- Email: [email protected]
Enhancements in self-curing composites
Enhancements in self-curing composites
10
Hakan Burhan, Suna Saygili and Fatih Sen ¸ Sen Research Group, Department of Biochemistry, Dumlupınar University, Ku¨tahya, Turkey
10.1
Introduction
A lot of research has been done to facilitate human life throughout the history of humankind, and most of them have been successful. Nowadays, thanks to the rapid advancement of technology, the needs of many smart and new materials have increased, and it has become more functional by developing existing products. Polymeric materials can be used as an example for meeting these needs. Polymeric materials are preferred in many areas due to their light, inexpensive, and easyprocessing properties compared to metal and ceramic products among traditional materials [1]. In addition to the properties of the polymers, their corrosion stability and good metallic properties are present. However, the presence of environmental stability, as well as low conductivity, chemical and thermal stability are among the disadvantages of polymers [2]. The polymer composite products to be obtained in order to get rid of the disadvantages of the polymers have been used in order to improve their matrices by getting help from a wide variety of filling materials. In order to increase the performance required in the present products, there is the possibility of being supplemented by many fillers (particles, fibers or platelets, synthetic or natural, organic or inorganic) regardless of the scale of the polymer matrix (macro, micro, or nano) [3 6]. The presence of self-healing materials and their development is seen as an area of great interest as it will significantly facilitate human life [7 11]. The basic principle of these materials is the encapsulation of healing agents in the matrix of materials that can be broken or cracked. When any cracking or cracking on the material results in the destruction of the capsule of the crack-improving agent, the scavenging agents spread along the crack and bind the resulting gap [12]. Thanks to this feature, as it is seen that self-healing materials can be produced in various fields and applications. In the preparation of self-healing materials, when used in the literature, it is observed that they are curative agents such as polydimethylsiloxane (PDMS), dicyclopentadiene, and epoxy [13 21]. However, epoxies among these therapeutic agents have not yet been produced in any material [22 25]. The reason for this Self-Healing Composite Materials. DOI: https://doi.org/10.1016/B978-0-12-817354-1.00010-7 © 2020 Elsevier Inc. All rights reserved.
178
Self-Healing Composite Materials
failure is that it is due to the problems of microencapsulation of hardeners suitable for epoxy curing [26]. Amine-type curing agents are traditionally used for the curing of the epoxy, and they have a very active feature at room temperature. Therefore it is not possible to encapsulate epoxy in water or organic solvents [27 30]. Information on the encapsulation of curing agents is relatively low in the literature. Among these data, it was observed that several researchers tried to develop self-healing materials by using the in situ technique. Informing this process, monomers and enhancers were added to the water and agitated to prepare encapsulated curative agents [26,30 32]. However, due to the difficulty in maintaining the system pH and the lack of polymerization of the monomers, shell materials were used in the final applications. The spontaneous recovery that occurs on living things can be complicated or leave an interesting effect [12]. We can see that other damage can repair itself unless the damage is very severe or vital in the organ. For example, cracks or fractures in a scratch or bone that occur on the skin can be repaired and regained itself. This system of healing is known as a vascular system in mammals. Blood flow is observed as a result of a scratch on the human skin. Hemorrhage helps to transport the healing area to the wound site using blood vessels. The process that started here is repaired by a system that works quickly, such as stopping the bleeding in the wound area, failure to progress, and a shell on the wound. This spontaneous healing process in living things has encouraged a variety of studies to be done for engineering materials [23,33 35]. Micro- and macro-nanofibrils or tubes which function the same when compared to the mammalian blood vessels produce materials that can recover spontaneously. With the help of nanofibrils, healing agents transmitted through blood vessels, epoxy resin, resin monomers, and hardeners can also be delivered in engineering materials. The healing agents stored in the matrix of the materials in the encapsulated state are released, polymerized, or solidified by cracks resulting from damage. In this way, broken fiber ends are combined [33,35 37]. If the damage to the material triggers a condition related to crack propagation, the self-healing process can prevent crack growth without being irreversible. Propagation of particular cracks on composite materials is useful in decomposition of composites. Most composite materials are highly vulnerable to these cracks [35,38,39]. It is difficult to correct these damages as well as detect this crack on the composite. The formation of a small crack on the composite material may cause the entire structure to deteriorate over time. In the areas where these materials are used, support or replacement materials should be placed for security purposes by considering these risks. The self-healing system is very important in eliminating damage such as flexures [33,35], stresses [40,41], and delamination of composite materials [42,43]. The healing agents can entirely or partially recover the hardness factor of the material in the damaged area. In addition to this, corrosion protection of the materials is ensured using anticorrosion coatings in order to solve the corrosion problems of materials and self-healing is achieved [44 46]. Some studies may be done before.
Enhancements in self-curing composites
179
It has been observed that the previously drawn cracks of the materials exposed to static stress can self-heal [47].
10.2
Self-healing composites: dispersed agents
A wound that occurs in the skin of mammals is repaired by the spontaneous healing feature of the organism. The blood stopper and coagulating agents in the circulatory system of life are the role models for the engineering materials to be repaired in this way. The self-healing agents can be especially liquid and solid. As seen in Fig. 10.1, the different components (A) may be in the form of a manual material crack, (B) in the material matrix, or (C) in the form of a combination of coupling and injection [48]. It is observed that the recovery efficiency in the epoxy material system for selfhealing varies according to the method of use [48]. This change can be between 38% and 99%, as well as an improvement of up to 119% due to epoxy chemistry [49,50].
10.2.1 Encapsulation The capturing of catalysts in microcapsules or cross-linking reactants developed has been studied [51]. However, expansion studies have been followed to have the
Figure 10.1 Three methods of inclusion for the healing agents and catalyst in a composite: (A) injection; (B) incorporation; (C) a combination of injection & incorporation [51].
180
Self-Healing Composite Materials
ingredients required for polymer coatings in capsule formation [52]. When these microcapsules were found to be broken under a light pressure on them, it was inevitable to use them in the textile industry in 1978 [53]. Later, as a result of making the curing agents into a capsule and being able to participate in other materials, it has paved the way for its use in biographical wound healing. Furthermore, self-healing and protective materials are now being developed on composite materials [54]. The encapsulation of the curative agents can be achieved by using hollow fibers, nanotubes [55], or microspheres [56]. Some discussions between these types of encapsulation have been inevitable, and the concentrations and dispersions of the catalysts and curing agents used for this process have also been discussed. A hollow fiber material was designed in the matrix to provide self-repairable feature between the composite materials. Another example of self-recovering polymer materials is the hollow glass pipette tubes which are contain the cyanoacrylate resin [57]. On the other hand, other materials could be used as hollow fibers or capillaries [21]. It is more preferred than capillaries such as copper and aluminum because of the easier breakability of the existing glass capillaries. The easy breaking of the glass capillary makes it easier for the resin to flow into the crack. The material required for another self-healing recovery is the nanotubes. Carbon nanotubes (CNTs) [58] are widely preferred for their many properties. Its main characteristics are its impressive mechanical properties for polymer strengths and additional resistance potentials [59]. Also, electrical resistance based detection [60] features are used. The origin of composite materials is already known to contain CNT. This provides information that CNTs can heal themselves [61]. The use of CNTs in a curative system can only work if they are injected into the CNTs and the CNTs are ruptured to release the encapsulated enhancement agents. Studies on CNTs have shown a high degree of success in their work [62]; however, they are not used as reservoirs in addition to their use as reinforcements [63]. The questioning of the healing properties of CNTs [64 73] is that they are very strong and will not tear. Besides, the concerns about nanotubes are due to their small diameters and resin viscosity. However, the above situation is not the case for SiO2polymeric hybrid nanotubes [74]. Polyelectrolyte nanocapsules [75] are therefore recommended for anticorrosion coatings. A new polymer has been developed in recent studies on self-healing [12]. Due to the microcapsules in the matrix, the life of the polymeric components is increased. It promises that any microcracks that may occur on the composite materials can be improved autonomously and that the life span can be significantly extended. Fig. 10.2 illustrates the concept of microcapsules. As a result of a crack on the material, the healing process takes place using microcapsules in an epoxy matrix. The curing agents contained in these capsules include the catalytic chemical trigger, allowing the crack to close. Cracking on the composite material leads to the explosion of microcapsules with curative agents through capillary action. The resulting therapeutic agents contact the broken surfaces in contact with the catalyst embedded in the material and initiate the coupling. Thanks to the microcapsules, as the self-healing of the material can be 90% [76].
Enhancements in self-curing composites
181
Figure 10.2 Spontaneous recovery [73]. The composite matrix comprises the healing agent in the microcapsule and the polymerizing catalyst. (A) In areas where the damage occurs, cracks occur in the matrix. (B) It allows the opening of the microcapsules in the crack composite matrix and the healing agents in it spread throughout the crack. (C) The healing agents contact the catalyst which triggers the bonds that keep the cracked surfaces closed.
Fig. 10.2 shows that a structural composite that can completely heal itself is created. Polymerization kinetics in situ plays an essential role in determining the degree of repair. As a result of the data obtained, it is difficult to pass clear resins to structural (fiber-reinforced) composites. The catalytic triggers involved in the matrix of fiber-reinforced composites helped to overcome this difficulty by which recovery would be activated [58]. The role of the catalyst, which plays a vital role in self-healing, has been studied carefully. Therefore several modeling studies on the improvement of the catalyst concentration are known. The developed Grubbs catalyst was found to have three different morphologies [77]. Thermal stability is then used in the second-generation studies of Grubbs catalyst on self-healing composites [78]. However, when comparing first- and second-generation catalysts, it has been observed that the firstgeneration catalyst has priority because of its catalytic activity and tendency to be homogeneously dispersed [79]. The healing agents used for self-healing composite materials are of equal importance. Among these curative agents, dicyclopentadiene (DCPD) has two stereoisomers in a form which significantly affects the healing system [80]. When the
182
Self-Healing Composite Materials
reactive level of endo- and exo-isomers is examined, the exo-isomer is located on a more reactive level [81]. However, this situation has an adverse effect on the healing process due to the rapid release of the polymerization recovery agent [80]. In contrast to the exo-isomer, the endo-isomer has several advantages. These advantages are primarily commercially available, long shelf life, and low viscosity [80]. Mixing of 5-ethylidene-2-norbornene with DCPD results in a remediation process where faster hardening occurs and fewer catalysts are needed [82]. Both the concentration and the size of healing agents and catalyst are of importance in healing components [53]. Also, a hardness improvement of between 2% and 115% appears to occur, taking into account the concentration of the microcapsule and the initiator of the PDMS matrix [53]. The concentration of the curing agents and initiators is essential as well as the addition of dispersion and additives is one of the considerations in the process. Dispersion is essential to prevent the aggregation of microcapsules [83].
10.2.2 Remote self-healing Dispersed or degraded materials do not need healing microcapsules. Instead, a selfhealing repair can be carried out using a melt-inducible polymer provided locally. In this process, superparamagnetic γ-Fe2O3 nanoparticles embedded in the thermoplastic film are utilized [84]. The operating principle of the system is that the nanoparticles vibrating as a result of the application of a magnetic field increase the intermediate temperature of the polymer and activate the magnetic moment of the nanoparticles. In the next process, the local melting of the thermoplastic flowing into the fracture on the material is realized, and the healing process is provided (Fig. 10.3) [83,85]. There may be an improvement in self-healing processes by giving various stimuli for some substances. An example of this is the use of electric, electromagnetic, and infrared rays to provide local warming over the graphene plates. If graphene layers are incorporated into the polyurethane matrix, it can be self-healing by the effect of material stimuli and provides a tensile strength of 98% [86]. In another study, encapsulation and healing properties were combined with lightsensitive protective coatings [87 90]. For example, TiO2, which is extremely sensitive to light, is encapsulated into a corrosion-inhibitor, benzotriazole-coated polyelectrolyte shell. TiO2 is rapidly activated by ultraviolet (UV) [89]. A photocatalytic process is initiated on TiO2 by UV, and pH changes occur locally on the TiO2 surface. This change in pH triggers the release of the inhibitor. The inhibitor, encapsulated in polyelectrolyte, is free after the pH change [88]. Although activity is fast for TiO2, the wavelength of light is essential for releasing the healing agents in the capsule. This is evaluated according to the nanoparticle used. For example, UV light provides efficient heating for noble metal nanoparticles and leads to the idea of being used in self-healing materials [89]. Another example is the healing process obtained by a mixture of gold nanoparticles and zinc phthalocyanines. The obtained component exhibits the ability to improve under laser pulse radiation and enhances the area by combining the damaged area in the composite material [87].
Enhancements in self-curing composites
183
Figure 10.3 Crack in a polymer matrix healed via localized melting as superparamagnetic nanoparticles oscillate in a magnetic field. Image from V. Amendola, D. Dini, S. Polizzi, et al., Self-Healing of gold nanoparticles in thepresence of zinc phthalocyanines and their very efficient nonlinear absorptionperformances, J Phys Chem C 2009;113:8688 8695; Based on E.V. Skorb, A.G. Skirtach, D.V. Sviridov, et al., Laser-controllable coatings forcorrosion protection, ACS Nano 2009;3:1753 1760.
10.2.3 Shape memory assisted self-healing To achieve a healthy recovery in the composite material, the network in the crack region needs to be remodeled. The lining of the crack must be coated to ensure recovery. Filling of the break in the material entirely by the healing agents provides an improvement in the efficiency of the treatment [91]. Shape memory materials (SMMs) are involved in the recovery process. The SMMs have an initial shape and help to repair the original crack in the material after activation by the correct stimulus. SMMs combined with composite materials show a high improvement with curative agents [92]. The state of summarizing this process is shown in Fig. 10.4 [93]. There are many stimuli of SMMs that help maintain the originality of composite materials. These stimuli are temperature [94], magnet [95], electric [96], water [97], chemicals [98], and light [99]. SMMs are an area that needs to be studied, and they are functional at many points due to their unique features [100]. Various SMMs can be formed, and one of these is polyurethane composite SMMs with electroactive CNT support [101,102]. Components that are added to make composite materials self-healing can complicate these healing systems. However, the composite material obtained by welldesigned models can be converted into an effective product by providing various
184
Self-Healing Composite Materials
Figure 10.4 Illustration of SMM wires acting to close a crack [98].
properties. The SMMs used for self-healing materials give advantages to the material. SMMs can be either manually injected into the material [92] or embedded in the material matrix with the help of microcapsules. In this way, it helps the healing agents to repair the crack on the material more efficiently. However, in addition to these advantages, one concern is that it may cause an increase in the size of a crack that occurs as a result of misalignment of SMMs in the matrix [103]. Supporting additional materials to increase the efficiency of improvement can sometimes result in beneficial or harmful mechanical properties.
10.3
Self-healing composites: vascular networks
For the healing of wound area in biological systems, substances that help to clot in the damaged area should migrate to that region. The structure that is responsible for ensuring this is the circulatory system. In the human circulatory system, oxygen and nutrient transfer are carried out to feed the cells alongside the healing agents. The idea that these advantages provided by the circulatory system can also be applied to materials has been dominant. The concept of a carriage similar to the circulatory system has been used in the testing of a method that can heal itself in cement [85]. Several studies were then carried out to develop self-healing polymers [104]. Among the remediation systems, vascular networks are known as interconnected hollow webs, which enable materials to be self-healed, allowing the healing agents to be connected to a reservoir by hand. In a study by Pang et al., they looked at the effect of healing agents on the healing efficiency of the storage process in this system [105].
Enhancements in self-curing composites
185
Some vascular network formations can be provided by placing empty tubes into matrix materials [21,22,106]. Also, a network may be formed by using nonsacrificial materials in the nontubular vasculature. In this system, after the material formation is observed, the sacrificial material is removed, and the material is provided with an empty network system. The layer-by-layer technique can generate tubular microvascular networks for these and similar systems. Also, using the direct writing system [107], leakage ink networks are also generated in the plastic matrix [23].
10.3.1 Design considerations There should be sufficient pressure in the vascular network established in the material matrix to adequately distribute the curative agents [108]. Similar to this system, for example, vertebrate animals make it possible for blood to move along the vessels as a result of contraction of the heart muscle. Capillary forces can provide this fertilization without the need for a pump in regions with a dense network [109]. The curative agents in this system utilize diffusion to move to the site of the crack. The duty of external pumps in the system also has the task of guiding the flow of healing agents into the damaged area [110]. However, a computer system or human intervention is needed to perform such a cycle in a controlled manner. The resultant high pressure can improve the repair efficiency of the healing agents in the damaged area. The organization and architecture of vascular networks for composite materials are essential. Also, the mechanical properties imparted to the material are effective in the flow dynamics and the efficiency of self-healing in crack propagation [108]. The most important factor underlying the addition of support materials to composite materials is that they affect the mechanical properties of the additives on the material. However, it is very difficult to know the effects of the additive on the composite material. The effect of the additive depends on the material, the properties of the interface, the morphological feature, and the distribution of the materials. Varieties of vascular networks range from the simplest to the most complex network. That is, single-plane parallel hollow simple fiber [111] can be in complex structures similar to the tree-like appearance of the lungs [112]. As shown in Fig. 10.5, the sacrificial fibers used in this process can be evaporated in the composite material to provide a 3D vascular network system [23,113]. Informing these webs, the composite material has to be woven with the fibers along the composite layers. Esser-Kahn, working on the fibers, used sacrificial fibers from the polylactide for the composite material [33]. The highest recovery efficiency in the vascular network system was observed during the second and third time spontaneous recovery period compared to the first recovery period. Also, various studies on the architecture of vascular networks and the design of different network structures are needed. There are significant advantages and disadvantages to each designed network structure [114].
186
Self-Healing Composite Materials
Figure 10.5 (A) Diagram of a straight vascular system [110]; (B) Schematic of multibranched vascular network [111].
10.3.2 Scaling to bulk There are some potential complications required for bulk materials according to coatings [115]. There must be a pressure in the channels of the network system so that the flow of liquid is adequately maintained. For this to happen, a pump is needed. The vascular network system needs a fluid supply with a reservoir system. In this system, treatment agents are released against damage and the related damage area is repaired. However, to provide a continuous healing capability, the network should be associated with a continuous connection with a reservoir of curing agents. Also, the vascular system should have a sufficiently low viscosity inside and outside the network so that the healing agents can migrate through the system. However, this viscosity should vary depending on the temperature factor. Furthermore, there are successful applications of vacuum-assisted curative transfer molding vascular composites [116], and these designed self-healing composite materials are seen as promising materials.
10.4
Conclusion
In many industries, fiber-supported polymers are commonly preferred materials. Composite materials may be unintentionally damaged; therefore, repairing damaged areas can be achieved by providing a self-healing feature for undetectable damage of composite materials. To measure the healing ability of materials which can heal itself, “healing efficiency” can be obtained by looking at the ratio of the material to the original material and the amount of improved material. Improvement efficiency is not limited to this. In addition, it can be determined by looking at measurable
Enhancements in self-curing composites
187
material properties. The fact that 100% of the composite material can be seen at first glance can be seen as a great advantage, but its effect on the material should be considered. For example, if the material is deprived of its strength and hardness, it should not be used [117]. If we want to get harder, stronger, and smarter materials, we need to understand the existing materials. For this purpose, this chapter deals with self-healing materials in several examples.
References [1] Liu Q, Paavola J. Lightweight design of composite laminated structures with frequency constraint. Compos Struct 2016;156:356 60. [2] Azwa ZN, Yousif BF, Manalo AC, et al. A review on the degradability of polymeric composites based on natural fibres. Mater Des 2013;47:424 42. [3] Mittal G, Dhand V, Rhee KY, et al. A review on carbon nanotubes and graphene as fillers in reinforced polymer nanocomposites. J Ind Eng Chem 2015;21:11 25. [4] Dhand V, Mittal G, Rhee KY, et al. A short review on basalt fiber reinforced polymer composites. Compos Part B Eng 2015;73:166 80. [5] Hung P, Lau K, Cheng L, et al. Impact response of hybrid carbon/glass fibre reinforced polymer composites designed for engineering applications. Compos Part B Eng 2018;133:86 90. [6] AL-Oqla FM, Sapuan SM, Anwer T, et al. Natural fiber reinforced conductive polymer composites as functional materials: a review. Synth Met 2015;206:42 54. [7] Wu DY, Meure S, Solomon D. Self-healing polymeric materials: a review of recent developments. Prog Polym Sci 2008;33:479 522. [8] Li VC, Lim YM, Chan Y-W. Feasibility study of a passive smart self-healing cementitious composite. Compos Part B Eng 1998;29:819 27. [9] Hargou K, Pingkarawat K, Mouritz AP, et al. Ultrasonic activation of mendable polymer for self-healing carbon epoxy laminates. Compos Part B Eng 2013;45:1031 9. [10] Guadagno L, Longo P, Raimondo M, et al. Use of Hoveyda Grubbs’ second generation catalyst in self-healing epoxy mixtures. Compos Part B Eng 2011;42:296 301. [11] Urban MW. Stratification, stimuli-responsiveness, self-healing, and signaling in polymer networks. Prog Polym Sci 2009;34:679 87. [12] White SR, Sottos NR, Geubelle PH, et al. Autonomic healing of polymer composites. Nature 2001;409:794 7. [13] Brown EN, Kessler MR, Sottos NR, et al. In situ poly(urea-formaldehyde) microencapsulation of dicyclopentadiene. J Microencapsul 2003;20:719 30. [14] Yang J, Keller MW, Moore JS, et al. Microencapsulation of isocyanates for selfhealing polymers. Macromolecules 2008;41:9650 5. [15] Yuan L, Gu A, Liang G. Preparation and properties of poly(urea formaldehyde) microcapsules filled with epoxy resins. Mater Chem Phys 2008;110:417 25. [16] Yuan L, Liang G, Xie J, et al. Preparation and characterization of poly(urea-formaldehyde) microcapsules filled with epoxy resins. Polymer (Guildf) 2006;47:5338 49. [17] Yuan L, Liang G-Z, Xie J-Q, et al. The permeability and stability of microencapsulated epoxy resins. J Mater Sci 2007;42:4390 7. [18] Cosco S, Ambrogi V, Musto P, et al. Properties of poly(urea-formaldheyde) microcapsules containing an epoxy resin. J Appl Polym Sci 2007;105:1400 11.
188
Self-Healing Composite Materials
[19] Caruso MM, Delafuente DA, Ho V, et al. Solvent-promoted self-healing epoxy materials. Macromolecules 2007;40:8830 2. [20] Caruso MM, Blaiszik BJ, White SR, et al. Full recovery of fracture toughness using a nontoxic solvent-based self-healing system. Adv Funct Mater 2008;18:1898 904. [21] Bleay S, Loader C, Hawyes V, et al. A smart repair system for polymer matrix composites. Compos Part A Appl Sci Manuf 2001;32:1767 76. [22] Pang JWC, Bond IP. A hollow fibre reinforced polymer composite encompassing selfhealing and enhanced damage visibility. Compos Sci Technol 2005;65:1791 9. [23] Toohey KS, Sottos NR, Lewis JA, et al. Self-healing materials with microvascular networks. Nat Mater 2007;6:581 5. [24] Yuan YC, Rong MZ, Zhang MQ, et al. Self-healing polymeric materials using epoxy/ mercaptan as the healant. Macromolecules 2008;41:5197 202. [25] Belbekhouche S, Ali G, Dulong V, et al. Synthesis and characterization of thermosensitive and pH-sensitive block copolymers based on polyetheramine and pullulan with different length. Carbohydr Polym 2011;86:304 12. [26] Yu J, Yang Q-X. Magnetization improvement of Fe-pillared clay with application of polyetheramine. Appl Clay Sci 2010;48:185 90. [27] Tan S, Walus S, Gustafsson T, et al. 3-D microbattery electrolyte by self-assembly of oligomers. Solid State Ionics 2011;198:26 31. [28] Guan N, Xu J, Wang L, et al. One-step synthesis of amine-functionalized thermoresponsive magnetite nanoparticles and single-crystal hollow structures. Colloids Surfaces A Physicochem Eng Asp 2009;346:221 8. [29] Kondyurin A, Komar LA, Svistkov AL. Combinatory model of curing process in epoxy composite. Compos Part B Eng 2012;43:616 20. [30] McIlroy DA, Blaiszik BJ, Caruso MM, et al. Microencapsulation of a reactive liquidphase amine for self-healing epoxy composites. Macromolecules 2010;43:1855 9. [31] Yuan YC, Rong MZ, Zhang MQ. Preparation and characterization of microencapsulated polythiol. Polymer (Guildf) 2008;49:2531 41. [32] Minami H, Kanamori H, Hata Y, et al. Preparation of microcapsules containing a curing agent for epoxy resin by polyaddition reaction with the self-assembly of phaseseparated polymer method in an aqueous dispersed system. Langmuir 2008;24:9254 9. [33] Toohey KS, Hansen CJ, Lewis JA, et al. Delivery of two-part self-healing chemistry via microvascular networks. Adv Funct Mater 2009;19:1399 405. [34] Hansen CJ, Wu W, Toohey KS, et al. Self-healing materials with ınterpenetrating microvascular networks. Adv Mater 2009;21:4143 7. [35] Wu X-F, Rahman A, Zhou Z, et al. Electrospinning core-shell nanofibers for interfacial toughening and self-healing of carbon-fiber/epoxy composites. J Appl Polym Sci 2013;129:1383 93. [36] Coope TS, Wass DF, Trask RS, et al. Metal triflates as catalytic curing agents in selfhealing fibre reinforced polymer composite materials. Macromol Mater Eng 2014;299:208 18. [37] Patrick JF, Hart KR, Krull BP, et al. Continuous self-healing life cycle in vascularized structural composites. Adv Mater 2014;26:4302 8. [38] Sinha-Ray S, Pelot DD, Zhou ZP, et al. Encapsulation of self-healing materials by coelectrospinning, emulsion electrospinning, solution blowing and intercalation. J Mater Chem 2012;22:9138. [39] Wu X-F, Yarin AL. Recent progress in interfacial toughening and damage self-healing of polymer composites based on electrospun and solution-blown nanofibers: an overview. J Appl Polym Sci 2013;130:2225 37.
Enhancements in self-curing composites
189
[40] Lee MW, An S, Jo HS, et al. Self-healing nanofiber-reinforced polymer composites. 1. tensile testing and recovery of mechanical properties. ACS Appl Mater Interfaces 2015;7:19546 54. [41] Das A, Sallat A, Bo¨hme F, et al. Ionic modification turns commercial rubber into a self-healing material. ACS Appl Mater Interfaces 2015;7:20623 30. [42] Lee MW, An S, Jo HS, et al. Self-healing nanofiber-reinforced polymer composites. 2. Delamination/debonding and adhesive and cohesive properties. ACS Appl Mater Interfaces 2015;7:19555 61. [43] Lee MW, Yoon SS, Yarin AL. Solution-blown core shell self-healing nano- and microfibers. ACS Appl Mater Interfaces 2016;8:4955 62. [44] Lee MW, An S, Lee C, et al. Self-healing transparent core-shell nanofiber coatings for anti-corrosive protection. J Mater Chem A 2014;2:7045 53. [45] An S, Liou M, Song KY, et al. Highly flexible transparent self-healing composite based on electrospun core shell nanofibers produced by coaxial electrospinning for anticorrosion and electrical insulation. Nanoscale 2015;7:17778 85. [46] Cho SH, White SR, Braun PV. Self-healing polymer coatings. Adv Mater 2009;21:645 9. [47] Lee MW, Sett S, Yoon SS, et al. Fatigue of self-healing nanofiber-based composites: static test and subcritical crack propagation. ACS Appl Mater Interfaces 2016;8:18462 70. [48] Kessler M, Sottos N, White S. Self-healing structural composite materials. Compos Part A Appl Sci Manuf 2003;34:743 53. [49] Hillewaere XKD, Du Prez FE. Fifteen chemistries for autonomous external self-healing polymers and composites. Prog Polym Sci 2015;49 50:121 53. [50] Everitt DT, Luterbacher R, Coope TS, et al. Optimisation of epoxy blends for use in extrinsic self-healing fibre-reinforced composites. Polymer (Guildf) 2015;69 283 92. [51] Pandell NW, Temin SC. Application of reactants and/or catalysts to textile fabrics in microencapsulated form; 1972. [52] Bulbenko G, Sorg E, Gallagher J. One-part polythiol compositions containing encapsulated activators; 1973. [53] Wolinski LE. Thermoplastic polyurethane resin dissolved in an acrylic monomer plus an additional acrylic monomer, free radical catalyst; 1978. [54] Garcı´a SJ, Fischer HR, van der Zwaag S. A critical appraisal of the potential of self healing polymeric coatings. Prog Org Coatings 2011;72:211 21. [55] Li GL, Zheng Z, Mo¨hwald H, et al. Silica/polymer double-walled hybrid nanotubes: synthesis and application as stimuli-responsive nanocontainers in self-healing coatings. ACS Nano 2013;7:2470 8. [56] Dry C. Procedures developed for self-repair of polymer matrix composite materials. Compos Struct 1996;35:263 9. [57] Motuku M, Vaidya UK, Janowski GM. Parametric studies on self-repairing approaches for resin infused composites subjected to low velocity impact. Smart Mater Struct 1999;8:623 38. [58] Bond IP, Trask RS, Williams HR, et al. Self healing fibre-reinforced polymer composites: an overview. Self healing materials. Dordrecht: Springer; 2007. p. 115 38. [59] Iijima S. Helical microtubules of graphitic carbon. Nature 1991;354:56 8. [60] Coleman JN, Khan U, Blau WJ, et al. Small but strong: a review of the mechanical properties of carbon nanotube polymer composites. Carbon N Y 2006;44 1624 52.
190
Self-Healing Composite Materials
[61] Wu AS, Coppola AM, Sinnott MJ, et al. Sensing of damage and healing in threedimensional braided composites with vascular channels. Compos Sci Technol 2012;72:1618 26. [62] Qian D, Wagner GJ, Liu WK, et al. Mechanics of carbon nanotubes. Appl Mech Rev 2002;55:495. [63] Troya D, Mielke SL, Schatz GC. Carbon nanotube fracture differences between quantum mechanical mechanisms and those of empirical potentials. Chem Phys Lett 2003;382:133 41. [64] Ba¸skaya G, Yıldız Y, Savk A, et al. Rapid, sensitive, and reusable detection of glucose by highly monodisperse nickel nanoparticles decorated functionalized multi-walled carbon nanotubes. Biosens Bioelectron 2017;91:728 33. [65] Sen ¸ B, Kuzu S, Demir E, et al. Highly monodisperse RuCo nanoparticles decorated on functionalized multiwalled carbon nanotube with the highest observed catalytic activity in the dehydrogenation of dimethylamine 2 borane. Int J Hydrogen Energy 2017;42:23292 8. [66] Ulus R, Yıldız Y, Eri¸s S, et al. Functionalized multi-walled carbon nanotubes (fMWCNT) as highly efficient and reusable heterogeneous catalysts for the synthesis of acridinedione derivatives. ChemistrySelect 2016;1:3861 5. [67] Yıldız Y, Esirden ˙I, Erken E, et al. Microwave (Mw)-assisted synthesis of 5-substituted 1H-Tetrazoles via [3 1 2] cycloaddition catalyzed by Mw-Pd/Co nanoparticles decorated on multi-walled carbon nanotubes. ChemistrySelect 2016;1:1695 701. [68] C ¸ elik B, Kuzu S, Erken E, et al. Nearly monodisperse carbon nanotube furnished nanocatalysts as highly efficient and reusable catalyst for dehydrocoupling of DMAB and C1 to C3 alcohol oxidation. Int J Hydrogen Energy 2016;41:3093 101. [69] Sen S, Sen F, Boghossian AA, et al. Effect of reductive dithiothreitol and trolox on nitric oxide quenching of single-walled carbon nanotubes. J Phys Chem C 2013;117:593 602. [70] Sen F, Boghossian AA, Sen S, et al. Observation of oscillatory surface reactions of riboflavin, trolox, and singlet oxygen using single carbon nanotube fluorescence spectroscopy. ACS Nano 2012;6:10632 45. [71] Zhang J, Landry MP, Barone PW, et al. Molecular recognition using corona phase complexes made of synthetic polymers adsorbed on carbon nanotubes. Nat Nanotechnol 2013;8:959 68. [72] Iverson NM, Barone PW, Shandell M, et al. In vivo biosensing via tissue-localizable near-infrared-fluorescent single-walled carbon nanotubes. Nat Nanotechnol 2013;8:873 80. [73] Ulissi ZW, Sen F, Gong X, et al. Spatiotemporal intracellular nitric oxide signaling captured using internalized, near-infrared fluorescent carbon nanotube nanosensors. Nano Lett 2014;14:4887 94. [74] Bass R. Synthesis and characterization of self-healing poly (carbonate urethane) carbon-nanotube composites, ,https://scholarcommons.usf.edu/etd/2999.; 2011 [accessed 08.01.19]. [75] Kope´c M, Szczepanowicz K, Mordarski G, et al. Self-healing epoxy coatings loaded with inhibitor-containing polyelectrolyte nanocapsules. Prog Org Coatings 2015;84:97 106. [76] Brown EN, Sottos NR, White SR. Fracture testing of a self-healing polymer composite. Exp Mech 2002;42:372 9. [77] Jones AS, Rule JD, Moore JS, et al. Catalyst morphology and dissolution kinetics of self-healing polymers. Chem Mater 2006;18:1312 17.
Enhancements in self-curing composites
191
[78] Wilson GO, Caruso MM, Reimer NT, et al. Evaluation of ruthenium catalysts for ringopening metathesis polymerization-based self-healing applications. Chem Mater 2008;20:3288 97. [79] Liu X, Sheng X, Lee JK, et al. Rheokinetic evaluation of self-healing agents polymerized by Grubbs catalyst embedded in various thermosetting systems. Compos Sci Technol 2009;69:2102 7. [80] Mauldin TC, Rule JD, Sottos NR, et al. Self-healing kinetics and the stereoisomers of dicyclopentadiene. J R Soc Interface 2007;4:389 93. [81] Rule JD, Moore JS. ROMP reactivity of endo- and exo-dicyclopentadiene. Macromolecules 2002;35:7878 82. [82] Liu X, Lee JK, Yoon SH, et al. Characterization of diene monomers as healing agents for autonomic damage repair. J Appl Polym Sci 2006;101:1266 72. [83] Zheludkevich ML, Shchukin DG, Yasakau KA, et al. Anticorrosion coatings with selfhealing effect based on nanocontainers impregnated with corrosion inhibitor. Chem Mater 2007;19:402 11. [84] Corten CC, Urban MW. Repairing polymers using oscillating magnetic field. Adv Mater 2009;21:5011 15. [85] Yang Y, Urban MW. Self-healing polymeric materials. Chem Soc Rev 2013;42:7446 67. [86] Huang L, Yi N, Wu Y, et al. Multichannel and repeatable self-healing of mechanical enhanced graphene-thermoplastic polyurethane composites. Adv Mater 2013;25:2224 8. [87] Amendola V, Dini D, Polizzi S, et al. Self-Healing of gold nanoparticles in the presence of zinc phthalocyanines and their very efficient nonlinear absorption performances. J Phys Chem C 2009;113:8688 95. [88] Skorb EV, Skirtach AG, Sviridov DV, et al. Laser-controllable coatings for corrosion protection. ACS Nano 2009;3:1753 60. [89] Skorb EV, Sviridov DV, Mo¨hwald H, et al. Light responsive protective coatings. Chem Commun 2009;0:6041 3. [90] Cortie MB, McDonagh AM. Synthesis and optical properties of hybrid and alloy plasmonic nanoparticles. Chem Rev 2011;111:3713 35. [91] Rule JD, Sottos NR, White SR. Effect of microcapsule size on the performance of selfhealing polymers. Polymer (Guildf) 2007;48:3520 9. [92] Kirkby EL, Michaud VJ, Ma˚nson JAE, et al. Performance of self-healing epoxy with microencapsulated healing agent and shape memory alloy wires. Polymer (Guildf) 2009;50:5533 8. [93] Kirkby EL, Rule JD, Michaud VJ, et al. Embedded shape-memory alloy wires for ımproved performance of self-healing polymers. Adv Funct Mater 2008;18:2253 60. [94] Luo X, Mather PT. Shape memory assisted self-healing coating. ACS Macro Lett 2013;2:152 6. [95] de Lange RG, Zijderveld JA. Shape-memory effect and the martensitic transformation of TiNi. J Appl Phys 1968;39:2195 200. [96] Sato A, Yamaji Y, Mori T. Physical properties controlling shape memory effect in FeMn-Si alloys. Acta Metall 1986;34:287 94. [97] Bar-Cohen Y. Electroactive polymers as artificial muscles: capabilities, potentials and challenges. Robotics. Reston, VA: American Society of Civil Engineers; 2000. p. 188 96. [98] Huang WM, Yang B, An L, et al. Water-driven programmable polyurethane shape memory polymer: demonstration and mechanism. Appl Phys Lett 2005;86:114105.
192
Self-Healing Composite Materials
[99] Lv H, Leng J, Liu Y, et al. Shape-memory polymer in response to solution. Adv Eng Mater 2008;10:592 5. [100] Lendlein A, Jiang H, Ju¨nger O, et al. Light-induced shape-memory polymers. Nature 2005;434:879 82. [101] Cho JW, Kim JW, Jung YC, et al. Electroactive shape-memory polyurethane composites ıncorporating carbon nanotubes. Macromol Rapid Commun 2005;26:412 16. [102] Li G, John M. A self-healing smart syntactic foam under multiple impacts. Compos Sci Technol 2008;68:3337 43. [103] Xu W, Li G. Constitutive modeling of shape memory polymer based self-healing syntactic foam. Int J Solids Struct 2010;47:1306 16. [104] Lanzara G, Yoon Y, Liu H, et al. Carbon nanotube reservoirs for self-healing materials. Nanotechnology 2009;20:335704 12. [105] Dry C. Matrix cracking repair and filling using active and passive modes for smart timed release of chemicals from fibers into cement matrices. Smart Mater Struct 1994;3:118 23. [106] Pang JWC, Bond IP. ‘Bleeding composites’—damage detection and self-repair using a biomimetic approach. Compos Part A Appl Sci Manuf 2005;36:183 8. [107] Therriault D, White SR, Lewis JA. Chaotic mixing in three-dimensional microvascular networks fabricated by direct-write assembly. Nat Mater 2003;2:265 71. [108] Norris CJ, Meadway GJ, O’Sullivan MJ, et al. Self-healing fibre reinforced composites via a bioinspired vasculature. Adv Funct Mater 2011;21:3624 33. [109] Hamilton AR, Sottos NR, White SR. Self-healing of ınternal damage in synthetic vascular materials. Adv Mater 2010;22:5159 63. [110] Williams HR, Trask RS, Bond IP. Self-healing sandwich panels: restoration of compressive strength after impact. Compos Sci Technol 2008;68:3171 7. [111] Williams HR, Trask RS, Bond IP. Self-healing composite sandwich structures. Smart Mater Struct 2007;16:1198 207. [112] Kim S, Lorente S, Bejan A. Vascularized materials: tree-shaped flow architectures matched canopy to canopy. J Appl Phys 2006;100:063525 33. [113] Esser-Kahn AP, Thakre PR, Dong H, et al. Three-dimensional microvascular fiberreinforced composites. Adv Mater 2011;23:3654 8. [114] Norris CJ, Bond IP, Trask RS. The role of embedded bioinspired vasculature on damage formation in self-healing carbon fibre reinforced composites. Compos Part A Appl Sci Manuf 2011;42:639 48. [115] Williams H, Trask R, Knights A, et al. Biomimetic reliability strategies for selfhealing vascular networks in engineering materials. J R Soc Interface 2008;5:735 47. [116] Koralagundi Matt AK, Strong S, ElGammal T, et al. Development of novel selfhealing polymer composites for use in wind turbine blades. J Energy Resour Technol 2015;137:051202 7. [117] Scheiner M, Dickens TJ, Okoli O. Progress towards self-healing polymers for composite structural applications. Polymer (Guildf) 2016;83:260 82.
10
Hakan Burhan, Suna Saygili and Fatih Sen ¸ Sen Research Group, Department of Biochemistry, Dumlupınar University, Ku¨tahya, Turkey
10.1
Introduction
A lot of research has been done to facilitate human life throughout the history of humankind, and most of them have been successful. Nowadays, thanks to the rapid advancement of technology, the needs of many smart and new materials have increased, and it has become more functional by developing existing products. Polymeric materials can be used as an example for meeting these needs. Polymeric materials are preferred in many areas due to their light, inexpensive, and easyprocessing properties compared to metal and ceramic products among traditional materials [1]. In addition to the properties of the polymers, their corrosion stability and good metallic properties are present. However, the presence of environmental stability, as well as low conductivity, chemical and thermal stability are among the disadvantages of polymers [2]. The polymer composite products to be obtained in order to get rid of the disadvantages of the polymers have been used in order to improve their matrices by getting help from a wide variety of filling materials. In order to increase the performance required in the present products, there is the possibility of being supplemented by many fillers (particles, fibers or platelets, synthetic or natural, organic or inorganic) regardless of the scale of the polymer matrix (macro, micro, or nano) [3 6]. The presence of self-healing materials and their development is seen as an area of great interest as it will significantly facilitate human life [7 11]. The basic principle of these materials is the encapsulation of healing agents in the matrix of materials that can be broken or cracked. When any cracking or cracking on the material results in the destruction of the capsule of the crack-improving agent, the scavenging agents spread along the crack and bind the resulting gap [12]. Thanks to this feature, as it is seen that self-healing materials can be produced in various fields and applications. In the preparation of self-healing materials, when used in the literature, it is observed that they are curative agents such as polydimethylsiloxane (PDMS), dicyclopentadiene, and epoxy [13 21]. However, epoxies among these therapeutic agents have not yet been produced in any material [22 25]. The reason for this Self-Healing Composite Materials. DOI: https://doi.org/10.1016/B978-0-12-817354-1.00010-7 © 2020 Elsevier Inc. All rights reserved.
178
Self-Healing Composite Materials
failure is that it is due to the problems of microencapsulation of hardeners suitable for epoxy curing [26]. Amine-type curing agents are traditionally used for the curing of the epoxy, and they have a very active feature at room temperature. Therefore it is not possible to encapsulate epoxy in water or organic solvents [27 30]. Information on the encapsulation of curing agents is relatively low in the literature. Among these data, it was observed that several researchers tried to develop self-healing materials by using the in situ technique. Informing this process, monomers and enhancers were added to the water and agitated to prepare encapsulated curative agents [26,30 32]. However, due to the difficulty in maintaining the system pH and the lack of polymerization of the monomers, shell materials were used in the final applications. The spontaneous recovery that occurs on living things can be complicated or leave an interesting effect [12]. We can see that other damage can repair itself unless the damage is very severe or vital in the organ. For example, cracks or fractures in a scratch or bone that occur on the skin can be repaired and regained itself. This system of healing is known as a vascular system in mammals. Blood flow is observed as a result of a scratch on the human skin. Hemorrhage helps to transport the healing area to the wound site using blood vessels. The process that started here is repaired by a system that works quickly, such as stopping the bleeding in the wound area, failure to progress, and a shell on the wound. This spontaneous healing process in living things has encouraged a variety of studies to be done for engineering materials [23,33 35]. Micro- and macro-nanofibrils or tubes which function the same when compared to the mammalian blood vessels produce materials that can recover spontaneously. With the help of nanofibrils, healing agents transmitted through blood vessels, epoxy resin, resin monomers, and hardeners can also be delivered in engineering materials. The healing agents stored in the matrix of the materials in the encapsulated state are released, polymerized, or solidified by cracks resulting from damage. In this way, broken fiber ends are combined [33,35 37]. If the damage to the material triggers a condition related to crack propagation, the self-healing process can prevent crack growth without being irreversible. Propagation of particular cracks on composite materials is useful in decomposition of composites. Most composite materials are highly vulnerable to these cracks [35,38,39]. It is difficult to correct these damages as well as detect this crack on the composite. The formation of a small crack on the composite material may cause the entire structure to deteriorate over time. In the areas where these materials are used, support or replacement materials should be placed for security purposes by considering these risks. The self-healing system is very important in eliminating damage such as flexures [33,35], stresses [40,41], and delamination of composite materials [42,43]. The healing agents can entirely or partially recover the hardness factor of the material in the damaged area. In addition to this, corrosion protection of the materials is ensured using anticorrosion coatings in order to solve the corrosion problems of materials and self-healing is achieved [44 46]. Some studies may be done before.
Enhancements in self-curing composites
179
It has been observed that the previously drawn cracks of the materials exposed to static stress can self-heal [47].
10.2
Self-healing composites: dispersed agents
A wound that occurs in the skin of mammals is repaired by the spontaneous healing feature of the organism. The blood stopper and coagulating agents in the circulatory system of life are the role models for the engineering materials to be repaired in this way. The self-healing agents can be especially liquid and solid. As seen in Fig. 10.1, the different components (A) may be in the form of a manual material crack, (B) in the material matrix, or (C) in the form of a combination of coupling and injection [48]. It is observed that the recovery efficiency in the epoxy material system for selfhealing varies according to the method of use [48]. This change can be between 38% and 99%, as well as an improvement of up to 119% due to epoxy chemistry [49,50].
10.2.1 Encapsulation The capturing of catalysts in microcapsules or cross-linking reactants developed has been studied [51]. However, expansion studies have been followed to have the
Figure 10.1 Three methods of inclusion for the healing agents and catalyst in a composite: (A) injection; (B) incorporation; (C) a combination of injection & incorporation [51].
180
Self-Healing Composite Materials
ingredients required for polymer coatings in capsule formation [52]. When these microcapsules were found to be broken under a light pressure on them, it was inevitable to use them in the textile industry in 1978 [53]. Later, as a result of making the curing agents into a capsule and being able to participate in other materials, it has paved the way for its use in biographical wound healing. Furthermore, self-healing and protective materials are now being developed on composite materials [54]. The encapsulation of the curative agents can be achieved by using hollow fibers, nanotubes [55], or microspheres [56]. Some discussions between these types of encapsulation have been inevitable, and the concentrations and dispersions of the catalysts and curing agents used for this process have also been discussed. A hollow fiber material was designed in the matrix to provide self-repairable feature between the composite materials. Another example of self-recovering polymer materials is the hollow glass pipette tubes which are contain the cyanoacrylate resin [57]. On the other hand, other materials could be used as hollow fibers or capillaries [21]. It is more preferred than capillaries such as copper and aluminum because of the easier breakability of the existing glass capillaries. The easy breaking of the glass capillary makes it easier for the resin to flow into the crack. The material required for another self-healing recovery is the nanotubes. Carbon nanotubes (CNTs) [58] are widely preferred for their many properties. Its main characteristics are its impressive mechanical properties for polymer strengths and additional resistance potentials [59]. Also, electrical resistance based detection [60] features are used. The origin of composite materials is already known to contain CNT. This provides information that CNTs can heal themselves [61]. The use of CNTs in a curative system can only work if they are injected into the CNTs and the CNTs are ruptured to release the encapsulated enhancement agents. Studies on CNTs have shown a high degree of success in their work [62]; however, they are not used as reservoirs in addition to their use as reinforcements [63]. The questioning of the healing properties of CNTs [64 73] is that they are very strong and will not tear. Besides, the concerns about nanotubes are due to their small diameters and resin viscosity. However, the above situation is not the case for SiO2polymeric hybrid nanotubes [74]. Polyelectrolyte nanocapsules [75] are therefore recommended for anticorrosion coatings. A new polymer has been developed in recent studies on self-healing [12]. Due to the microcapsules in the matrix, the life of the polymeric components is increased. It promises that any microcracks that may occur on the composite materials can be improved autonomously and that the life span can be significantly extended. Fig. 10.2 illustrates the concept of microcapsules. As a result of a crack on the material, the healing process takes place using microcapsules in an epoxy matrix. The curing agents contained in these capsules include the catalytic chemical trigger, allowing the crack to close. Cracking on the composite material leads to the explosion of microcapsules with curative agents through capillary action. The resulting therapeutic agents contact the broken surfaces in contact with the catalyst embedded in the material and initiate the coupling. Thanks to the microcapsules, as the self-healing of the material can be 90% [76].
Enhancements in self-curing composites
181
Figure 10.2 Spontaneous recovery [73]. The composite matrix comprises the healing agent in the microcapsule and the polymerizing catalyst. (A) In areas where the damage occurs, cracks occur in the matrix. (B) It allows the opening of the microcapsules in the crack composite matrix and the healing agents in it spread throughout the crack. (C) The healing agents contact the catalyst which triggers the bonds that keep the cracked surfaces closed.
Fig. 10.2 shows that a structural composite that can completely heal itself is created. Polymerization kinetics in situ plays an essential role in determining the degree of repair. As a result of the data obtained, it is difficult to pass clear resins to structural (fiber-reinforced) composites. The catalytic triggers involved in the matrix of fiber-reinforced composites helped to overcome this difficulty by which recovery would be activated [58]. The role of the catalyst, which plays a vital role in self-healing, has been studied carefully. Therefore several modeling studies on the improvement of the catalyst concentration are known. The developed Grubbs catalyst was found to have three different morphologies [77]. Thermal stability is then used in the second-generation studies of Grubbs catalyst on self-healing composites [78]. However, when comparing first- and second-generation catalysts, it has been observed that the firstgeneration catalyst has priority because of its catalytic activity and tendency to be homogeneously dispersed [79]. The healing agents used for self-healing composite materials are of equal importance. Among these curative agents, dicyclopentadiene (DCPD) has two stereoisomers in a form which significantly affects the healing system [80]. When the
182
Self-Healing Composite Materials
reactive level of endo- and exo-isomers is examined, the exo-isomer is located on a more reactive level [81]. However, this situation has an adverse effect on the healing process due to the rapid release of the polymerization recovery agent [80]. In contrast to the exo-isomer, the endo-isomer has several advantages. These advantages are primarily commercially available, long shelf life, and low viscosity [80]. Mixing of 5-ethylidene-2-norbornene with DCPD results in a remediation process where faster hardening occurs and fewer catalysts are needed [82]. Both the concentration and the size of healing agents and catalyst are of importance in healing components [53]. Also, a hardness improvement of between 2% and 115% appears to occur, taking into account the concentration of the microcapsule and the initiator of the PDMS matrix [53]. The concentration of the curing agents and initiators is essential as well as the addition of dispersion and additives is one of the considerations in the process. Dispersion is essential to prevent the aggregation of microcapsules [83].
10.2.2 Remote self-healing Dispersed or degraded materials do not need healing microcapsules. Instead, a selfhealing repair can be carried out using a melt-inducible polymer provided locally. In this process, superparamagnetic γ-Fe2O3 nanoparticles embedded in the thermoplastic film are utilized [84]. The operating principle of the system is that the nanoparticles vibrating as a result of the application of a magnetic field increase the intermediate temperature of the polymer and activate the magnetic moment of the nanoparticles. In the next process, the local melting of the thermoplastic flowing into the fracture on the material is realized, and the healing process is provided (Fig. 10.3) [83,85]. There may be an improvement in self-healing processes by giving various stimuli for some substances. An example of this is the use of electric, electromagnetic, and infrared rays to provide local warming over the graphene plates. If graphene layers are incorporated into the polyurethane matrix, it can be self-healing by the effect of material stimuli and provides a tensile strength of 98% [86]. In another study, encapsulation and healing properties were combined with lightsensitive protective coatings [87 90]. For example, TiO2, which is extremely sensitive to light, is encapsulated into a corrosion-inhibitor, benzotriazole-coated polyelectrolyte shell. TiO2 is rapidly activated by ultraviolet (UV) [89]. A photocatalytic process is initiated on TiO2 by UV, and pH changes occur locally on the TiO2 surface. This change in pH triggers the release of the inhibitor. The inhibitor, encapsulated in polyelectrolyte, is free after the pH change [88]. Although activity is fast for TiO2, the wavelength of light is essential for releasing the healing agents in the capsule. This is evaluated according to the nanoparticle used. For example, UV light provides efficient heating for noble metal nanoparticles and leads to the idea of being used in self-healing materials [89]. Another example is the healing process obtained by a mixture of gold nanoparticles and zinc phthalocyanines. The obtained component exhibits the ability to improve under laser pulse radiation and enhances the area by combining the damaged area in the composite material [87].
Enhancements in self-curing composites
183
Figure 10.3 Crack in a polymer matrix healed via localized melting as superparamagnetic nanoparticles oscillate in a magnetic field. Image from V. Amendola, D. Dini, S. Polizzi, et al., Self-Healing of gold nanoparticles in thepresence of zinc phthalocyanines and their very efficient nonlinear absorptionperformances, J Phys Chem C 2009;113:8688 8695; Based on E.V. Skorb, A.G. Skirtach, D.V. Sviridov, et al., Laser-controllable coatings forcorrosion protection, ACS Nano 2009;3:1753 1760.
10.2.3 Shape memory assisted self-healing To achieve a healthy recovery in the composite material, the network in the crack region needs to be remodeled. The lining of the crack must be coated to ensure recovery. Filling of the break in the material entirely by the healing agents provides an improvement in the efficiency of the treatment [91]. Shape memory materials (SMMs) are involved in the recovery process. The SMMs have an initial shape and help to repair the original crack in the material after activation by the correct stimulus. SMMs combined with composite materials show a high improvement with curative agents [92]. The state of summarizing this process is shown in Fig. 10.4 [93]. There are many stimuli of SMMs that help maintain the originality of composite materials. These stimuli are temperature [94], magnet [95], electric [96], water [97], chemicals [98], and light [99]. SMMs are an area that needs to be studied, and they are functional at many points due to their unique features [100]. Various SMMs can be formed, and one of these is polyurethane composite SMMs with electroactive CNT support [101,102]. Components that are added to make composite materials self-healing can complicate these healing systems. However, the composite material obtained by welldesigned models can be converted into an effective product by providing various
184
Self-Healing Composite Materials
Figure 10.4 Illustration of SMM wires acting to close a crack [98].
properties. The SMMs used for self-healing materials give advantages to the material. SMMs can be either manually injected into the material [92] or embedded in the material matrix with the help of microcapsules. In this way, it helps the healing agents to repair the crack on the material more efficiently. However, in addition to these advantages, one concern is that it may cause an increase in the size of a crack that occurs as a result of misalignment of SMMs in the matrix [103]. Supporting additional materials to increase the efficiency of improvement can sometimes result in beneficial or harmful mechanical properties.
10.3
Self-healing composites: vascular networks
For the healing of wound area in biological systems, substances that help to clot in the damaged area should migrate to that region. The structure that is responsible for ensuring this is the circulatory system. In the human circulatory system, oxygen and nutrient transfer are carried out to feed the cells alongside the healing agents. The idea that these advantages provided by the circulatory system can also be applied to materials has been dominant. The concept of a carriage similar to the circulatory system has been used in the testing of a method that can heal itself in cement [85]. Several studies were then carried out to develop self-healing polymers [104]. Among the remediation systems, vascular networks are known as interconnected hollow webs, which enable materials to be self-healed, allowing the healing agents to be connected to a reservoir by hand. In a study by Pang et al., they looked at the effect of healing agents on the healing efficiency of the storage process in this system [105].
Enhancements in self-curing composites
185
Some vascular network formations can be provided by placing empty tubes into matrix materials [21,22,106]. Also, a network may be formed by using nonsacrificial materials in the nontubular vasculature. In this system, after the material formation is observed, the sacrificial material is removed, and the material is provided with an empty network system. The layer-by-layer technique can generate tubular microvascular networks for these and similar systems. Also, using the direct writing system [107], leakage ink networks are also generated in the plastic matrix [23].
10.3.1 Design considerations There should be sufficient pressure in the vascular network established in the material matrix to adequately distribute the curative agents [108]. Similar to this system, for example, vertebrate animals make it possible for blood to move along the vessels as a result of contraction of the heart muscle. Capillary forces can provide this fertilization without the need for a pump in regions with a dense network [109]. The curative agents in this system utilize diffusion to move to the site of the crack. The duty of external pumps in the system also has the task of guiding the flow of healing agents into the damaged area [110]. However, a computer system or human intervention is needed to perform such a cycle in a controlled manner. The resultant high pressure can improve the repair efficiency of the healing agents in the damaged area. The organization and architecture of vascular networks for composite materials are essential. Also, the mechanical properties imparted to the material are effective in the flow dynamics and the efficiency of self-healing in crack propagation [108]. The most important factor underlying the addition of support materials to composite materials is that they affect the mechanical properties of the additives on the material. However, it is very difficult to know the effects of the additive on the composite material. The effect of the additive depends on the material, the properties of the interface, the morphological feature, and the distribution of the materials. Varieties of vascular networks range from the simplest to the most complex network. That is, single-plane parallel hollow simple fiber [111] can be in complex structures similar to the tree-like appearance of the lungs [112]. As shown in Fig. 10.5, the sacrificial fibers used in this process can be evaporated in the composite material to provide a 3D vascular network system [23,113]. Informing these webs, the composite material has to be woven with the fibers along the composite layers. Esser-Kahn, working on the fibers, used sacrificial fibers from the polylactide for the composite material [33]. The highest recovery efficiency in the vascular network system was observed during the second and third time spontaneous recovery period compared to the first recovery period. Also, various studies on the architecture of vascular networks and the design of different network structures are needed. There are significant advantages and disadvantages to each designed network structure [114].
186
Self-Healing Composite Materials
Figure 10.5 (A) Diagram of a straight vascular system [110]; (B) Schematic of multibranched vascular network [111].
10.3.2 Scaling to bulk There are some potential complications required for bulk materials according to coatings [115]. There must be a pressure in the channels of the network system so that the flow of liquid is adequately maintained. For this to happen, a pump is needed. The vascular network system needs a fluid supply with a reservoir system. In this system, treatment agents are released against damage and the related damage area is repaired. However, to provide a continuous healing capability, the network should be associated with a continuous connection with a reservoir of curing agents. Also, the vascular system should have a sufficiently low viscosity inside and outside the network so that the healing agents can migrate through the system. However, this viscosity should vary depending on the temperature factor. Furthermore, there are successful applications of vacuum-assisted curative transfer molding vascular composites [116], and these designed self-healing composite materials are seen as promising materials.
10.4
Conclusion
In many industries, fiber-supported polymers are commonly preferred materials. Composite materials may be unintentionally damaged; therefore, repairing damaged areas can be achieved by providing a self-healing feature for undetectable damage of composite materials. To measure the healing ability of materials which can heal itself, “healing efficiency” can be obtained by looking at the ratio of the material to the original material and the amount of improved material. Improvement efficiency is not limited to this. In addition, it can be determined by looking at measurable
Enhancements in self-curing composites
187
material properties. The fact that 100% of the composite material can be seen at first glance can be seen as a great advantage, but its effect on the material should be considered. For example, if the material is deprived of its strength and hardness, it should not be used [117]. If we want to get harder, stronger, and smarter materials, we need to understand the existing materials. For this purpose, this chapter deals with self-healing materials in several examples.
References [1] Liu Q, Paavola J. Lightweight design of composite laminated structures with frequency constraint. Compos Struct 2016;156:356 60. [2] Azwa ZN, Yousif BF, Manalo AC, et al. A review on the degradability of polymeric composites based on natural fibres. Mater Des 2013;47:424 42. [3] Mittal G, Dhand V, Rhee KY, et al. A review on carbon nanotubes and graphene as fillers in reinforced polymer nanocomposites. J Ind Eng Chem 2015;21:11 25. [4] Dhand V, Mittal G, Rhee KY, et al. A short review on basalt fiber reinforced polymer composites. Compos Part B Eng 2015;73:166 80. [5] Hung P, Lau K, Cheng L, et al. Impact response of hybrid carbon/glass fibre reinforced polymer composites designed for engineering applications. Compos Part B Eng 2018;133:86 90. [6] AL-Oqla FM, Sapuan SM, Anwer T, et al. Natural fiber reinforced conductive polymer composites as functional materials: a review. Synth Met 2015;206:42 54. [7] Wu DY, Meure S, Solomon D. Self-healing polymeric materials: a review of recent developments. Prog Polym Sci 2008;33:479 522. [8] Li VC, Lim YM, Chan Y-W. Feasibility study of a passive smart self-healing cementitious composite. Compos Part B Eng 1998;29:819 27. [9] Hargou K, Pingkarawat K, Mouritz AP, et al. Ultrasonic activation of mendable polymer for self-healing carbon epoxy laminates. Compos Part B Eng 2013;45:1031 9. [10] Guadagno L, Longo P, Raimondo M, et al. Use of Hoveyda Grubbs’ second generation catalyst in self-healing epoxy mixtures. Compos Part B Eng 2011;42:296 301. [11] Urban MW. Stratification, stimuli-responsiveness, self-healing, and signaling in polymer networks. Prog Polym Sci 2009;34:679 87. [12] White SR, Sottos NR, Geubelle PH, et al. Autonomic healing of polymer composites. Nature 2001;409:794 7. [13] Brown EN, Kessler MR, Sottos NR, et al. In situ poly(urea-formaldehyde) microencapsulation of dicyclopentadiene. J Microencapsul 2003;20:719 30. [14] Yang J, Keller MW, Moore JS, et al. Microencapsulation of isocyanates for selfhealing polymers. Macromolecules 2008;41:9650 5. [15] Yuan L, Gu A, Liang G. Preparation and properties of poly(urea formaldehyde) microcapsules filled with epoxy resins. Mater Chem Phys 2008;110:417 25. [16] Yuan L, Liang G, Xie J, et al. Preparation and characterization of poly(urea-formaldehyde) microcapsules filled with epoxy resins. Polymer (Guildf) 2006;47:5338 49. [17] Yuan L, Liang G-Z, Xie J-Q, et al. The permeability and stability of microencapsulated epoxy resins. J Mater Sci 2007;42:4390 7. [18] Cosco S, Ambrogi V, Musto P, et al. Properties of poly(urea-formaldheyde) microcapsules containing an epoxy resin. J Appl Polym Sci 2007;105:1400 11.
188
Self-Healing Composite Materials
[19] Caruso MM, Delafuente DA, Ho V, et al. Solvent-promoted self-healing epoxy materials. Macromolecules 2007;40:8830 2. [20] Caruso MM, Blaiszik BJ, White SR, et al. Full recovery of fracture toughness using a nontoxic solvent-based self-healing system. Adv Funct Mater 2008;18:1898 904. [21] Bleay S, Loader C, Hawyes V, et al. A smart repair system for polymer matrix composites. Compos Part A Appl Sci Manuf 2001;32:1767 76. [22] Pang JWC, Bond IP. A hollow fibre reinforced polymer composite encompassing selfhealing and enhanced damage visibility. Compos Sci Technol 2005;65:1791 9. [23] Toohey KS, Sottos NR, Lewis JA, et al. Self-healing materials with microvascular networks. Nat Mater 2007;6:581 5. [24] Yuan YC, Rong MZ, Zhang MQ, et al. Self-healing polymeric materials using epoxy/ mercaptan as the healant. Macromolecules 2008;41:5197 202. [25] Belbekhouche S, Ali G, Dulong V, et al. Synthesis and characterization of thermosensitive and pH-sensitive block copolymers based on polyetheramine and pullulan with different length. Carbohydr Polym 2011;86:304 12. [26] Yu J, Yang Q-X. Magnetization improvement of Fe-pillared clay with application of polyetheramine. Appl Clay Sci 2010;48:185 90. [27] Tan S, Walus S, Gustafsson T, et al. 3-D microbattery electrolyte by self-assembly of oligomers. Solid State Ionics 2011;198:26 31. [28] Guan N, Xu J, Wang L, et al. One-step synthesis of amine-functionalized thermoresponsive magnetite nanoparticles and single-crystal hollow structures. Colloids Surfaces A Physicochem Eng Asp 2009;346:221 8. [29] Kondyurin A, Komar LA, Svistkov AL. Combinatory model of curing process in epoxy composite. Compos Part B Eng 2012;43:616 20. [30] McIlroy DA, Blaiszik BJ, Caruso MM, et al. Microencapsulation of a reactive liquidphase amine for self-healing epoxy composites. Macromolecules 2010;43:1855 9. [31] Yuan YC, Rong MZ, Zhang MQ. Preparation and characterization of microencapsulated polythiol. Polymer (Guildf) 2008;49:2531 41. [32] Minami H, Kanamori H, Hata Y, et al. Preparation of microcapsules containing a curing agent for epoxy resin by polyaddition reaction with the self-assembly of phaseseparated polymer method in an aqueous dispersed system. Langmuir 2008;24:9254 9. [33] Toohey KS, Hansen CJ, Lewis JA, et al. Delivery of two-part self-healing chemistry via microvascular networks. Adv Funct Mater 2009;19:1399 405. [34] Hansen CJ, Wu W, Toohey KS, et al. Self-healing materials with ınterpenetrating microvascular networks. Adv Mater 2009;21:4143 7. [35] Wu X-F, Rahman A, Zhou Z, et al. Electrospinning core-shell nanofibers for interfacial toughening and self-healing of carbon-fiber/epoxy composites. J Appl Polym Sci 2013;129:1383 93. [36] Coope TS, Wass DF, Trask RS, et al. Metal triflates as catalytic curing agents in selfhealing fibre reinforced polymer composite materials. Macromol Mater Eng 2014;299:208 18. [37] Patrick JF, Hart KR, Krull BP, et al. Continuous self-healing life cycle in vascularized structural composites. Adv Mater 2014;26:4302 8. [38] Sinha-Ray S, Pelot DD, Zhou ZP, et al. Encapsulation of self-healing materials by coelectrospinning, emulsion electrospinning, solution blowing and intercalation. J Mater Chem 2012;22:9138. [39] Wu X-F, Yarin AL. Recent progress in interfacial toughening and damage self-healing of polymer composites based on electrospun and solution-blown nanofibers: an overview. J Appl Polym Sci 2013;130:2225 37.
Enhancements in self-curing composites
189
[40] Lee MW, An S, Jo HS, et al. Self-healing nanofiber-reinforced polymer composites. 1. tensile testing and recovery of mechanical properties. ACS Appl Mater Interfaces 2015;7:19546 54. [41] Das A, Sallat A, Bo¨hme F, et al. Ionic modification turns commercial rubber into a self-healing material. ACS Appl Mater Interfaces 2015;7:20623 30. [42] Lee MW, An S, Jo HS, et al. Self-healing nanofiber-reinforced polymer composites. 2. Delamination/debonding and adhesive and cohesive properties. ACS Appl Mater Interfaces 2015;7:19555 61. [43] Lee MW, Yoon SS, Yarin AL. Solution-blown core shell self-healing nano- and microfibers. ACS Appl Mater Interfaces 2016;8:4955 62. [44] Lee MW, An S, Lee C, et al. Self-healing transparent core-shell nanofiber coatings for anti-corrosive protection. J Mater Chem A 2014;2:7045 53. [45] An S, Liou M, Song KY, et al. Highly flexible transparent self-healing composite based on electrospun core shell nanofibers produced by coaxial electrospinning for anticorrosion and electrical insulation. Nanoscale 2015;7:17778 85. [46] Cho SH, White SR, Braun PV. Self-healing polymer coatings. Adv Mater 2009;21:645 9. [47] Lee MW, Sett S, Yoon SS, et al. Fatigue of self-healing nanofiber-based composites: static test and subcritical crack propagation. ACS Appl Mater Interfaces 2016;8:18462 70. [48] Kessler M, Sottos N, White S. Self-healing structural composite materials. Compos Part A Appl Sci Manuf 2003;34:743 53. [49] Hillewaere XKD, Du Prez FE. Fifteen chemistries for autonomous external self-healing polymers and composites. Prog Polym Sci 2015;49 50:121 53. [50] Everitt DT, Luterbacher R, Coope TS, et al. Optimisation of epoxy blends for use in extrinsic self-healing fibre-reinforced composites. Polymer (Guildf) 2015;69 283 92. [51] Pandell NW, Temin SC. Application of reactants and/or catalysts to textile fabrics in microencapsulated form; 1972. [52] Bulbenko G, Sorg E, Gallagher J. One-part polythiol compositions containing encapsulated activators; 1973. [53] Wolinski LE. Thermoplastic polyurethane resin dissolved in an acrylic monomer plus an additional acrylic monomer, free radical catalyst; 1978. [54] Garcı´a SJ, Fischer HR, van der Zwaag S. A critical appraisal of the potential of self healing polymeric coatings. Prog Org Coatings 2011;72:211 21. [55] Li GL, Zheng Z, Mo¨hwald H, et al. Silica/polymer double-walled hybrid nanotubes: synthesis and application as stimuli-responsive nanocontainers in self-healing coatings. ACS Nano 2013;7:2470 8. [56] Dry C. Procedures developed for self-repair of polymer matrix composite materials. Compos Struct 1996;35:263 9. [57] Motuku M, Vaidya UK, Janowski GM. Parametric studies on self-repairing approaches for resin infused composites subjected to low velocity impact. Smart Mater Struct 1999;8:623 38. [58] Bond IP, Trask RS, Williams HR, et al. Self healing fibre-reinforced polymer composites: an overview. Self healing materials. Dordrecht: Springer; 2007. p. 115 38. [59] Iijima S. Helical microtubules of graphitic carbon. Nature 1991;354:56 8. [60] Coleman JN, Khan U, Blau WJ, et al. Small but strong: a review of the mechanical properties of carbon nanotube polymer composites. Carbon N Y 2006;44 1624 52.
190
Self-Healing Composite Materials
[61] Wu AS, Coppola AM, Sinnott MJ, et al. Sensing of damage and healing in threedimensional braided composites with vascular channels. Compos Sci Technol 2012;72:1618 26. [62] Qian D, Wagner GJ, Liu WK, et al. Mechanics of carbon nanotubes. Appl Mech Rev 2002;55:495. [63] Troya D, Mielke SL, Schatz GC. Carbon nanotube fracture differences between quantum mechanical mechanisms and those of empirical potentials. Chem Phys Lett 2003;382:133 41. [64] Ba¸skaya G, Yıldız Y, Savk A, et al. Rapid, sensitive, and reusable detection of glucose by highly monodisperse nickel nanoparticles decorated functionalized multi-walled carbon nanotubes. Biosens Bioelectron 2017;91:728 33. [65] Sen ¸ B, Kuzu S, Demir E, et al. Highly monodisperse RuCo nanoparticles decorated on functionalized multiwalled carbon nanotube with the highest observed catalytic activity in the dehydrogenation of dimethylamine 2 borane. Int J Hydrogen Energy 2017;42:23292 8. [66] Ulus R, Yıldız Y, Eri¸s S, et al. Functionalized multi-walled carbon nanotubes (fMWCNT) as highly efficient and reusable heterogeneous catalysts for the synthesis of acridinedione derivatives. ChemistrySelect 2016;1:3861 5. [67] Yıldız Y, Esirden ˙I, Erken E, et al. Microwave (Mw)-assisted synthesis of 5-substituted 1H-Tetrazoles via [3 1 2] cycloaddition catalyzed by Mw-Pd/Co nanoparticles decorated on multi-walled carbon nanotubes. ChemistrySelect 2016;1:1695 701. [68] C ¸ elik B, Kuzu S, Erken E, et al. Nearly monodisperse carbon nanotube furnished nanocatalysts as highly efficient and reusable catalyst for dehydrocoupling of DMAB and C1 to C3 alcohol oxidation. Int J Hydrogen Energy 2016;41:3093 101. [69] Sen S, Sen F, Boghossian AA, et al. Effect of reductive dithiothreitol and trolox on nitric oxide quenching of single-walled carbon nanotubes. J Phys Chem C 2013;117:593 602. [70] Sen F, Boghossian AA, Sen S, et al. Observation of oscillatory surface reactions of riboflavin, trolox, and singlet oxygen using single carbon nanotube fluorescence spectroscopy. ACS Nano 2012;6:10632 45. [71] Zhang J, Landry MP, Barone PW, et al. Molecular recognition using corona phase complexes made of synthetic polymers adsorbed on carbon nanotubes. Nat Nanotechnol 2013;8:959 68. [72] Iverson NM, Barone PW, Shandell M, et al. In vivo biosensing via tissue-localizable near-infrared-fluorescent single-walled carbon nanotubes. Nat Nanotechnol 2013;8:873 80. [73] Ulissi ZW, Sen F, Gong X, et al. Spatiotemporal intracellular nitric oxide signaling captured using internalized, near-infrared fluorescent carbon nanotube nanosensors. Nano Lett 2014;14:4887 94. [74] Bass R. Synthesis and characterization of self-healing poly (carbonate urethane) carbon-nanotube composites, ,https://scholarcommons.usf.edu/etd/2999.; 2011 [accessed 08.01.19]. [75] Kope´c M, Szczepanowicz K, Mordarski G, et al. Self-healing epoxy coatings loaded with inhibitor-containing polyelectrolyte nanocapsules. Prog Org Coatings 2015;84:97 106. [76] Brown EN, Sottos NR, White SR. Fracture testing of a self-healing polymer composite. Exp Mech 2002;42:372 9. [77] Jones AS, Rule JD, Moore JS, et al. Catalyst morphology and dissolution kinetics of self-healing polymers. Chem Mater 2006;18:1312 17.
Enhancements in self-curing composites
191
[78] Wilson GO, Caruso MM, Reimer NT, et al. Evaluation of ruthenium catalysts for ringopening metathesis polymerization-based self-healing applications. Chem Mater 2008;20:3288 97. [79] Liu X, Sheng X, Lee JK, et al. Rheokinetic evaluation of self-healing agents polymerized by Grubbs catalyst embedded in various thermosetting systems. Compos Sci Technol 2009;69:2102 7. [80] Mauldin TC, Rule JD, Sottos NR, et al. Self-healing kinetics and the stereoisomers of dicyclopentadiene. J R Soc Interface 2007;4:389 93. [81] Rule JD, Moore JS. ROMP reactivity of endo- and exo-dicyclopentadiene. Macromolecules 2002;35:7878 82. [82] Liu X, Lee JK, Yoon SH, et al. Characterization of diene monomers as healing agents for autonomic damage repair. J Appl Polym Sci 2006;101:1266 72. [83] Zheludkevich ML, Shchukin DG, Yasakau KA, et al. Anticorrosion coatings with selfhealing effect based on nanocontainers impregnated with corrosion inhibitor. Chem Mater 2007;19:402 11. [84] Corten CC, Urban MW. Repairing polymers using oscillating magnetic field. Adv Mater 2009;21:5011 15. [85] Yang Y, Urban MW. Self-healing polymeric materials. Chem Soc Rev 2013;42:7446 67. [86] Huang L, Yi N, Wu Y, et al. Multichannel and repeatable self-healing of mechanical enhanced graphene-thermoplastic polyurethane composites. Adv Mater 2013;25:2224 8. [87] Amendola V, Dini D, Polizzi S, et al. Self-Healing of gold nanoparticles in the presence of zinc phthalocyanines and their very efficient nonlinear absorption performances. J Phys Chem C 2009;113:8688 95. [88] Skorb EV, Skirtach AG, Sviridov DV, et al. Laser-controllable coatings for corrosion protection. ACS Nano 2009;3:1753 60. [89] Skorb EV, Sviridov DV, Mo¨hwald H, et al. Light responsive protective coatings. Chem Commun 2009;0:6041 3. [90] Cortie MB, McDonagh AM. Synthesis and optical properties of hybrid and alloy plasmonic nanoparticles. Chem Rev 2011;111:3713 35. [91] Rule JD, Sottos NR, White SR. Effect of microcapsule size on the performance of selfhealing polymers. Polymer (Guildf) 2007;48:3520 9. [92] Kirkby EL, Michaud VJ, Ma˚nson JAE, et al. Performance of self-healing epoxy with microencapsulated healing agent and shape memory alloy wires. Polymer (Guildf) 2009;50:5533 8. [93] Kirkby EL, Rule JD, Michaud VJ, et al. Embedded shape-memory alloy wires for ımproved performance of self-healing polymers. Adv Funct Mater 2008;18:2253 60. [94] Luo X, Mather PT. Shape memory assisted self-healing coating. ACS Macro Lett 2013;2:152 6. [95] de Lange RG, Zijderveld JA. Shape-memory effect and the martensitic transformation of TiNi. J Appl Phys 1968;39:2195 200. [96] Sato A, Yamaji Y, Mori T. Physical properties controlling shape memory effect in FeMn-Si alloys. Acta Metall 1986;34:287 94. [97] Bar-Cohen Y. Electroactive polymers as artificial muscles: capabilities, potentials and challenges. Robotics. Reston, VA: American Society of Civil Engineers; 2000. p. 188 96. [98] Huang WM, Yang B, An L, et al. Water-driven programmable polyurethane shape memory polymer: demonstration and mechanism. Appl Phys Lett 2005;86:114105.
192
Self-Healing Composite Materials
[99] Lv H, Leng J, Liu Y, et al. Shape-memory polymer in response to solution. Adv Eng Mater 2008;10:592 5. [100] Lendlein A, Jiang H, Ju¨nger O, et al. Light-induced shape-memory polymers. Nature 2005;434:879 82. [101] Cho JW, Kim JW, Jung YC, et al. Electroactive shape-memory polyurethane composites ıncorporating carbon nanotubes. Macromol Rapid Commun 2005;26:412 16. [102] Li G, John M. A self-healing smart syntactic foam under multiple impacts. Compos Sci Technol 2008;68:3337 43. [103] Xu W, Li G. Constitutive modeling of shape memory polymer based self-healing syntactic foam. Int J Solids Struct 2010;47:1306 16. [104] Lanzara G, Yoon Y, Liu H, et al. Carbon nanotube reservoirs for self-healing materials. Nanotechnology 2009;20:335704 12. [105] Dry C. Matrix cracking repair and filling using active and passive modes for smart timed release of chemicals from fibers into cement matrices. Smart Mater Struct 1994;3:118 23. [106] Pang JWC, Bond IP. ‘Bleeding composites’—damage detection and self-repair using a biomimetic approach. Compos Part A Appl Sci Manuf 2005;36:183 8. [107] Therriault D, White SR, Lewis JA. Chaotic mixing in three-dimensional microvascular networks fabricated by direct-write assembly. Nat Mater 2003;2:265 71. [108] Norris CJ, Meadway GJ, O’Sullivan MJ, et al. Self-healing fibre reinforced composites via a bioinspired vasculature. Adv Funct Mater 2011;21:3624 33. [109] Hamilton AR, Sottos NR, White SR. Self-healing of ınternal damage in synthetic vascular materials. Adv Mater 2010;22:5159 63. [110] Williams HR, Trask RS, Bond IP. Self-healing sandwich panels: restoration of compressive strength after impact. Compos Sci Technol 2008;68:3171 7. [111] Williams HR, Trask RS, Bond IP. Self-healing composite sandwich structures. Smart Mater Struct 2007;16:1198 207. [112] Kim S, Lorente S, Bejan A. Vascularized materials: tree-shaped flow architectures matched canopy to canopy. J Appl Phys 2006;100:063525 33. [113] Esser-Kahn AP, Thakre PR, Dong H, et al. Three-dimensional microvascular fiberreinforced composites. Adv Mater 2011;23:3654 8. [114] Norris CJ, Bond IP, Trask RS. The role of embedded bioinspired vasculature on damage formation in self-healing carbon fibre reinforced composites. Compos Part A Appl Sci Manuf 2011;42:639 48. [115] Williams H, Trask R, Knights A, et al. Biomimetic reliability strategies for selfhealing vascular networks in engineering materials. J R Soc Interface 2008;5:735 47. [116] Koralagundi Matt AK, Strong S, ElGammal T, et al. Development of novel selfhealing polymer composites for use in wind turbine blades. J Energy Resour Technol 2015;137:051202 7. [117] Scheiner M, Dickens TJ, Okoli O. Progress towards self-healing polymers for composite structural applications. Polymer (Guildf) 2016;83:260 82.