Mechanical Properties of Self-Healing System in Cementitious Material with Microcapsule

2018 ◽  
Vol 913 ◽  
pp. 1090-1096 ◽  
Author(s):  
Peng Liang ◽  
Qian Jin Mao ◽  
Zi Ming Wang ◽  
Su Ping Cui
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
In Situ Polymerization ◽  
Urea Formaldehyde ◽  
Strength Loss ◽  
Cementitious Materials ◽  
Self Healing ◽  
Healing System ◽  
The Matrix

In this paper, several urea–formaldehyde/epoxy microcapsules with different particle sizes were synthesized by in-situ polymerization. The chemical structure and compressive rupture load of microcapsule were characterized. The effect of microcapsule dosage, particle size and preload pressure on compressive strength of cementitious materials was studied. The result shows: when the particle size of microcapsule is 2 mm~2.5 mm, the rupture load of microcapsule is highest, more than 3N; When the microcapsule dosage is less than 2.5%, the strength loss of the matrix is relatively small; With the increase of the particle size of the capsule, the strength of the matrix decrease greatly; When the dosage of microcapsule is 2.5%, the particle size is 1.5 mm and the preload pressure is 30%~45%fmax, the compressive strength of the self-healing specimen is 8% higher than that of the non-preloaded specimens, which shows a certain self-healing performance.

Preparation and Characterization of Hexadecane Microcapsule Phase Change Materials by In Situ Polymerization

2013 ◽  
Vol 815 ◽  
pp. 367-370 ◽  
Author(s):  
Xiao Qiu Song ◽  
Yue Xia Li ◽  
Jing Wen Wang
Keyword(s):  
Particle Size ◽  
Phase Change ◽  
Phase Change Materials ◽  
In Situ Polymerization ◽  
Urea Formaldehyde ◽  
Agitation Speed ◽  
Urea Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Mass Ratio

Hexadecane microcapsule phase change materials were prepared by the in-situ polymerization method using hexadecane as core materials, urea-formaldehyde resin and urea-formaldehyde resin modified with melamine as shell materials respectively. Effect of melamine on the properties of microcapsules was studied by FTIR, biomicroscopy (UBM), TGA and HPLC. The influences of system concentration, agitation speed and mass ratio of wall to core were also investigated. The results indicated that hexadecane was successfully coated by the two types of shell materials. The addition of melamine into the urea-formaldehyde resin microcapsule reduced microcapsule particle size and microencapsulation efficiency. The influences of factors such as system concentration, agitation speed and mass ratio of wall to core to different wall materials microcapsules presented different variety trends of the microcapsule particle size.

scholarly journals Self-Healing EPDM Rubbers with Highly Stable and Mechanically-Enhanced Urea-Formaldehyde (UF) Microcapsules Prepared by Multi-Step In Situ Polymerization

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1918 ◽  
Author(s):  
Hyeong-Jun Jeoung ◽  
Kun Won Kim ◽  
Yong Jun Chang ◽  
Yong Chae Jung ◽  
Hyunchul Ku ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
In Situ Polymerization ◽  
Urea Formaldehyde ◽  
Testing Machine ◽  
Optical Microscope ◽  
The Self ◽  
Self Healing ◽  
Grubbs Catalyst ◽  
Healing Efficiency

The mechanically-enhanced urea-formaldehyde (UF) microcapsules are developed through a multi-step in situ polymerization method. Optical microscope (OM) and field emission scanning electron microscope (FE-SEM) prove that the microcapsules, 147.4 μm in diameter with a shell thickness of 600 nm, are well-formed. From 1H-nuclear magnetic resonance (1H-NMR) analysis, we found that dicyclopentadiene (DCPD), a self-healing agent encapsulated by the microcapsules, occupies ca. 40.3 %(v/v) of the internal volume of a single capsule. These microcapsules are mixed with EPDM (ethylene-propylene-diene-monomer) and Grubbs’ catalyst via a solution mixing method, and universal testing machine (UTM) tests show that the composites with mechanically-enhanced microcapsules has ca. 47% higher toughness than the composites with conventionally prepared UF microcapsules, which is attributed to the improved mechanical stability of the microcapsule. When the EPDM/microcapsule rubber composites are notched, Fourier-transform infrared (FT-IR) spectroscopy shows that DCPD leaks from the broken microcapsule to the damaged site and flows to fill the notched valley, and self-heals as it is cured by Grubbs’ catalyst. The self-healing efficiency depends on the capsule concentration in the EPDM matrix. However, the self-healed EPDM/microcapsule rubber composite with over 15 wt% microcapsule shows an almost full recovery of the mechanical strength and 100% healing efficiency.

Self-Healing of Cracks in Epoxy Composites

2008 ◽  
Vol 47-50 ◽  
pp. 282-285 ◽  
Author(s):  
Tao Yin ◽  
Min Zhi Rong ◽  
Ming Qiu Zhang
Keyword(s):  
Urea Formaldehyde ◽  
Epoxy Composites ◽  
Glass Fabric ◽  
Self Healing ◽  
Plain Weave ◽  
Composites Manufacturing ◽  
Healing System ◽  
Two Component ◽  
The Matrix

To provide epoxy based composites with self-healing ability, two-component healing system consisting of urea-formaldehyde walled microcapsules containing epoxy (30~70µm in diameter) and CuBr2(2-MeIm)4 (the complex of CuBr2 and 2-methylimidazole) latent hardener was synthesized. When cracks were initiated or propagated in the composites, the neighbor micro-encapsulated epoxy would be damaged and released. As the latent hardener is soluble in epoxy, it can be well dispersed in epoxy composites during composites manufacturing, and hence activate the released epoxy wherever it is. As a result, repair of the cracked sites is completed through curing of the released epoxy. The present work indicated that the plain weave glass fabric laminates using the above self-healing epoxy as the matrix have been provided with self-healing capability.

scholarly journals Green synthesis of nanocapsules for self-healing anticorrosion coating using ultrasound-assisted approach

2018 ◽  
Vol 7 (2) ◽  
pp. 147-159 ◽  
Author(s):  
Uday D. Bagale ◽  
Shirish H. Sonawane ◽  
Bharat A. Bhanvase ◽  
Ravindra D. Kulkarni ◽  
Parag R. Gogate
Keyword(s):  
Corrosion Inhibition ◽  
Electrochemical Impedance ◽  
In Situ Polymerization ◽  
Urea Formaldehyde ◽  
Immersion Test ◽  
Epoxy Coating ◽  
Self Healing ◽  
Actual Performance ◽  
Ultrasound Assisted

Abstract The present work deals with the production of nanocapsules containing a natural corrosion inhibition component. Azadirachta indica was encapsulated in urea-formaldehyde polymeric shell using ultrasound-assisted and conventional approaches of in situ polymerization. Subsequently nanocapsules were incorporated into clear epoxy polyamide to develop the green self-healing corrosion inhibition coating. The actual performance of the coating was evaluated based on the studies involving the repair of the crack of high solid surface coating. Corrosion inhibition of the healed area has been evaluated using the electrochemical impedance spectroscopy and immersion test based on the use of standard epoxy coating. The obtained results confirmed better corrosion protection in terms of the electrochemical impendence spectroscopy data and Tafel plot. It was found that current density decreases from 0.0011 A/cm2 (for standard epoxy coating) to 5.22 E−7 A/cm2 as 4 wt% nanocapsules incorporated in coating.

Self-healing coatings based on poly(urea-formaldehyde) microcapsules: In situ polymerization, capsule properties and application

2021 ◽  
Vol 161 ◽  
pp. 106475
Author(s):  
Christos Zotiadis ◽  
Ioannis Patrikalos ◽  
Vasileia Loukaidou ◽  
Dimitrios M. Korres ◽  
Antonis Karantonis ◽  
...  
Keyword(s):  
In Situ Polymerization ◽  
Urea Formaldehyde ◽  
Self Healing

Particle Size Effect on the Corona Resistant Properties of PI/TiO2 Composite Films

2014 ◽  
Vol 981 ◽  
pp. 914-917
Author(s):  
Guang You Li ◽  
Jing Hua Yin ◽  
Lei Yao ◽  
Xing Zhao
Keyword(s):  
Particle Size ◽  
In Situ Polymerization ◽  
Composite Films ◽  
Particle Size Effect ◽  
Interface Layer ◽  
Nanocomposite Films ◽  
Particle Sizes ◽  
Small Particles ◽  
The Matrix

Polyimide-based (PI) nanocomposites possess excellent electrical and thermal performance, widely used in inverter motor. In the paper using different particle sizes made polyimide/titania (PI/TiO2) nanocomposite films in situ polymerization, including 20nm A series and 50nm B series. The results shows that A series have a larger specific surface, combination of the film and matrix is closer without affecting the imidization of PI, and there is a clear interface layer and the structure is more stable. According to the time of corona-resistant A Series films is significantly longer than B Series films, especially the A series films with 15% of which corona-resistant time is 15h, five times than the pure PI. By both SAXS and XRD particle size in the matrix can be calculated, proving small particles can be better combination of the matrix of PI, increasing the number of traps, more effectively cutting off charge corrosion and making corona resistance greater performance.

Epoxy loaded poly(urea‐formaldehyde) microcapsules via in situ polymerization designated for self‐healing coatings

2020 ◽  
Vol 137 (43) ◽  
pp. 49323 ◽  
Author(s):  
Sofia Tzavidi ◽  
Christos Zotiadis ◽  
Athanasios Porfyris ◽  
Dimitrios M. Korres ◽  
Stamatina Vouyiouka
Keyword(s):  
In Situ Polymerization ◽  
Urea Formaldehyde ◽  
Self Healing

The Effects of Synthesis Conditions on PUF Microcapsule Morphology

2012 ◽  
Vol 217-219 ◽  
pp. 661-665
Author(s):  
Ning Ning Hu ◽  
Hao Han Huang ◽  
Hong Zhi Cui
Keyword(s):  
Particle Size ◽  
In Situ Polymerization ◽  
Average Particle Size ◽  
Wall Material ◽  
Average Particle ◽  
Self Healing ◽  
Test Results ◽  
Synthesis Conditions ◽  
Wide Range

In this paper, self-healing PUF microcapsules were prepared by in situ polymerization. The test results show that: 1) the ratio of core/wall material can had a significant effect on the average particle size of microcapsules. The ratio happens to be 1.0 to 1.0, best coating, relatively dense surface can be achieved. When the ratio reaches 1.4 to 1.0, the microcapsules have worst coating, particle size, distribution of wide range, and comparatively rough surface. When the ratio is 0.8 to 1.0 or 1.2 to 1.0, preferable coating, uniform particle size and its distribution, as well as smooth and dense surface can be obtained. 2) The faster the stirring speed, the smaller the particle size of microcapsule will be. And the size becomes bigger and varied with the stirring speed decreasing.

Preparation and Characterization of Microcapsules for Self-Healing Material

2012 ◽  
Vol 430-432 ◽  
pp. 960-963 ◽  
Author(s):  
Wan Peng Ma ◽  
Wei Zhang ◽  
Yang Zhao ◽  
Le Ping Liao ◽  
Si Jie Wang
Keyword(s):  
In Situ Polymerization ◽  
Urea Formaldehyde ◽  
Self Healing ◽  
Water Emulsion ◽  
Good Thermal Stability ◽  
Oil In Water ◽  
Inner Surface ◽  
Oil In Water Emulsion

Urea-formaldehyde microcapsules containing epoxy resin is a promising material for self-healing design. The microcapsules were prepared by in-situ polymerization in an oil-in-water emulsion. The microcapsule formation process was monitored using optical microscopy. Surface morphology was observed using field emission scanning electron microscopy. The thermal property of microcapsules was characterized using thermogravimetric analysis. The results indicate that microcapsule wall has a rough outer surface and a smooth inner surface. The microcapsule size is controlled by different agitation rates. Microcapsules have a good thermal stability below 157°C.

scholarly journals Influencing Factors on the Healing Performance of Microcapsule Self-Healing Concrete

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4139
Author(s):  
Yanju Wang ◽  
Zhiyang Lin ◽  
Can Tang ◽  
Wenfeng Hao
Keyword(s):  
Compressive Strength ◽  
Sodium Silicate ◽  
Recovery Rate ◽  
Sound Speed ◽  
Orthogonal Experimental Design ◽  
Self Healing ◽  
Damage Degree ◽  
Strength Recovery ◽  
Healing System ◽  
Recovery Performance

The amounts of the components in a microcapsule self-healing system significantly impact the basic performance and self-healing performance of concrete. In this paper, an orthogonal experimental design is used to investigate the healing performance of microcapsule self-healing concrete under different pre-damage loads. The strength recovery performance and sound speed recovery performance under extensive damage are analyzed. The optimum factor combination of the microcapsule self-healing concrete is obtained. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) are carried out on the concrete samples before and after healing to determine the healing mechanism. The results show that the healing effect of self-healing concrete decreases with an increase in the pre-damage load, and the sound speed recovery rate increases with an increase in the damage degree. The influence of the sodium silicate content on the compressive strength and compressive strength recovery rate of the self-healing concrete increases, followed by a decrease. The optimum combination of factors of the microcapsule self-healing system is 3% microcapsules, 30% sodium silicate, and 15% sodium fluosilicate. The results can be used for the design and preparation of self-healing concrete.

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