Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

Search Results (32)

Search Parameters:
Keywords = initial self-healing temperature

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
31 pages, 8222 KiB  
Article
Multifunctional 3D-Printable Photocurable Elastomer with Self-Healing Capability Derived from Waste Cooking Oil
by Pengyu Wang, Jiahui Sun, Mengyu Liu, Chuanyang Tang, Yang Yang, Guanzhi Ding, Qing Liu and Shuoping Chen
Molecules 2025, 30(8), 1824; https://doi.org/10.3390/molecules30081824 - 18 Apr 2025
Viewed by 515
Abstract
This study presents a sustainable approach to transform waste cooking oil (WCO) into a multifunctional 3D-printable photocurable elastomer with integrated self-healing capabilities. A linear monomer, WCO-based methacrylate fatty acid ethyl ester (WMFAEE), was synthesized via a sequential strategy of transesterification, epoxidation, and ring-opening [...] Read more.
This study presents a sustainable approach to transform waste cooking oil (WCO) into a multifunctional 3D-printable photocurable elastomer with integrated self-healing capabilities. A linear monomer, WCO-based methacrylate fatty acid ethyl ester (WMFAEE), was synthesized via a sequential strategy of transesterification, epoxidation, and ring-opening esterification. By copolymerizing WMFAEE with hydroxypropyl acrylate (HPA), a novel photocurable elastomer was developed, which could be amenable to molding using an LCD light-curing 3D printer. The resulting WMFAEE-HPA elastomer exhibits exceptional mechanical flexibility (elongation at break: 645.09%) and autonomous room-temperature self-healing properties, achieving 57.82% recovery of elongation after 24 h at 25 °C. Furthermore, the material demonstrates weldability (19.97% retained elongation after 12 h at 80 °C) and physical reprocessability (7.75% elongation retention after initial reprocessing). Additional functionalities include pressure-sensitive adhesion (interfacial toughness: 70.06 J/m2 on glass), thermally triggered shape memory behavior (fixed at −25 °C with reversible deformation/recovery at ambient conditions), and notable biodegradability (13.25% mass loss after 45-day soil burial). Molecular simulations reveal that the unique structure of the WMFAEE monomer enables a dual mechanism of autonomous self-healing at room temperature without external stimuli: chain diffusion and entanglement-driven gap closure, followed by hydrogen bond-mediated network reorganization. Furthermore, the synergy between monomer chain diffusion/entanglement and dynamic hydrogen bond reorganization allows the WMFAEE-HPA system to achieve a balance of multifunctional integration. Moreover, the integration of these multifunctional attributes highlights the potential of this WCO-derived photocurable elastomer for various possible 3D printing applications, such as flexible electronics, adaptive robotics, environmentally benign adhesives, and so on. It also establishes a paradigm for converting low-cost biowastes into high-performance smart materials through precision molecular engineering. Full article
Show Figures

Graphical abstract

16 pages, 4593 KiB  
Article
Self-Healing Properties of Crosslinked PMMA-DVB Copolymer Microcapsules Based on Interfacial Polymerization
by Xiaowei Jiang, Chengwu Tang, Jiachuan Yu, Yuankai Zhou and Xue Zuo
Polymers 2025, 17(5), 569; https://doi.org/10.3390/polym17050569 - 21 Feb 2025
Viewed by 714
Abstract
To address the issue of metal corrosion caused by microcracks in the coating on the steel structures of offshore drilling platforms, this study employs interfacial polymerization to prepare microcapsules with self-healing functionality for coatings. The microcapsules are fabricated through free radical polymerization between [...] Read more.
To address the issue of metal corrosion caused by microcracks in the coating on the steel structures of offshore drilling platforms, this study employs interfacial polymerization to prepare microcapsules with self-healing functionality for coatings. The microcapsules are fabricated through free radical polymerization between methyl methacrylate (MMA) and ammonium persulfate (APS), along with crosslinking reactions involving divinylbenzene (DVB). The particle size distribution and surface morphology of the microcapsules were optimized by adjusting process parameters using optical microscopy and scanning electron microscopy. Fourier-transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) were used to characterize the chemical structure and thermal stability of the microcapsules. The results show that when polyvinyl alcohol is used as the emulsifier, the oil–water ratio was 7.5:200, the amount of emulsifier was 1 wt%, the emulsification speed was 2500 r/min, the amount of initiator was 2 g, the core-to-wall ratio was 4:1, and the ambient temperature was 60 °C showed good sphericity, the microcapsules prepared under the optimized parameters exhibit good sphericity, a smooth surface, and an average particle size of 35.17 μm. They have a good core material encapsulation effect and thermal stability, which impart excellent self-healing properties to the epoxy coating. Such microcapsules have promising applications in mitigating the problem of metal corrosion of coatings due to microcracks and improving the service life and reliability of equipment. Full article
(This article belongs to the Section Polymer Networks and Gels)
Show Figures

Figure 1

23 pages, 5013 KiB  
Article
Study on the Impact of Diluent Dosages on the Epoxy–Polythiol Self-Healing System
by Jiajia Sheng, Yang Guo, Xin Pang, Wenjing Ma, Hailu Yang, Yalin Liu, Linbing Wang and Shanglin Song
Polymers 2025, 17(4), 538; https://doi.org/10.3390/polym17040538 - 19 Feb 2025
Viewed by 633
Abstract
Self-healing technology is an effective method for enhancing the crack resistance of cement-based composites. This study focuses on the impact of the environmentally friendly diluent C12-14 alkyl glycidyl ether (AGE) on the performance of the epoxy resin–polythiol (rimethylolpropane tris (3-mercaptopropionate), TMPMP) self-healing system, [...] Read more.
Self-healing technology is an effective method for enhancing the crack resistance of cement-based composites. This study focuses on the impact of the environmentally friendly diluent C12-14 alkyl glycidyl ether (AGE) on the performance of the epoxy resin–polythiol (rimethylolpropane tris (3-mercaptopropionate), TMPMP) self-healing system, examining core fluidity, microcapsule properties, molecular dynamics, and the mechanical properties of cured products. The results show that as the AGE dosage increases, the particle size distribution of microcapsules becomes more concentrated, and the dispersion of particles is improved. Fourier-transform infrared spectroscopy confirms the successful encapsulation of E-51 and AGE. Microcapsules maintain structural integrity at high temperatures of 423.15 K. The onset thermal degradation temperature of the mixture shows an increasing trend with reduced AGE dosage. Specifically, TMPMP35% exhibits an onset degradation temperature of 370.95 K, while that of TMPMP20% is increased by 57.57% compared to TMPMP35%. Conversely, the initial and peak temperatures of the curing reaction decrease with less AGE incorporation. Thermodynamic analysis reveals that activation energy (E) initially increases and then decreases with increasing AGE. The frequency factor (A) correlates positively with the heating rate, indicating that the curing reaction’s reactivity is closely linked to heating rate. Minor variations in the reaction rate constant (k) indicate that the self-healing system maintains stable reactive activity at low temperatures. Notably, the AGE dosage significantly affects the rigidity of the self-healing system; the average Young’s modulus inversely correlates with AGE dosage, with the most substantial decrease of 5.88% occurring when AGE increases from 30% to 35%. This study offers insights into optimizing diluent ratios to balance self-healing and mechanical properties, essential for developing high-performance self-healing cement materials. Full article
(This article belongs to the Section Smart and Functional Polymers)
Show Figures

Figure 1

21 pages, 8190 KiB  
Article
Effect of Melamine Formaldehyde Resin Encapsulated UV Acrylic Resin Primer Microcapsules on the Properties of UV Primer Coating
by Yuming Zou, Yongxin Xia and Xiaoxing Yan
Polymers 2024, 16(16), 2308; https://doi.org/10.3390/polym16162308 - 15 Aug 2024
Cited by 9 | Viewed by 1546
Abstract
Ultra-Violet (UV) coatings are widely adaptable of substrates and produce low emissions of volatile organic compounds. UV coatings can extend service life by adding self-healing microcapsules that restore integrity after sustaining damage. In this study, UV coating was used as a core material; [...] Read more.
Ultra-Violet (UV) coatings are widely adaptable of substrates and produce low emissions of volatile organic compounds. UV coatings can extend service life by adding self-healing microcapsules that restore integrity after sustaining damage. In this study, UV coating was used as a core material; microcapsules were produced and added to the UV coating to enhance its self-healing property, providing a good protection for both the UV coating and the substrate. UV primer microcapsules were prepared with UV primer as the core material and melamine formaldehyde resin as the wall material. The UV primer containing more than 98.0% solids content was mainly composed of epoxy acrylic resin, polyester acrylic resin, trihydroxy methacrylate, trimethyl methacrylate, and photo initiator. The preparation process of the UV primer microcapsules was optimized. Further, the UV coating was prepared with better UV primer microcapsules, and the effects of the UV primer microcapsules alongside the comprehensive properties of the coating were studied. The best preparation process for the UV primer microcapsules was as follows: the wall-core mass ratio was 1:0.50, Triton X-100 and Span-20 as emulsifiers with an HLB value of 10.04, the microcapsule reaction temperature was 70 °C, and the reaction time of the was 3.0 h. When the quantity of the UV primer microcapsules increased in the coating, color difference ΔE of the coating increased, gloss decreased, transmittance decreased, elongation at break increased and then decreased, roughness increased, and self-healing rate first increased and then decreased. When the addition of the UV primer microcapsules reached 2.0%, the color difference ΔE of the coating was 1.71, the gloss was 106.63 GU, the transmittance was 78.80%, the elongation at break was 3.62%, the roughness was 0.204 μm, and the self-healing rate was 28.56%, which were the best comprehensive properties of the UV primer. To improve the comprehensive properties of the UV coatings, the UV coatings were modified by a microcapsule technology, which gave the UV coatings a better self-healing property. The application range of microcapsules for the UV coatings was broadened. Based on the previous research of microcapsules in UV coatings, the results further refined the study of the effects of adding self-healing microcapsules to UV coatings using the UV coating itself as the core material. Full article
(This article belongs to the Special Issue Recent Advances in Polymer Composites for Functional Applications)
Show Figures

Figure 1

16 pages, 4325 KiB  
Article
Processing and Mechanics of Aromatic Vitrimeric Composites at Elevated Temperatures and Healing Performance
by Tanaya Mandal, Unal Ozten, Louis Vaught, Jacob L. Meyer, Ahmad Amiri, Andreas Polycarpou and Mohammad Naraghi
J. Compos. Sci. 2024, 8(7), 252; https://doi.org/10.3390/jcs8070252 - 1 Jul 2024
Cited by 6 | Viewed by 1752
Abstract
Carbon fiber reinforced polymer (CFRP) composites are renowned for their exceptional mechanical properties, with applications in industries such as automotive, aerospace, medical, civil, and beyond. Despite these merits, a significant challenge in CFRPs lies in their repairability and maintenance. This study, for the [...] Read more.
Carbon fiber reinforced polymer (CFRP) composites are renowned for their exceptional mechanical properties, with applications in industries such as automotive, aerospace, medical, civil, and beyond. Despite these merits, a significant challenge in CFRPs lies in their repairability and maintenance. This study, for the first time, delves into the processing and self-healing capability of aromatic thermosetting co-polyester vitrimer-based carbon fiber composites through mechanical testing. Vitrimers are an emerging class of thermosetting polymers, which, owing to their exchangeable covalent bonds, enable the re-formation of bonds across cracks. The specific vitrimer chosen for this study is an aromatic thermosetting co-polyester (ATSP). The mechanical properties of samples were analyzed initially through three-point bending (3PB) testing at room temperature before and after healing (by curing samples for 2 h at 280 °C). Samples were also 3PB tested at 100 °C to analyze their mechanical properties at an elevated temperature for comparison to the samples tested at room temperature. To investigate the fracture properties, optical microscopy images of samples were taken after 3PB tests, which were analyzed to observe crack initiation and crack growth behavior. Through load–displacement curves from double cantilever beam (DCB) mechanical testing, the Mode I crack initiation fracture toughness values of self-healed composites and control composites were calculated to evaluate healing efficiency in ATSP CFRP composites cured at 280 °C for 2 h. Scanning electron microscopy (SEM) showed a similar surface morphology of cracks before and after self-healing. Micro-computed tomography (CT) X-ray imaging confirmed that the healed samples closely resembled the as-fabricated ones, with the exception of some manufacturing voids, caused by outgassing in the initial healing cycle. This research demonstrated the ability for the in situ repair of ATSP CFRPs by restoring the fracture toughness to values comparable to the pristine composite (~289 J/m2). Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume III)
Show Figures

Graphical abstract

13 pages, 4026 KiB  
Article
Constructing Self-Healing Polydimethylsiloxane through Molecular Structure Design and Metal Ion Bonding
by Lvchao Qiu, Yutong Zhou, Zhoufeng Zhao, Qi Wang, Lijun Chu and Shipeng Wen
Polymers 2024, 16(10), 1309; https://doi.org/10.3390/polym16101309 - 7 May 2024
Cited by 2 | Viewed by 1839
Abstract
Self-healing polydimethylsiloxane (PDMS) has garnered significant attention due to its potential applications across various fields. In this study, a functionalized modification of PDMS containing di-aminos was initially conducted using 2,6-pyridinedicarbonyl chloride to synthesize pyridine-PDMS (Py-PDMS). Subsequently, rare earth metal europium ions (Eu3+ [...] Read more.
Self-healing polydimethylsiloxane (PDMS) has garnered significant attention due to its potential applications across various fields. In this study, a functionalized modification of PDMS containing di-aminos was initially conducted using 2,6-pyridinedicarbonyl chloride to synthesize pyridine-PDMS (Py-PDMS). Subsequently, rare earth metal europium ions (Eu3+) were incorporated into Py-PDMS. Due to the coordination interaction between Eu3+ and organic ligands, a coordination cross-linking network was created within the Py-PDMS matrix, resulting in the fabrication of Eu3+-Py-PDMS elastomer. At a molar ratio of Eu3+ to ligands of 1:1, the tensile strength of Eu3+-Py-PDMS reached 1.4 MPa, with a fracture elongation of 824%. Due to the dynamic reversibility of coordination bonds, Eu3+-Py-PDMS with a metal-to-ligand molar ratio of 1:2 exhibited varying self-healing efficiencies at different temperatures. Notably, after 4 h of repair at 60 °C, its self-healing efficiency reached nearly 100%. Furthermore, the gas barrier properties of Eu3+-Py-PDMS with a molar ratio of 1:1 was improved compared with that of Eu3+-Py-PDMS with a molar ratio of 1:1. This study provides an effective strategy for the design and fabrication of PDMS with high mechanical strength, high gas barrier properties, and exceptional self-healing efficiency. Full article
Show Figures

Figure 1

26 pages, 4954 KiB  
Review
Recent Advances of Self-Healing Materials for Civil Engineering: Models and Simulations
by Cen-Ying Liao, Lin Zhang, Si-Yu Hu, Shuai-Jie Xia and D. M. Li
Buildings 2024, 14(4), 961; https://doi.org/10.3390/buildings14040961 - 1 Apr 2024
Cited by 12 | Viewed by 8664
Abstract
Empowering materials with self-healing capabilities is an attractive approach for sustainable development. This strategy involves using different methods to automatically heal microcracks and damages that occur during the service life of materials or structures. Initially, this study begins with an in-depth exploration of [...] Read more.
Empowering materials with self-healing capabilities is an attractive approach for sustainable development. This strategy involves using different methods to automatically heal microcracks and damages that occur during the service life of materials or structures. Initially, this study begins with an in-depth exploration of self-healing characteristics found in materials such as concrete, asphalt, and polymers. The differences and comparative merits and demerits between autogenous (intrinsic) healing and autonomic (extrinsic) healing are discussed, and it is found that intrinsic healing is more promising. Subsequently, the study explores how models are applied to assess self-healing efficiency. The results indicate that time and temperature have significant impacts on the self-healing process. However, there is a scarcity of research exploring the effects of load factors during service life. Computational simulation methodologies for microcapsules and asphalt within self-healing materials are investigated. Multiscale characterization and machine learning can further elucidate the healing mechanisms and facilitate the establishment of computational models. This study endeavors to realize the maximum capabilities of self-healing materials, paving the way for the design of sustainable and more effective self-repairing materials for various applications. Full article
Show Figures

Figure 1

30 pages, 3770 KiB  
Review
Recent Advances in Polymer Nanocomposites: Unveiling the Frontier of Shape Memory and Self-Healing Properties—A Comprehensive Review
by Huma Jamil, Muhammad Faizan, Muhammad Adeel, Teofil Jesionowski, Grzegorz Boczkaj and Aldona Balčiūnaitė
Molecules 2024, 29(6), 1267; https://doi.org/10.3390/molecules29061267 - 13 Mar 2024
Cited by 34 | Viewed by 8601
Abstract
Shape memory and self-healing polymer nanocomposites have attracted considerable attention due to their modifiable properties and promising applications. The incorporation of nanomaterials (polypyrrole, carboxyl methyl cellulose, carbon nanotubes, titania nanotubes, graphene, graphene oxide, mesoporous silica) into these polymers has significantly enhanced their performance, [...] Read more.
Shape memory and self-healing polymer nanocomposites have attracted considerable attention due to their modifiable properties and promising applications. The incorporation of nanomaterials (polypyrrole, carboxyl methyl cellulose, carbon nanotubes, titania nanotubes, graphene, graphene oxide, mesoporous silica) into these polymers has significantly enhanced their performance, opening up new avenues for diverse applications. The self-healing capability in polymer nanocomposites depends on several factors, including heat, quadruple hydrogen bonding, π–π stacking, Diels–Alder reactions, and metal–ligand coordination, which collectively govern the interactions within the composite materials. Among possible interactions, only quadruple hydrogen bonding between composite constituents has been shown to be effective in facilitating self-healing at approximately room temperature. Conversely, thermo-responsive self-healing and shape memory polymer nanocomposites require elevated temperatures to initiate the healing and recovery processes. Thermo-responsive (TRSMPs), light-actuated, magnetically actuated, and Electrically actuated Shape Memory Polymer Nanocomposite are discussed. This paper provides a comprehensive overview of the different types of interactions involved in SMP and SHP nanocomposites and examines their behavior at both room temperature and elevated temperature conditions, along with their biomedical applications. Among many applications of SMPs, special attention has been given to biomedical (drug delivery, orthodontics, tissue engineering, orthopedics, endovascular surgery), aerospace (hinges, space deployable structures, morphing aircrafts), textile (breathable fabrics, reinforced fabrics, self-healing electromagnetic interference shielding fabrics), sensor, electrical (triboelectric nanogenerators, information energy storage devices), electronic, paint and self-healing coating, and construction material (polymer cement composites) applications. Full article
Show Figures

Graphical abstract

19 pages, 9769 KiB  
Article
Corrosion Behavior of 10 ppi TAD3D/5A05Al Composite in a Chloride Environment
by Zishen Li, Shengpu Wang, Yuxin Chen, Gaofeng Fu and Lan Jiang
Materials 2024, 17(6), 1280; https://doi.org/10.3390/ma17061280 - 10 Mar 2024
Cited by 1 | Viewed by 1450
Abstract
This study utilizes desalted and denitrated treated aluminum dross (TAD) as a raw material, along with kaolin and 10 ppi (pores per inch) polyurethane foam as a template. The slurry is converted into an aluminum dross green body with a three-dimensional network structure [...] Read more.
This study utilizes desalted and denitrated treated aluminum dross (TAD) as a raw material, along with kaolin and 10 ppi (pores per inch) polyurethane foam as a template. The slurry is converted into an aluminum dross green body with a three-dimensional network structure using the impregnation method. A three-dimensional network aluminum dross ceramic framework (TAD3D) is created at a sintering temperature of 1350 °C. The liquid 5A05 aluminum alloy at a temperature of 950 °C infiltrates into the voids of TAD3D through pressureless infiltration, resulting in TAD3D/5A05Al composite material with an interpenetrating phase composite (IPC) structure. The corrosion behavior of TAD3D/5A05 composite material in sodium chloride solution was examined using the salt spray test (NSS) method. The study shows that the pores of the TAD3D framework, produced by sintering aluminum dross as raw material, are approximately 10 ppi. The bonding between TAD3D and 5A05Al interfaces is dense, with strong interfacial adhesion. The NSS corrosion time ranged from 24 h to 360 h, during which the composite material underwent pitting corrosion, crevice corrosion and self-healing processes. Results from Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) indicate that, as corrosion progresses, the Ecorr of TAD3D/5A05Al decreases from −0.718 V to −0.786 V, and Icorr decreases from 0.398 μA·cm−2 to 0.141 μA·cm−2. A dense oxide film forms on the surface of the composite material, increasing the anodic Tafel slope and decreasing the cathodic Tafel slope, thus slowing down the rates of cathodic and anodic reactions. Factors such as lower interface corrosion resistance or a relatively weak passivation film at the interface do not significantly diminish the corrosion resistance of TAD3D and 5A05Al. The corrosion resistance of the composite material initially decreases and then increases. Full article
(This article belongs to the Special Issue Recycling and Sustainability of Industrial Solid Waste)
Show Figures

Figure 1

19 pages, 10628 KiB  
Article
Self-Healing of Pluronic® F127 Hydrogels in the Presence of Various Polysaccharides
by Alexandra Lupu, Luiza Madalina Gradinaru, Daniela Rusu and Maria Bercea
Gels 2023, 9(9), 719; https://doi.org/10.3390/gels9090719 - 5 Sep 2023
Cited by 24 | Viewed by 6566
Abstract
Thermoresponsive Pluronic® F127 (PL) gels in water were investigated through rheological tests in different shear conditions. The gel strength was tuned with the addition of 1% polysaccharide solution. In the presence of xanthan gum (XG), the viscoelastic behavior of PL-based hydrogels was improved [...] Read more.
Thermoresponsive Pluronic® F127 (PL) gels in water were investigated through rheological tests in different shear conditions. The gel strength was tuned with the addition of 1% polysaccharide solution. In the presence of xanthan gum (XG), the viscoelastic behavior of PL-based hydrogels was improved in aqueous environment, but the rheological behavior was less changed with the addition of XG in PBS solutions, whereas in the presence of 0.1 M NaCl, the viscoelastic parameters decreased. PL micellar networks exhibited a self-healing ability, recovering their initial structure after applying cycles of high strain. The rheological characteristics of the PL hydrogel changed with the addition of 1% polysaccharides (xanthan gum, alginate, κ-carrageenan, gellan, or chitosan). PL/polysaccharide systems form temperature-responsive hydrogels with shear thinning behavior, yield stress, and self-healing ability, being considered a versatile platform for injectable biomaterials or bioinks. Thus, in the presence of xanthan gum in aqueous medium, the gel strength was improved after applying a high strain (the values of elastic modulus increased). The other investigated natural polymers induced specific self-healing behaviors. Good performances were observed with the addition of gellan gum, alginate, and κ-carrageenan, but for high values of strain, the ability to recover the initial structure decreased. A modest self-healing behavior was observed in the presence of chitosan and xanthan gum dissolved in NaCl solution. Full article
(This article belongs to the Special Issue Hydrogel-Based Novel Biomaterials: Achievements and Prospects)
Show Figures

Figure 1

20 pages, 3292 KiB  
Article
Multiscale Mathematical Analysis of Influencing Factors and Experimental Verification of Microcrack Self-Healing Efficiency of Bitumen Composites Using Microcapsules
by Xin-Yu Wang, Qian Sun, Sai Wang, Rong-Yue Shao and Jun-Feng Su
Materials 2023, 16(14), 5073; https://doi.org/10.3390/ma16145073 - 18 Jul 2023
Cited by 2 | Viewed by 1305
Abstract
The preparation and application of microcapsules containing healing agents have become a crucial way to enhance the self-healing capability of bitumen. This intelligent material has become a hot topic in the field of pavement material and has greatly stimulated the development and applications [...] Read more.
The preparation and application of microcapsules containing healing agents have become a crucial way to enhance the self-healing capability of bitumen. This intelligent material has become a hot topic in the field of pavement material and has greatly stimulated the development and applications of pavement engineering. However, there has been no research focused on the relationship of the multistructures from the viewpoint of molecular-size, microsize, and macrosize, which significantly limits the predictions of the self-healing efficiency and structure design of this self-healing material. The purpose of this study was to make a mathematical analysis of the influencing factors of self-healing efficiency based on the self-healing mechanism of bitumen using microcapsules, fully considering the structural dimensions, preparation conditions, and self-healing conditions. In the mathematical analysis, the cross-linking degree of the shell material molecules of the microcapsules was considered for its damage strength from the perspective of molecular structure. The final tip stress of the microcrack was believed to be equal to the puncture strength of the microcapsules in terms of microsize. From a macroscale point of view, the amount of healing agent released from the microcapsule rupture was considered more significant than or equal to the volume of the microcracks. At the same time, the time–temperature superposition principle was applied to simplify the influence factors. The above derivation based on multiscale structures found that the additive amount of the microcapsules, temperature, and time were the three main influencing factors on the self-healing features of bitumen. Finally, the experimental data was investigated considering the three factors, which thoroughly verified the feasibility of the derivation. All results will help to establish a bridge between the initial structural design of self-healing bitumen and the prediction of the final self-healing effects. Full article
(This article belongs to the Special Issue Polymer Composites: Design, Manufacturing and Recycling)
Show Figures

Figure 1

20 pages, 7582 KiB  
Article
Influence of Electromagnetic Inductive Microcapsules on Self-Healing Ability of Limestone Calcined Clay Cement (LC3) Mortar
by Wei Du, Bo Liu, Zhengang Feng, Quantao Liu, Mingli Wu and Danying Zuo
Polymers 2023, 15(14), 3081; https://doi.org/10.3390/polym15143081 - 18 Jul 2023
Cited by 6 | Viewed by 1841
Abstract
In order to promote the sustainability of cementitious materials, it is imperative to reduce the level of environmental pollution and energy consumption during their production, as well as extend the service life of building elements. This study utilized limestone, calcined clay and gypsum [...] Read more.
In order to promote the sustainability of cementitious materials, it is imperative to reduce the level of environmental pollution and energy consumption during their production, as well as extend the service life of building elements. This study utilized limestone, calcined clay and gypsum as supplementary cementitious materials to prepare LC3 mortar, replacing 50% of ordinary silicate cement. Three types of microcapsules (M1, M2 and M3) were prepared using IPDI as a healing agent and polyethylene wax, polyethylene wax/nano-CaCO3 or polyethylene wax/ferrous powder as shell materials. The microcapsules were added to the LC3 mortar and tested for their effects on the mechanical properties, pore structure and permeability of mortars. Pre-loaded and pre-cracked mortar specimens were subjected to room temperature or under an applied magnetic field to evaluate the self-healing ability of the microcapsules on mortars. The kinetics of the curing reaction between IPDI and moisture were investigated using quasi-first-order and quasi-second-order reaction kinetic models. The experimental results showed that the mortar (S3) mixed with electromagnetic inductive microcapsules (M3) exhibited the best self-healing ability. The compressive strength retention, the percentage of pores larger than 0.1 μm, recovery of chloride diffusion coefficient and maximum amplitude after self-healing of S3 were 92.2%, 42.6%, 78.9% and 28.87 mV, respectively. Surface cracks with an initial width of 0.3~0.5 mm were healed within 24 h. The curing reaction between IPDI and moisture during self-healing followed a quasi-second-order reaction kinetic model. Full article
(This article belongs to the Section Polymer Composites and Nanocomposites)
Show Figures

Figure 1

18 pages, 11808 KiB  
Article
Electrically and Thermally Triggered Three-Dimensional Graphene-Foam-Reinforced Shape Memory Epoxy Composites
by Adeyinka Idowu, Tony Thomas, Jenniffer Bustillos, Benjamin Boesl and Arvind Agarwal
Polymers 2023, 15(13), 2903; https://doi.org/10.3390/polym15132903 - 30 Jun 2023
Cited by 5 | Viewed by 2122
Abstract
Shape memory polymer (SMP) epoxy composites have attracted significant attention due to their easy processing, lightweight nature, and ability to recover strain. However, their limited recovery rate and inferior mechanical properties have hindered their functional applications. This research explores the potential of three-dimensional [...] Read more.
Shape memory polymer (SMP) epoxy composites have attracted significant attention due to their easy processing, lightweight nature, and ability to recover strain. However, their limited recovery rate and inferior mechanical properties have hindered their functional applications. This research explores the potential of three-dimensional (3D) graphene foam (GrF) as a highly efficient reinforcement for SMP epoxy composites. We demonstrated that the incorporation of a mere 0.13 wt.% GrF into mold-cast SMP epoxy leads to a 19% increase in the glass transition temperature (Tg). To elucidate the reinforcing mechanism, we fabricated and extensively analyzed composites with varying weight percentages of GrF. The GrF-based SMP epoxy composite exhibits a 57% increase in thermal conductivity, measuring 0.296 W mK−1 at 70 °C, due to the interconnected 3D graphene network within the matrix. Notably, this composite also demonstrates remarkable electrical conductivity, making it suitable for dual-triggering applications. The GrF-SMP epoxy composite achieves a maximum shape recovery ratio and a significant 23% improvement in the recovery rate, effectively addressing the issue of slow recovery associated with SMPs. We investigated the effect of switching temperatures on the shape recovery rate. We identified the optimal triggering temperature to initiate shape recovery for epoxy SMP and GrF-epoxy SMP as thermal energy equivalent to Tg + 20 °C. Additionally, we fabricated a bird-shaped composite using GrF reinforcement, which showcases self-healing capabilities through the crack opening and closure and serves as a tangible demonstration of the transformative potential of the composite. These GrF-epoxy SMP composites, responsive to stimuli, hold immense promise for diverse applications, such as mechanical systems, wearable sensors, morphing wings, foldable robots, and antennas. Full article
Show Figures

Figure 1

19 pages, 32127 KiB  
Article
New Self-Healing Metallosupramolecular Copolymers with a Complex of Cobalt Acrylate and 4′-Phenyl-2,2′:6′,2″-terpyridine
by Evgeny S. Sorin, Rose K. Baimuratova, Igor E. Uflyand, Evgeniya O. Perepelitsina, Denis V. Anokhin, Dmitry A. Ivanov and Gulzhian I. Dzhardimalieva
Polymers 2023, 15(6), 1472; https://doi.org/10.3390/polym15061472 - 16 Mar 2023
Cited by 6 | Viewed by 2698
Abstract
Currently, the chemistry of self-healing polymers is aimed not only at obtaining materials with high self-healing efficiency, but also at improving their mechanical performance. This paper reports on a successful attempt to obtain self-healing copolymers films of acrylic acid, acrylamide and a new [...] Read more.
Currently, the chemistry of self-healing polymers is aimed not only at obtaining materials with high self-healing efficiency, but also at improving their mechanical performance. This paper reports on a successful attempt to obtain self-healing copolymers films of acrylic acid, acrylamide and a new metal-containing complex of cobalt acrylate with a 4′-phenyl-2,2′:6′,2″-terpyridine ligand. Samples of the formed copolymer films were characterized by ATR/FT-IR and UV-vis spectroscopy, elemental analysis, DSC and TGA, SAXS, WAXS and XRD studies. The incorporation of the metal-containing complex directly into the polymer chain results in an excellent tensile strength (122 MPa) and modulus of elasticity (4.3 GPa) of the obtained films. The resulting copolymers demonstrated self-healing properties both at acidic pH (assisted by HCl healing) with effective preservation of mechanical properties, and autonomously in a humid atmosphere at room temperature without the use of initiators. At the same time, with a decrease in the content of acrylamide, a decrease in the reducing properties was observed, possibly due to an insufficient amount of amide groups to form hydrogen bonds through the interface with terminal carboxyl groups, as well as a decrease in the stability of complexes in samples with a high content of acrylic acid. Full article
(This article belongs to the Special Issue Coordination Polymers: Properties and Applications II)
Show Figures

Graphical abstract

13 pages, 3748 KiB  
Article
Self-Healing Glass/Metakaolin-Based Geopolymer Composite Exposed to Molten Sodium Chloride and Potassium Chloride
by Patrick F. Keane, Rhys Jacob, Martin Belusko and Frank Bruno
Appl. Sci. 2023, 13(4), 2615; https://doi.org/10.3390/app13042615 - 17 Feb 2023
Cited by 6 | Viewed by 2447
Abstract
Geopolymers (GP) are a class of X-ray amorphous, nanoporous, nanoparticulate materials that can be mixed, poured, and cured under ambient conditions. Typically, geopolymers are made using a Group 1 (G1) alkali activator such as sodium or potassium metasilicate and an aluminosilicate precursor. An [...] Read more.
Geopolymers (GP) are a class of X-ray amorphous, nanoporous, nanoparticulate materials that can be mixed, poured, and cured under ambient conditions. Typically, geopolymers are made using a Group 1 (G1) alkali activator such as sodium or potassium metasilicate and an aluminosilicate precursor. An analogous material to GPs is ordinary Portland cement because of the similarities in processing, however, the resulting microstructure is more similar to that of a glass. Geopolymers are more thermally stable than OPC and can therefore be used in a variety of thermal energy storage systems, as energy storage is an increasing global concern. In this study, potassium metakaolin-based geopolymer composites containing glass particles and alumina platelets were manufactured, heated in air, and exposed to molten sodium chloride or potassium chloride under an air atmosphere. Results showed the formation of an amorphous self-healing geopolymer composite (ASH-G) that could contain molten G1 chlorides for over 200 h without signs of macro or microscopic chemical degradation. The filling of cracks by glass particles in the composite after heating to 850 °C makes this material self-healing. It was found that the morphology of ASH-G composites was more affected by temperature and duration than contact with corrosive molten chlorides in air. Future works include investigating the effect of molten salt on mechanical properties during initial heating, after prolonged heating, and the material compatibility with other molten Group 1 chloride eutectics. Full article
(This article belongs to the Special Issue Alkali-Activated Materials: Advances and Novel Applications)
Show Figures

Figure 1

Back to TopTop