Preparation and application of microcapsules containing toluene-di-isocyanate for self-healing of concrete

Du, Wei; Yu, Jianying; Gu, Yi; Liu, Ying; Han, Xiaobin; Liu, Quantao

doi:10.1016/j.conbuildmat.2019.01.007

Cited by 85 publications

(33 citation statements)

References 26 publications

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“…One-part adhesives harden via radiation, heat, or moisture. Because of that, adhesives that harden when exposed to light (77), high temperature (22), or moisture (cyanoacrylates (78,79) or polyurethanes (80,81)) have been proposed as healing agents. Once a crack appears in concrete, the interior of the matrix and the adhesive will be exposed to ambient conditions, activating the healing reaction.…”

Section: Reactive Adhesivesmentioning

confidence: 99%

“…Some self-healing agents do not work effectively under certain environments, such as SAPs in marine environments (55,61) or CA in environments without direct contact with water (17). Systems based on reactive adhesives can activate with different systems, moisture (78,79), light (77), high temperature (22), or with their activator component (24,83). For those self-healing systems that are activated with water, the presence of water can become at the same time a mechanism that transports aggressive agents that start some degradation phenomena as well as the activator for self-healing reactions, in a kind of love-hate relationship (138).…”

Section: B) For Cracks At What Construction Stage?mentioning

confidence: 99%

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Self-healing concrete-What Is it Good For?

2021

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Self-healing of concrete is the process in which the material regenerates itself repairing inner cracks. This process can be produced by autogenous or autonomous healing. Autogenous healing is a natural process, produced by carbonation and/or continuing hydration. Autonomous healing is based on the use of specific agents to produce self-healing, which can be added directly to the concrete matrix, embedded in capsules or introduced through vascular networks. Some examples are superabsorbent polymers, crystalline admixtures, microencapsulated sodium silicate, and bacteria. This review is structured into two parts. The first part is an overview of self-healing concrete that summarises the basic concepts and the main advances produced in the last years. The second part is a critical discussion on the feasibility of self-healing concrete, its possibilities, current weaknesses, and challenges that need to be addressed in the coming years.

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Section: Reactive Adhesivesmentioning

confidence: 99%

Section: B) For Cracks At What Construction Stage?mentioning

confidence: 99%

Self-healing concrete-What Is it Good For?

2021

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“…It was concluded that the upper strength recovery ratio was possible by increasing the concentration of the repair material. Meanwhile, Yu et al [ 74 ] prepared single-component microcapsules with toluene-di-isocyanate (TDI) and paraffin serving as the repair agent and shell, respectively. The findings revealed that encapsulation of TDI within the paraffin shell was successful and a better self-repair capability was demonstrated by mortars containing the microcapsules.…”

Section: Mechanism Of Self-healing In Cementitious Materialsmentioning

confidence: 99%

Biomimetic Self-Healing Cementitious Construction Materials for Smart Buildings

Shah

Huseien

2020

Biomimetics

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Climate change is anticipated to have a major impact on concrete structures through increasing rates of deterioration as well the impacts of extreme weather events. The deterioration can affect directly or indirectly climate change in addition to the variation in the carbon dioxide concentration, temperature and relative humidity. The deterioration that occurs from the very beginning of the service not only reduces the lifespan of the concretes but also demands more cement to maintain the durability. Meanwhile, the repair process of damaged parts is highly labor intensive and expensive. Thus, the self-healing of such damages is essential for the environmental safety and energy cost saving. The design and production of the self-healing as well as sustainable concretes are intensely researched within the construction industries. Based on these factors, this article provides the materials and methods required for a comprehensive assessment of self-healing concretes. Past developments, recent trends, environmental impacts, sustainability, merits and demerits of several methods for the production of self-healing concrete are discussed and analyzed.

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“…When the metal substrate is corroded because of coating rupture, the repair agent in the coating can move to the damaged position in time, and react with catalyst to form a new barrier layer, so that the damaged anti‐corrosion coating can repair itself and prevent metal corrosion. [ 7–10 ] Repair agents, such as dicyclopentadiene, [ 11,12 ] reactive epoxy resin, [ 13,14 ] linseed oil, [ 15 ] and isocyanate [ 16,17 ] ) have been microencapsulated and applied in self‐healing anti‐corrosive coatings. For dicyclopentadiene, reactive epoxy resin and many other repair agents, catalyst that initiates the polymerization of repair agents needs to be added to the coating.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Tung Oil‐Loaded PU/PANI Microcapsules and Synergetic Anti‐Corrosion Properties of Self‐Healing Epoxy Coatings

Feng

Cui

Zhang

et al. 2020

Macro Materials & Eng

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Tung oil is used as a catalyst‐free repair agent. Tung oil‐loaded polyurethane (PU) microcapsules are prepared by interfacial polymerization in a SiO2‐stabilized Pickering emulsion system, polyaniline (PANI) is deposited in situ on the PU microcapsule surface, and tung oil‐loaded PU/PANI double‐layer shell microcapsules are obtained. Synthesized PU/PANI microcapsules showed the characteristic dark‐green color of conductive PANI. The average particle size is 31.1 ± 8.1 µm and the core content is 45.1 ± 4.3 wt%. The microcapsules have a good thermal stability, and the chemical structure of the PU/PANI wall and tung oil core is confirmed by Fourier transform infrared analysis. Self‐healing anti‐corrosion coatings are prepared by adding 10 wt% microcapsules into epoxy resin. The corrosion resistance properties of the self‐healing coating are evaluated by immersing scratched coatings in 10 wt% NaCl solution for 15 days. The self‐healing coating with 10 wt% tung oil‐loaded PU/PANI microcapsules have the best anti‐corrosion property, and slight corrosion do not occur until 15 days after immersion in salt solution. The self‐healing and anti‐corrosion mechanism are revealed. The tung oil core and the PANI wall of microcapsules contributed synergistically to the excellent self‐healing and anti‐corrosion properties of the coating through the formation of self‐healing films and passivation layers.

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Preparation and application of microcapsules containing toluene-di-isocyanate for self-healing of concrete

Cited by 85 publications

References 26 publications

Self-healing concrete-What Is it Good For?

Self-healing concrete-What Is it Good For?

Biomimetic Self-Healing Cementitious Construction Materials for Smart Buildings

Preparation of Tung Oil‐Loaded PU/PANI Microcapsules and Synergetic Anti‐Corrosion Properties of Self‐Healing Epoxy Coatings

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