Y, WU J H, et al. A novel self-healing and removable hexagonal boron nitride/epoxy coating with excellent anti-corrosive property based on Diels–Alder reaction[J]. Progress in Organic Coatings, 2022, 173: 107209.
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设计了一种具有自修复、可去除以及可回收能力的六方氮化硼/环氧防腐涂层。如图1(a)所示[   CAO Y, WANG X Y, WU J H, et al. A novel self-healing and removable hexagonal boron nitride/epoxy coating with excellent anti-corrosive property based on Diels–Alder reaction[J]. Progress in Organic Coatings, 2022, 173: 107209.
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,该涂层通过马来酰亚胺官能团改性的六方氮化硼与同时含有呋喃和环氧官能团的环氧树脂之间的D–A反应合成,该结构中改性六方氮化硼优异的导热性能赋予了涂层材料120 ℃下的快速修复性能。

图1     基于D–A反应的自修复环氧树脂涂层
Fig.1     Self-healing epoxy resin coatings based on D–A reaction

通过引入光热反应纳米粒子,可实现光热转化触发的高效修复。如图1(b)所示,Li等[   LI Q T, JIANG M J, WU G, et al. Photothermal conversion triggered precisely targeted healing of epoxy resin based on thermoreversible Diels–Alder network and amino-functionalized carbon nanotubes[J]. ACS Applied Materials & Interfaces, 2017, 9(24): 20797–20807.
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将氨基功能化的多壁碳纳米管(NH2–MWCNTs)引入环氧树脂网络并构建了含D–A动态共价交联的涂层网络,该材料在受热(120 ℃)或近红外激光(3 W)照射条件下,均能够完全消除表面裂纹,通过调节NH2–MWCNTs含量、激光功率和激光距离,可实现对损伤区域的靶向调控修复,有效避免了能量浪费和样品变形。

(2)二硫键。

二硫键作为一种动态共价键,其断裂–重组能垒(~240 kJ/mol)显著低于常规共价键,可在热、光或机械刺激下发生可逆交换反应。利用含动态二硫键的小分子化合物作为环氧树脂固化剂,可定向构建具有动态响应特性的交联网络。Zhang等[   ZHANG B B, FAN H, XU W C, et al. Thermally triggered self-healing epoxy coating towards sustained anti-corrosion[J]. Journal of Materials Research and Technology, 2022, 17: 2684–2689.
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将2,2′–二氨基二苯二硫醚作为固化剂,制备的涂层具有优异的热触发自修复性能,在80 ℃下20 min后实现机械划痕的完全修复,并恢复金属基底的耐腐蚀性能。Singh等[   SINGH P, RAO A U, SHARMA H, et al. Microwave assisted self-repairable vitrimeric coating for anti-corrosive applications[J]. Progress in Organic Coatings, 2024, 191: 108411.
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分别以4,4′–二氨基二苯二硫醚(APD)和2,2′–二氨基二苯二硫醚作为固化剂,通过添加质量分数1%的氧化石墨烯(GO)制备了热/微波双重响应的自修复防腐涂层,微波辐照5 min即可触发修复。Wang等[   WANG B L, LI Z W, LIU X R, et al. Preparation of epoxy resin with disulfide-containing curing agent and its application in self-healing coating[J]. Materials, 2023, 16(12): 4440.
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采用二硫代二丙酸二甲酯和聚醚胺反应合成了含二硫键的固化剂,制备的环氧树脂涂层在60 ℃下6 h即可实现98%的修复效率,为传统环氧涂层寿命提升提供了低成本解决方案。

通过调控交联网络拓扑结构(如引入柔性长链和扩链剂)可进一步提升涂层性能。如图2(a)所示,Wu等[   WU J X, LIU X C, CHEN L J, et al. Rapid self-healing and high-mechanical-strength epoxy resin coatings incorporating dynamic disulfide bonds[J]. ACS Applied Polymer Materials, 2024, 6(8): 4778–4788.
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通过在环氧网络中引入动态二硫键和柔性长链二聚酸,制备了具有优异自修复和机械性能的可重复加工的环氧树脂涂层(EP–SS–DAAx),拉伸强度达35.85 MPa,柔性长链促进了分子链流动和二硫键动态交换,在60 ℃下1 h实现了93.68%的修复效率,并且可以通过热压进行再加工,拉伸强度恢复率为107.03%,且耐腐蚀性能优异。类似的,Eidi等[   EIDI M, PEDRAM M Z. Thermal induced intrinsic self-healing in epoxy based elastomer coatings provided by disulfide metathesis reactions[J]. Journal of Applied Polymer Science, 2022, 139(22): 52239.
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通过引入3,3′–二硫代丙酸作为扩链剂,能够显著提高动态二硫键环氧涂层机械强度和自修复性能,拉伸强度从0.22 MPa提升至1.25 MPa,50 ℃下2 h涂层的修复效率达到76%。

注:SHADC–1、2和3中,PDMS与APD官能团摩尔比依次为2∶1、1∶1和1∶2。
图2     基于二硫键的自修复环氧树脂涂层
Fig.2     Self-healing epoxy resin coatings based on disulfide bonds

功能化分子设计可进一步拓展动态二硫键自修复环氧树脂的应用潜力。如图2(b)所示,Wang等[   WANG X Z, HUANG X B, JI Z M, et al. Self-healing icephobic coating with UV shielding and removability based on biobased epoxy and reversible disulfide bonds[J]. Polymer, 2023, 283: 126274.
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基于亲水性的生物基环氧树脂(GTE)、疏水性的聚二甲基硅氧烷(PDMS)与4,4′–二氨基二苯二硫醚设计了具有动态二硫键的两亲性环氧自修复防冰涂层,利用GTE与水分子形成氢键实现防冰效果,同时结合低表面能的PDMS发挥除冰作用,显著提高了涂层的综合防冰性能,与裸铝相比,结冰延迟时间(802 s)增加了12.5倍,冰黏附强度(32.6 kPa)降低了84.8%倍,为开发可持续耐久型多功能抗冰涂层提供了新思路。

(3)硼酸酯键。

硼酸酯的动态键合机制源于硼酸与二元醇之间的可逆缩合反应,形成具有B—O六元环状结构的硼氧烷。Liu等[   LIU Z Y, SONG Z G, LV B R, et al. Re-assemblable, recyclable, and self-healing epoxy resin adhesive based on dynamic boronic esters[J]. Polymers, 2023, 15(16): 3488.
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创新性地将动态硼酸酯键引入环氧大豆油,开发出自修复可回收的生物基环氧树脂,通过调节硼酸酯键含量可实现4.42~13.15 MPa的机械性能调控。在90 ℃下40 min后表面划痕可完全消失,硼酸酯键与极性基团的协同作用使网络具备界面黏合重构能力。

传统热固性粉末涂料虽具有高硬度与耐腐蚀特性,但其不可逆的交联网络限制了链段流动性,导致裂纹自主修复功能缺失。针对这一局限,动态交联网络凭借快速键交换特性成为研究热点。如图3(a)所示,Liu等[   LIU Y Q, LI Z Y, ZHANG C F, et al. A self-healing thermoset epoxy modulated by dynamic boronic ester for powder coating[J]. Polymers, 2023, 15(19): 3894.
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通过调控含硼酸键的小分子二胺和改性聚氨酯预聚物的复合固化剂比例,制备出含动态硼酸酯键的热固性环氧树脂粉末涂料,其拉伸强度可达67.95 MPa,玻璃化转变温度(Tg)为51.39 ℃,可保证涂层表面的自修复能力,经1000次摩擦循环后仍可恢复原始形貌,展现出航空航天等领域的应用潜力。如图3(b)所示,Yang等[   YANG W M, YI Q X, LIU F Q, et al. Fabrication of malleable, repairable, weldable, recyclable and robust epoxy vitrimers from itaconic acid for recycled adhesion[J]. European Polymer Journal, 2023, 196: 112278.
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构建了含动态β–羟基酯键与硼酸酯键的聚碳酸酯基自修复和可回收性的刚性环氧材料,其拉伸强度达68.3 MPa,基于热诱导的酯交换反应提升了其自修复效率和焊接性能,在150 ℃下2 h表面划痕修复效率达到100%,焊接效率达到84.2%。

图3     基于硼酸酯键的自修复环氧树脂涂层
Fig.3     Self-healing epoxy resin coatings based on borate ester bonds

1.2     基于动态非共价键的自修复环氧树脂涂层

(1)氢键。

氢键作为高电负性原子(O、N)与质子受体间的定向分子间作用力,凭借其可逆重构特性成为自修复环氧树脂涂层的理想设计要素。Zhou等[   ZHOU Y, CHEN G B, YAN S G, et al. Epoxy composite coating with excellent anticorrosion and self-healing properties based on acrylate copolymers[J]. Progress in Organic Coatings, 2022, 172: 107098.
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通过自由基聚合制备了丙烯酸酯共聚物,并将其作为功能填料构筑环氧复合涂层,其动态氢键网络赋予涂层水下自主修复能力,并显著提高涂层在盐溶液中的低频阻抗,在3.5% NaCl溶液中浸泡720 h后低频阻抗为7.24×108 Ω·cm2,比纯环氧涂层高5个数量级。Wang等[   WANG J P, JIN Z Y, LIU H X, et al. Preparation and application of self-healing elastomers and coatings at ambient temperature based on semi-interpenetrating polymer networks[J]. Chemical Engineering Journal, 2024, 482: 148987.
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基于半互穿聚合物网络设计理念,以线性聚氨酯为动态相、环氧网络为刚性骨架,实现材料机械强度与自修复性能的兼顾平衡,在室温条件下修复5 min即可承受1500 mL水的载荷,在3.5% NaCl溶液中75 d后,修复后的涂层具有优异的防腐效果。如图4(a)所示,Wang等[   WANG C, HUO S Q, YE G F, et al. Strong self-healing close-loop recyclable vitrimers via complementary dynamic covalent/non-covalent bonding[J]. Chemical Engineering Journal, 2024, 500: 157418.
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进一步通过动态氢键/π–π堆积与β–羟基酯键多机制协同,设计得到高性能超支化环氧液晶聚合物,在室温下可实现96.0%的修复效率,同时机械强度高达36.0 MPa,对各种基材具有强粘附性和出色的阻燃性,其39.0%的极限氧指数和V–0阻燃等级,使其成为木材等易燃基材的出色阻燃涂料。

图4     基于氢键的自修复环氧树脂涂层
Fig.4     Self-healing epoxy resin coatings based on hydrogen bonds

构建多重动态氢键有助于提高涂层材料的修复效率和稳定性。如图4(b)所示,Liu等[   LIU T, ZHAO H C, ZHANG D W, et al. Ultrafast and high-efficient self-healing epoxy coatings with active multiple hydrogen bonds for corrosion protection[J]. Corrosion Science, 2021, 187: 109485.
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通过引入四重氢键单元2–脲基–4[1H]–嘧啶酮(UPy)并通过氨基封端的低聚丙二醇连接到环氧树脂骨架上制备了自修复环氧涂层,该涂层仅需约5 min即可在水中实现修复。电化学阻抗谱测量表明,涂层显著提高了钢基底的耐腐蚀性能,NaCl溶液浸泡60 d后的阻抗值高达4.8×1010 Ω·cm2。He等[   HE S S, CHEN J N, GAO Y J, et al. Design of self-healing and anticorrosion epoxy coating with active multiple hydrogen bonds based on grafted polyetheramine[J]. Journal of Materials Research and Technology, 2024, 33: 458–470.
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基于活性多重氢键的环氧涂层自修复设计方案,将聚醚胺(D230)链末端接枝氨基苯并噻唑合成的接枝聚醚胺(GD230)作为辅助固化剂,通过交联环氧树脂和D230与GD230混合固化剂,有效提升了涂层的自修复和防腐性能,受损的涂层在盐水中浸泡96 h后其阻抗值与空白涂层相比增加了约两个数量级。

(2)金属配位键。

金属配位键通过金属离子与有机配体的可逆键合形成,其动态特性使其在自修复环氧涂层领域具有重要应用价值。如图5(a)所示,Huang等[   HUANG Q S, ZHAO P C, LAI J C, et al. A healable, recyclable and thermochromic epoxy resin for thermally responsive smart windows[J]. Polymer Chemistry, 2022, 13(15): 2178–2186.
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基于Ni2+–咪唑配位键制备了自修复环氧树脂,所得材料具有较高的机械强度(杨氏模量达210.4~564.7 MPa),在80 ℃和0.1 MPa条件下表现出修复和重加工等热可逆特性,此外,由于Ni2+配位络合物在四配位和六配位几何结构之间的构型转变,同时赋予材料可逆的热变色行为。

图5     基于金属配位键的自修复环氧树脂涂层
Fig.5     Self-healing epoxy resin coatings based on metal coordination bonds

图5(b)所示,Dong等[   DONG A Q, LIU Q G, YAO H R, et al. Epoxy vitrimer with excellent mechanical properties and high Tg for detachable structural adhesives[J]. ACS Applied Materials & Interfaces, 2025, 17(9): 14578–14590.
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通过引入1–(3–氨基丙基)咪唑功能化侧链,在环氧网络中构建了含氢键、π–π相互作用和Zn2+)咪唑配位键的多级动态作用体系,提高了动态网络的韧性和酯交换效率,同时保证了优异的机械性能,其拉伸强度为80.3 MPa,杨氏模量为3.25 GPa,160 ℃下20 min可完成划痕修复。该策略通过网络快速重排和能量耗散的协同作用,显著提升了材料的韧性、自修复和可回收性能。Wang等[   WANG M T, XIAO G Q, WANG F, et al. Research on BN–based waterborne anticorrosive coatings integrating long-lasting anticorrosive, high cross-linking and self-healing properties[J]. Chemical Engineering Journal, 2024, 497: 154555.
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通过配位反应将Zn2+吸附在六方氮化硼(BN)表面,并利用六亚甲基二胺四亚甲基膦酸(Hdtmp)与Zn2+之间的电负性差异,促使其在BN表面形成稳定的络合物。通过将合成的BN@Zn–Hdtmp杂化材料掺入水性环氧树脂中,制备出拉伸强度36.5 MPa、黏附力9.25 MPa的耐腐蚀复合涂层,其防腐性能与纯环氧树脂涂层相比提高了两个数量级,并展现出优异的自修复性能,为水性环氧树脂的持久防腐保护提供了一种新方法。

(3)主–客体相互作用。

主客体相互作用是最常用的超分子聚合作用力之一,可以自动在主客体部分间形成高度选择性的识别,为自修复环氧涂层的制备提供了有效路径。Sugane等[   SUGANE K, MARUOKA Y, SHIBATA M. Self-healing epoxy networks based on cyclodextrin-adamantane host-guest interactions[J]. Journal of Polymer Research, 2021, 28(11): 423.
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通过硫醇–烯点击反应制备得到胺化β–环糊精,并与多官能环氧树脂及脂肪族聚醚胺交联得到含环糊精/金刚烷主客体作用的环氧胺网络。在60 ℃热激活下,动态网络通过主客体相互作用实现裂纹修复,修复效率达83%。如图6(a)所示,Hu等[   HU Z, ZHANG D Y, LU F, et al. Multistimuli-responsive intrinsic self-healing epoxy resin constructed by host-guest interactions[J]. Macromolecules, 2018, 51(14): 5294–5303.
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采用UV引发自由基聚合,将不饱和环氧树脂与β–环糊精/石墨烯络合物交联,基于主客体相互作用与石墨烯光热性能的协同机制,制备得到多刺激响应的自修复环氧防腐涂层。β–环糊精/偶氮苯功能化的GO既作为光热转化剂,又作为宏观交联剂,能够有效通过动态主客体相互作用修复损伤,在加热或近红外刺激下表现出79.2%的修复效率和高达20.8 MPa的拉伸强度。

图6     基于主客体相互作用的自修复环氧树脂涂层
Fig.6     Self-healing epoxy resin coatings based on host–guest interactions

图6(b)所示,Kurihara等[   KURIHARA R, OGAWA Y, SUGANE K, et al. Self-healing carboxylic acid-cured epoxy networks driven by the cyclodextrin-cyclohexane host-guest interaction[J]. Polymer Bulletin, 2024, 81(7): 6405–6421.
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通过β–环糊精与溴乙酸在氢氧化钾催化下反应制备羧甲基化β–环糊精,随后与山梨醇聚缩水甘油醚、聚乙二醇双羧甲基醚(PEGBC)反应得到含环糊精–环己烷主–客体结构的环氧网络(SCCPB)。研究发现,高PEGBC含量的SCCPB材料Tg较低,表现出优异的自修复性能,室温下30 s后即可显示出自修复性能,在60 ℃下24 h修复效率可达98%。

现如今,对于本征型自修复环氧树脂涂层技术而言,动态共价键体系虽能赋予环氧涂层较高的机械强度,但其修复过程往往依赖高温、特定光照或pH环境等严苛的引发条件,与实际工程应用场景存在适配性矛盾,在航空航天领域直接应用受限。以D–A体系为例,其热激活特性导致两个关键限制:(1)可逆的D–A反应需要较高的温度(约120 ℃),该修复温度与航空装备常温服役条件难以兼容;(2)多次热循环可能引发树脂基体热老化,导致材料耐久性下降。相较而言,基于动态非共价相互作用的环氧涂层具有快速响应、温和修复及环境适应性强等优势,但其分子间弱键合特性导致涂层的机械性能和环境稳定性不足,易受到周围环境中水等外界因素的干扰导致修复性能衰减。此外,高密度动态交联网络在保障修复效率的同时,往往会导致涂层材料脆性增加,不利于涂层实际涂装工艺的简化与自动化。针对上述矛盾,共价/非共价协同修复策略成为未来发展趋势。例如,通过将二硫键与UPy单体自由基共聚,构建兼具动态二硫键、多重氢键与π–π堆积结构的自修复涂层,实现机械强度与修复效率的平衡[   LIANG K, YANG Z S, ZOU Z H, et al. Surface corrosion protection designing of particulate electromagnetic material towards self-healable functional composite[J]. Progress in Organic Coatings, 2024, 188: 108251.
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;也可以在聚脲–环氧树脂体系中引入氨基嘧啶衍生物与改性GO,开发出近红外光响应的自修复防腐环氧树脂涂层,通过氢键、D–A键及π–π作用的多重动态机制协同作用使涂层在近红外光照条件下具有优异的自修复性能[   TIAN W, GUO Z L, WANG S L, et al. Hydrogen and DA bond-based self-healing epoxy-modified polyurea composite coating with anti-cavitation, anticorrosion, antifouling, and strong adhesion properties[J]. Journal of Materials Science & Technology, 2024, 187: 1–14.
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2     外援型自修复环氧树脂涂层

外援型自修复环氧树脂涂层技术通过将载有修复剂的微胶囊或有机框架结构等作为功能单元嵌入环氧树脂基体实现损伤修复。当涂层产生裂纹时,机械应力或环境刺激(如pH变化)触发微胶囊壁材(聚脲醛[   LI J Y, SHI H W, LIU F C, et al. Self-healing epoxy coating based on tung oil-containing microcapsules for corrosion protection[J]. Progress in Organic Coatings, 2021, 156: 106236.
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、聚氨酯[   FENG Y Y, CUI Y X, ZHANG M J, et al. Preparation of tung oil-loaded PU/PANI microcapsules and synergetic anti-corrosion properties of self-healing epoxy coatings[J]. Macromolecular Materials and Engineering, 2021, 306(2): 2000581.
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等)破裂,释放内部修复剂至损伤区域,通过催化聚合反应或在金属基体表面形成钝化膜实现界面修复,此外,载体型微纳结构还可通过填充增强效应同步提升涂层机械强度与介质阻隔性能。

2.1     基于微胶囊的自修复环氧树脂涂层

White等[   WHITE S R, SOTTOS N R, GEUBELLE P H, et al. Autonomic healing of polymer composites[J]. Nature, 2001, 409(6822): 794–797.
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在微胶囊载体型外援修复技术方面做了开创性研究,他们首次采用聚脲醛包裹双环戊二烯单体作为修复单元,裂纹产生时释放的单体通过Grubbs催化剂诱导的开环复分解反应实现界面修复,含10%微胶囊的环氧树脂修复后载荷恢复率达75%。随后,为提高微胶囊载体的稳定性,双壁微胶囊体系迎来持续发展。Song等[   SONG X H, MA Y X, WANG S F, et al. Crack/Cl––triggered design and tensile self-healing mechanism of epoxy coatings on offshore steel bars[J]. Progress in Organic Coatings, 2024, 196: 108753.
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通过引入硫酸铅作为壁材中的氯离子捕获剂成功制备了双壁微胶囊,在环氧树脂复合涂层中实现了优异的增韧效果和自修复性能,微胶囊的添加量与涂层的力学性能和自修复效率呈正相关。Yuan等[   YUAN W H, SHEN Y B, WANG B L, et al. Ultrafast self-healing fiber/matrix composite with single-component microcapsules loaded with cationic catalyst[J]. ACS Applied Polymer Materials, 2023, 5(3): 2016–2025.
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通过掺入负载阳离子催化剂的单组分双壳微胶囊,实现了环氧树脂微裂纹的原位即时修复,在室温下,负载15%微胶囊的环氧树脂在10 min内修复效率达95%。Adibzadeh[   ADIBZADEH E, MIRABEDINI S M, BEHZADNASAB M, et al. A novel two-component self-healing coating comprising vinyl ester resin-filled microcapsules with prolonged anticorrosion performance[J]. Progress in Organic Coatings, 2021, 154: 106220.
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采用复合凝聚和原位聚合两步法合成了含过氧化苯甲酰和乙烯基酯树脂的双层阿拉伯明胶/脲醛树脂微胶囊,负载10%微胶囊的涂层在标准盐雾试验箱中暴露50 d后仍没有腐蚀迹象,涂层在刮擦损伤后仍能持续修复,显著提高了其长效耐蚀性。此外,双组分微胶囊体系通过隔离修复组分可显著提升涂层的持续防护能力[   WU W T, CHU L Y, GARCIA S J, et al. Fabrication of graphene oxide-modified self-healing microcapsules for Cardanol-based epoxy anti-corrosion coatings[J]. Progress in Organic Coatings, 2023, 183: 107777.
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。研究表明,通过聚脲微胶囊化技术实现液态环氧树脂与胺类固化剂的物理隔离,可有效维持金属基体界面涂层的完整性和长效防护作用[   XIE C, CHENG C, ZHAO P, et al. High-performance self-healing anticorrosion epoxy coating based on microencapsulated epoxy-amine chemistry[J]. Journal of Applied Polymer Science, 2024, 141(11): e55099.
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提升微胶囊与环氧树脂基体的界面相容性对于保持自修复涂层的均一性尤为重要。如图7(a)所示,Liu等[   LIU T H, ZHAO Y Z, DENG Y N, et al. Preparation of fully epoxy resin microcapsules and their application in self-healing epoxy anti-corrosion coatings[J]. Progress in Organic Coatings, 2024, 188: 108247.
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以界面聚合法合成了以液体环氧树脂为芯,固化环氧树脂为壳的全环氧树脂微胶囊,其平均粒径43.73 μm、壳厚3 μm,引入环氧树脂基体后与涂层形成无缝界面,无相分离现象,含15%微胶囊的涂层显示出最佳的自修复能力,能够承受盐雾侵蚀超过480 h。

图7     基于微胶囊技术的自修复环氧树脂涂层
Fig.7     Self-healing epoxy resin coatings based on microcapsule technology

通过微胶囊化技术封装活性缓蚀剂成分,可规避缓蚀剂直接向涂层中添加易溶解析出的缺陷,为进一步提高环氧涂层的耐蚀性提供了新路径。如图7(b)所示,Li等[   LI J Y, SHI H W, GU S H, et al. A smart anticorrosive coating based on pH–sensitive microspheres fabricated via a facile method for protection of AA2024–T3[J]. Progress in Organic Coatings, 2024, 189: 108259.
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通过溶剂喷雾干燥技术制备了负载有2–巯基苯并噻唑抑制剂的pH响应型微球(直径2 μm),在酸性(pH<5)或碱性(pH>10)条件下表现出良好的pH刺激反应释放行为,掺入3%微球的水性自修复环氧涂层在3.5% NaCl溶液中浸泡180 d,涂层的阻抗值>1010 Ω·cm2,比纯环氧涂层高6个数量级,中性盐雾试验也证实了自修复环氧涂层具有良好的长效耐蚀性。

GO作为sp2杂化碳原子组成的二维纳米结构,凭借其独特的力学性能、光热转化能力及高比表面积,在自修复防腐涂层中展现出促进修复性和改善耐蚀性的双重优势。Li等[   LI J, TAO Z L, CUI J C, et al. Facile fabrication of dual functional graphene oxide microcapsules carrying corrosion inhibitor and encapsulating self-healing agent[J]. Polymers, 2022, 14(19): 4067.
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通过Pickering乳液自组装制备了载有缓蚀防腐剂苯并三唑(BTA)和封装环氧单体修复剂的GO微胶囊,其负载率可达90.5%。GO微胶囊同时促进了水性环氧复合涂层的防腐和自修复性能,含10%微胶囊的复合涂层自修复效率达99.7%,且完整涂层的腐蚀电流密度降低了约50倍。如图8(a)所示,Wu等[   WU K Y, CHEN Y X, ZHANG Q Q, et al. Preparation of graphene oxide/polymer hybrid microcapsules via photopolymerization for double self-healing anticorrosion coatings[J]. ACS Applied Materials & Interfaces, 2024, 16(29): 38564–38575.
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通过将GO/聚合物杂化微胶囊融入水性环氧树脂,制备了一种具有双重自修复性能的防腐涂层,当涂层被划伤时,包裹在微胶囊中的亚麻籽油实现裂纹填充,GO的光热转换特性可以在近红外照射下促进损伤区域的分子链运动实现裂纹闭合,填充与闭合的双重修复显著提高了涂层的耐蚀性,修复涂层的阻抗模值(|Z|0.1 Hz值)与完整涂层相当,比空白涂层高出约4个数量级,中性盐雾试验中修复涂层在300 h后没有出现任何腐蚀。如图8(b)所示,Zhao等[   ZHAO P Y, YAN J, YAN H M, et al. Wear and corrosion resistance of self-healing epoxy coatings filled by polydopamine-modified graphene oxide assembly of polysulfone double-walled microcapsules[J]. Progress in Organic Coatings, 2023, 177: 107416.
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通过将聚多巴胺(PDA)改性后GO组装到聚砜外壳层上,制备了一种双层微胶囊填充环氧树脂涂层,显著提升了机械性能和热稳定性,负载10.0%微胶囊的涂层阻抗值和低频阻抗模量分别提高了17.5倍和10.7倍,并表现出优异的划痕自修复性能。

图8     基于GO改性微胶囊的自修复环氧树脂涂层
Fig.8     Self-healing epoxy resin coatings based on GO-modified microcapsule

2.2     基于有机框架结构的自修复环氧树脂涂层

有机框架结构(如金属–有机框架MOFs、共价有机框架COFs)作为新型功能载体,凭借其规则纳米孔道、超高比表面积及可设计化学环境的特点,可精准包覆缓蚀剂或单体修复剂,近年来在自修复防腐涂层领域受到广泛关注。沸石咪唑骨架(ZIFs)作为MOFs的一个子家族,由金属离子和咪唑或其衍生物组成。Zhang等[   ZHANG M, WAN J R, WANG J, et al. Smart self-healing coating with multiple synergistic effects based on ZIF–11 for corrosion protection of carbon steel[J]. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2024, 684: 133186.
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制备了ZIF骨架结构并采用聚丙烯酸铈聚合物对其进行包覆,与环氧树脂复合得到自修复防腐涂层,基于其pH刺激响应释放的苯并咪唑、Zn2+和Ce3+的多重协同效应,可形成金属氢氧化物沉淀层和金属–咪唑配合物自修复保护层从而实现长效防护。Wei等[   WEI K, WEI Y K, ZHANG Y, et al. In Situ synthesis of ZIF–8 loaded with 8–hydroxyquinoline composite via a host-guest nanoconfinement strategy for high-performance corrosion protection[J]. Corrosion Science, 2024, 227: 111731.
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基于原位主客体纳米限域策略,在室温下通过一步法合成了ZIF结构负载腐蚀抑制剂8–羟基喹啉(8–HQ)的复合涂层,其pH响应性实现8–HQ的调控释放,在腐蚀性溶液中2 d后铝合金基材的腐蚀抑制率超过91%。

Liu等[   LIU T F, LIU Y S, QU D R, et al. Smart self-healing coating based on the covalent organic frameworks (COF LZU–1) for corrosion protection of steel[J]. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2024, 685: 133246.
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通过水热法合成了一种COF多孔化合物,并将BTA缓蚀剂负载到其中,用于自修复环氧树脂涂层的制备,COF中的氨基可与环氧基团反应提高负载结构在涂层中的分散性,负载的BTA可在酸性或碱性条件下实现有效的pH响应释放,在受损暴露的金属表面形成钝化层从而实现涂层的自修复和长效防护。

载体型修复剂作为实现环氧涂层外援自修复功能的关键组成,其制备与应用仍存在多重技术瓶颈:(1)微胶囊的几何参数(尺寸、形貌)与结构特性(壁材强度、芯材活性)直接影响修复效率,但现有制备工艺难以实现高精度调控。生产过程中微胶囊易发生破损或芯材渗漏,导致贮存稳定性下降。因此,稳定优化的生产制备工艺对于提高微胶囊的修复效率显得尤为重要。(2)微胶囊与涂层树脂的界面相容性制约其工程应用。壁材与树脂基体间的极性差异易引发界面微相分离,造成局部应力集中并削弱涂层机械性能。同时,微胶囊在基体中的非均匀分布会导致损伤区域修复物质供给不足,并影响实际涂装的稳定性和均一性。通过表面接枝改性或偶联剂处理[   SUN W H, TANG E J, ZHAO L L, et al. The waterborne epoxy composite coatings with modified graphene oxide nanosheet supported zinc ion and its self-healing anticorrosion properties[J]. Progress in Organic Coatings, 2023, 182: 107609.
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可增强界面化学键合和相容性。(3)修复剂负载效率与涂层防护性能的平衡难题亟待解决。过量添加微胶囊虽能提升修复容量,但会导致涂层孔隙率上升与介质阻隔能力下降。通过核壳结构设计与壁材多孔化改性[   ZHANG Y Y, XING J J, TIAN H, et al. Smart nanoarchitectonics of epoxy coating: Preparation, release behavior and self-healing performance based on mesoporous silica nano-containers loaded with DMTD inhibitors[J]. Materials Today Communications, 2024, 39: 108673.
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,可在有限添加量下显著提升芯材装载率,实现修复效能与涂层完整性的协同优化。(4)基于有机框架结构和多壳层微胶囊的载体型修复剂目前仍面临合成步骤烦琐、生产工艺复杂和综合成本较高等实际应用难题。

3     航空航天领域应用的挑战与展望

当前自修复环氧树脂涂层在航空航天领域的应用面临多维度的极端环境耦合挑战,其技术瓶颈的突破直接关系到飞行器的服役安全与寿命周期[   PAOLILLO S, BOSE R K, SANTANA M H, et al. Intrinsic self-healing epoxies in polymer matrix composites (PMCs) for aerospace applications[J]. Polymers, 2021, 13(2): 201.
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。针对航天领域如空间航天器等典型工况,涂层系统需要在太空强辐射的环境中维持功能稳定性;针对航空领域如飞机蒙皮等典型工况,涂层系统需要在飞行高摩擦的环境中维持功能稳定性。同时,两者均面临修复能量供给和损伤感知能力不足的挑战,这对涂层体系的耐受性、响应速度及功能协同性提出了更高的要求。

3.1     强辐射耐受性不足

航天装备所处的太空环境存在高能紫外线及宇宙射线,会引发环氧树脂分子链中C—C、C—O等化学键发生断裂生成羟基自由基(·OH)等,一方面使涂层在辐照后面临机械性能退化的风险;另一方面自修复机制(如二硫键)可能因自由基破坏动态交换活性位点而失效。因此,开发具有辐射屏蔽和高耐受性的自修复环氧树脂涂层对与维持航天器舱体密封性和保证长期在轨任务的安全性具有重要意义。

对此,燕山大学王海燕团队进行了系列探索性工作,2021年设计了SiO2/ZnO复合壳层的环氧树脂微胶囊自修复系统,超细ZnO纳米晶体均匀嵌入介孔SiO2壳中,赋予微胶囊优异的紫外线屏蔽性能,在紫外线辐射下老化21 d后仍显示出良好的修复性能[   LI P H, GUO W C, LU Z, et al. UV-responsive single-microcapsule self-healing material with enhanced UV–shielding SiO2/ZnO hybrid shell for potential application in space coatings[J]. Progress in Organic Coatings, 2021, 151: 106046.
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。2022年进一步构建了SiO2/PDA杂化微胶囊,该外壳将超薄PDA层均匀嵌入外壳SiO2介孔结构中,作为紫外线吸收剂,PDA为微胶囊赋予了紫外线屏蔽杂化外壳,使核芯材料免受紫外线辐照提前固化[   LI P H, LU Z, MA K X, et al. UV–triggered self-healing SiO2/PDA hybrid microcapsules with both enhanced UV-shielding ability and improved compatibility for epoxy resin coating[J]. Progress in Organic Coatings, 2022, 163: 106636.
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。2023年,团队将具有优异紫外吸收性能的CeO2纳米粒子均匀地嵌入外壳SiO2介孔结构中,含有SiO2/CeO2微胶囊的环氧涂层在紫外光下576 h后仍保持优异的自修复性能[   LI P H, ZOU G F, CHANG L, et al. UV–stimulated self-healing SiO2/CeO2 microcapsule with excellent UV-blocking capability in epoxy coating[J]. Bulletin of Materials Science, 2023, 46(3): 159.
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。团队还发现在微孔SiO2壳层中沉积具有共轭特征的酚醛树脂,通过光诱导电荷从电子供体的间苯二酚单元转移到电子受体的间苯二酚醌单元,亦可为环氧涂层提供独特的紫外辐射吸收能力,是提高其在航天器涂层中长期使用稳定性的有效策略[   LI P H, GUO W C, MA K X, et al. Resorcinol-formaldehyde resin with donor-acceptor couples to enhance the long-term service stability of a single UV–triggered self-healing SiO2@RF microcapsule for potential application in a UV–sufficient space environment[J]. Applied Surface Science, 2023, 616: 156537.
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。此外,在微胶囊壳壁中嵌入改性纳米氧化钨WO3颗粒,负载3.5%微胶囊的自修复环氧树脂涂层可在γ射线照射下保持较长时间的结构稳定性[   ADAMS W T, BRECHIN B, TRUONG T T. Preparation and characterization of tungsten oxide fortified poly(urea-formaldehyde) microcapsules for self-healing coatings[J]. Polymer Testing, 2024, 131: 108328.
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3.2     高摩擦耐受性不足

航空装备在高速飞行中面临来自大气层的长期高频摩擦考验,一方面常规自修复体系在高频摩擦应力下修复速率不足,难以维持涂层的完整性和使用寿命;另一方面外援型如微胶囊的引入虽能修复裂纹,但会降低涂层致密度,在高频摩擦工况下修复剂释放后形成的孔隙会成为应力集中点,加速涂层磨损。因此,开发兼具高耐磨性与自修复性的环氧树脂涂层对于保障航空装备气动稳定性显得尤为重要。

Yang等[   YANG K, NIU Y P, WANG X W, et al. Self-lubricating epoxy composite coating with linseed oil microcapsule self-healing functionality[J]. Journal of Applied Polymer Science, 2024, 141(6): e54927.
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通过耦合自润滑和自修复技术来改善环氧树脂的摩擦性能,通过原位聚合合成了平均粒径38.57 μm的亚麻籽油微胶囊,并制备了具有优异自润滑性能的复合涂层,掺杂10%亚麻籽油微胶囊使得涂层摩擦系数从纯环氧树脂的0.634降低到0.0459,磨损率从7.16×10–4 mm3/(N·m)降低到1.74×10–5 mm3/(N·m),同时微胶囊破裂后释放的亚麻籽油可以通过在摩擦过程中与氧气反应实现磨损修复。

Maleki等[   MALEKI A, VAFAEENEZHAD H, ESLAMI-FARSANI R. Polystyrene microcapsules containing linseed oil and SiC nanoparticles as a lubricant additive for boosting the self-healing and self-lubricating efficiency of epoxy coatings[J]. Tribology International, 2024, 193: 109428.
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通过嵌入亚麻籽油填充微胶囊和SiC纳米颗粒得到纳米复合环氧涂层,显著提升了涂层的耐磨性和润滑性能,与纯环氧涂层相比,含有3% SiC纳米颗粒的涂层摩擦系数降低了31.79%,比磨损率降低了59.04%。Hasan等[   HASAN A, ESLAMI-FARSANI R, EBRAHIMNEZHAD-KHALJIRI H. Effect of ZrO2 nanoparticles on the self-lubrication behavior of the linseed oil-loaded microcapsule/epoxy composite coatings[J]. Ceramics International, 2024, 50(19): 36544–36554.
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研究了ZrO2纳米颗粒对亚麻籽油微胶囊/环氧复合涂层自润滑行为的影响,当ZrO2纳米粒子的含量增加到9%时,获得了0.085和0.142×10–6 mm3/(N·m)的最低摩擦系数和磨损率,分别比纯环氧涂层降低82%和88%。Li等[   LI X, LI Z K, LUO H X, et al. Dual-function double-walled microcapsules effectively improve the wear resistance and anticorrosion of epoxy composite coatings[J]. ACS Applied Polymer Materials, 2024, 6(17): 10334–10345.
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通过引入PDA修饰的聚脲醛/GO双壁微胶囊,显著提升了环氧树脂涂层的耐磨性和耐蚀性,填充10%微胶囊的环氧涂层摩擦系数从0.691降低到0.039,摩擦系数和磨损率分别比纯环氧涂层低94.3%和87.8%,磨损深度从19.923 μm降低到6.102 μm,为开发具有高耐磨和高耐蚀双重功能的聚合物涂层提供了新思路。

3.3     修复能量供给不足

深空环境中缺乏稳定热源且无法对外表面涂层材料直接加热修复,从而导致现有热触发型自修复体系因能量输入不足导致失去修复防护功能。在飞行器运行过程中将富余的光能吸收转化为局域热能,开发具有高效光热转化能力的自修复涂层,实现无外接热源条件下的自主修复,才可有效避免热触发型自修复涂层因能量供给不足导致的损伤累积。

Hao等[   HAO Z T, CHEN S, LIN Z F, et al. Anticorrosive composite self-healing coating enabled by solar irradiation[J]. Frontiers of Chemical Science and Engineering, 2022, 16(9): 1355–1366.
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通过在环氧树脂中添加Fe3O4纳米颗粒和十四烷醇,构建了一种阳光下具有自修复功能的复合涂层,Fe3O4赋予涂层良好的光热性能,十四烷醇的相变特性使涂层在低温下能够流动填补裂纹并实现快速自修复。如图9(a)所示,Lai等[   LAI X, HU J F, QU J Q. Rational design of photothermally activated self-healing coating with UV resistance towards smart corrosion protection[J]. Progress in Organic Coatings, 2024, 195: 108674.
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开发的聚己内酯微球复合体系通过掺杂BTA和PDA改性的氧化铈,同步实现自修复环氧涂层的光热修复与紫外线防护。该涂层在200 mW/cm2光照下10 min即完成损伤修复,紫外辐照120 h后仍保持稳定的阻抗模量值(3.62×108 Ω·cm2)。

图9     智能化自修复环氧树脂涂层
Fig.9     Smart self-healing epoxy resin coatings

Zhang等[   张青青, 陈亚鑫, 刘仁, 等. 基于聚苯胺微胶囊的双重自修复防腐涂层[J]. 高分子学报, 2023, 54(5): 720–730.ZHANG Qingqing, CHEN Yaxin, LIU Ren, et al. Dual-action self-healing anticorrosive coating based on polyaniline microcapsules[J]. Acta Polymerica Sinica, 2023, 54(5): 720–730.
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通过将聚苯胺微胶囊与亚麻籽油结合并嵌入水性环氧树脂涂层,构建了具有优异光热转换能力的双重自修复防腐涂层,聚苯胺的光热转化特性赋予涂层近红外光照射下的快速修复能力,负载10%微胶囊的涂层光照3 s即可实现快速修复并恢复其阻隔性能。Wang等[   WANG J K, MA L W, HUANG Y, et al. Photothermally activated self-healing protective coating based on the “close and seal” dual-action mechanisms[J]. Composites Part B: Engineering, 2022, 231: 109574.
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将形状记忆环氧树脂基体与负载光热转换能力氮化钛纳米粒子(TiN)的聚己内酯微球相结合,制备了对近红外激光和阳光都具有优异光热响应的双重自修复涂层,近红外照射下30 s即可恢复阻隔性能。此外,光热转换可以加速涂层划痕周围水分的蒸发,从而抑制受损区域的腐蚀活动。

3.4     损伤感知能力不足

航空航天装备涂层不仅需自主修复损伤,更需具备自预警功能以提前感知隐患。而常规自修复体系无法在裂纹萌生初期通过颜色示警等信号提示损伤位置,导致装备在检修时难以及时定位问题区域,可能错失最佳修复窗口[   GONG W Q, CHENG J, PI D D, et al. Monitoring fluorescence to identify cracks in self-healing coated fabric of thermal-induced microcapsules[J]. ACS Applied Polymer Materials, 2024, 6(18): 11457–11464.
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。因此,开发具有原位损伤感知与智能响应功能的自预警自修复环氧树脂涂层对降低在轨维护成本、保证飞行器安全具有重要意义。

图9(b)所示,Wang等[   WANG Y, JIN H F, WANG J K, et al. Effect of crosslinking density on the self-healing and self-reporting properties of epoxy anti-corrosion coatings[J]. Progress in Organic Coatings, 2024, 195: 108683.
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将2,7′–二氯荧光素(DCF)和亚麻籽油分别作为着色剂和修复剂封装在微胶囊中,开发了具有自预警和自修复功能的环氧涂层。当涂层受损时,DCF释放并与环氧基体中的残留氨基反应,在自然光下呈现红色标记,紫外光激发下显示黄色荧光,实现损伤区域双模式可视化定位。同时释放的亚麻籽油在形状记忆效应驱动下填充裂纹,完成自主修复。

Liu等[   LIU J G, HUANG W R, ZHANG K L, et al. Early warning and self-repair properties of O–phenanthroline modified graphene oxide anti-corrosion coating[J]. Progress in Organic Coatings, 2024, 189: 108274.
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采用脱水缩合法将1,10–邻菲咯啉–5–胺接枝到GO上,并以亚麻籽油进行交联改性并作为芯材(PGO)制备了微胶囊,当PGO和微胶囊添加量分别为0.3%和15%时,复合涂层显示出最佳的自预警、自修复和防腐性能,损伤部位5 min内显现红色示警信号,修复率为95.92%,涂层防腐性能提升10倍。Song等[   SONG Y K, LEE T H, LEE K C, et al. Coating that self-reports cracking and healing using microcapsules loaded with a single AIE fluorophore[J]. Applied Surface Science, 2020, 511: 145556.
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采用单分子聚集诱导发光荧光染料构建的微胶囊赋予涂层自预警和自修复双重功能,划痕产生后立即呈现弱红色荧光,随着修复过程的进行荧光渐变为橙色,可实现对裂纹修复过程的实时可视化追踪。

4     结论

自修复环氧树脂涂层作为航空航天领域极具潜力的智能防护技术,其工程化应用仍面临材料性能与工程需求失衡的瓶颈:本征型体系依赖外部能量输入且动态键网络在极端环境下易失活;外援型修复受限于循环次数与异质相掺杂引发的致密性下降问题,均难以匹配航空航天装备的全生命周期防护要求。未来需通过多维度协同创新突破技术壁垒。

(1)本征型与外援型修复的协同设计为涂层性能优化提供新路径。通过构建共价/非共价键双网络仿生结构,实现涂层修复效率与防护效果的同步提升,结合形状记忆环氧基体实现涂层损伤区域的主动形变修复,并逐步引入光热/pH等多重响应感知能力,赋予涂层复杂环境下的多模式修复能力。

(2)多功能纳米粒子的复合应用为涂层极端环境适配性提供可能。基于B4C、MXene和GO等纳米粒子的复合改性技术,开发耐紫外辐照、低表面能及抗静电的多功能涂层体系,满足航天器抗空间辐照、月尘防护等特殊环境防护需求。

(3)智能响应体系的构建可推动自修复涂层功能的一体化升级。面向航空航天装备特需场景,开发环境响应变色材料实现损伤原位可视化监测,通过超疏水–自修复协同界面优化飞机蒙皮抗冰性能,形成感知–修复一体化的智能防护架构。

(4)自修复涂层构效评价体系的建立可加快其走向实际应用。开发自修复涂层构效关系的跨尺度理论模型,建立“动态键特性–网络结构–宏观性能”的定量构效关系,实现涵盖修复效率、环境耐久性与机械稳定性的多维度评价标准,为材料筛选与工程验证提供量化依据。

作者介绍



高文通 副教授,博士,研究方向为自修复高分子材料。

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