scholarly journals Preparation and Characterization of Nano-CaCO3/Ceresine Wax Composite Shell Microcapsules Containing E-44 Epoxy Resin for Self-Healing of Cement-Based Materials

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 197
Author(s):  
Wei Du ◽  
Erwang Li ◽  
Runsheng Lin
Keyword(s):  
Epoxy Resin ◽  
Recovery Rate ◽  
Composite Shell ◽  
Chloride Ion ◽  
Self Healing ◽  
The Core ◽  
Core Content ◽  
Cement Based Materials ◽  
Healing Agent ◽  
Melt Condensation

As an intelligent material, microcapsules can efficiently self-heal internal microcracks and microdefects formed in cement-based materials during service and improve their durability. In this paper, microcapsules of nano-CaCO3/ceresine wax composite shell encapsulated with E-44 epoxy resin were prepared via the melt condensation method. The core content, compactness, particle size distribution, morphologies, chemical structure and micromechanical properties of microcapsules were characterized. The results showed that the encapsulation ability, mechanical properties and compactness of microcapsules were further improved by adding nano-CaCO3 to ceresine wax. The core content, elastic modulus, hardness and weight loss rate (60 days) of nano-CaCO3/ceresine wax composite shell microcapsules (WM2) were 80.6%, 2.02 GPA, 72.54 MPa and 1.6%, respectively. SEM showed that WM2 was regularly spherical with a rough surface and sufficient space inside the microcapsules to store the healing agent. The incorporation of WM2 to mortar can greatly improve the self-healing ability of mortar after pre-damage. After 14 days of self-healing, the compressive strength recovery rate, proportion of harmful pores and chloride ion diffusion coefficient recovery rate increased to 90.1%, 45.54% and 79.8%, respectively. In addition, WM2 also has good self-healing ability for mortar surface cracks, and cracks with initial width of less than 0.35 mm on the mortar surface can completely self-heal within 3 days.

Comparative Study on Microencapsulated of Natural and Waste Sunflower Oil as Self-Healing Agent

2020 ◽  
Vol 1010 ◽  
pp. 439-444
Author(s):  
Zulkhibri Baharom ◽  
Maizlinda Izwana Idris ◽  
Tee Chuan Lee ◽  
Hasan Zuhudi Abdullah
Keyword(s):  
Sunflower Oil ◽  
Raw Materials ◽  
Metal Coating ◽  
Natural Material ◽  
Self Healing ◽  
Micro Structure ◽  
The Core ◽  
Core Content ◽  
Healing Agent ◽  
Alternative Resource

Microencapsulation of natural vegetable oil as a self-healing agent on metal coating became demanded lately. This paper underlines the microcapsule containing natural and wastes sunflower oil as a self-healing agent that was fabricated for the backbone of corrosion coatings. The results in this paper indicated the distinguished potential of waste sunflower oil as compared to natural sunflower oil. The diameter of microcapsules synthesized from natural sunflower oil and waste sunflower oil both in range of 3-4 µm. The shell of microcapsules microencapsulated from natural sunflower oil showed rough micro-structure while the shell of microcapsules microencapsulated from waste sunflower oil showed smooth micro-structure. The main parameter studied in this research was the varient of stirring speed during the process of microencapsulation. The involvement of stirring speed starts from 200 to 400 rpm. The microcapsules undergo varient of stirring speed analyzed on the yield and core content of microcapsules. The microcapsules from natural produced 29-50% while waste resources bring 26-48% of yield productions. The core content of microencapsulated natural sunflower oil generates 55-64% core content as comparing with waste sources which produce 56-67% of core content. It can be concluded that it was proved that sunflower oil could be considered as an alternative resource for self-healing agent in metal coating either encapsulated from natural or waste raw materials. The incorporation of green and natural material as a self-healing agent significantly influences the sustaining the environment to the safest stage.

Synthesis and Self-Healing Mechanism of Self-Healing Epoxy Microcapsule Materials

2020 ◽  
Vol 842 ◽  
pp. 3-9
Author(s):  
Zhuo Ni ◽  
Zhen Guo ◽  
Yu Hao Lin
Keyword(s):  
Epoxy Resin ◽  
Interfacial Polymerization ◽  
Curing Temperature ◽  
Future Research ◽  
Self Healing ◽  
Practical Applications ◽  
The Core ◽  
Good Surface ◽  
Core Content ◽  
Wall Materials

Self-healing epoxy resin microcapsules are prepared by interfacial polymerization, in which the core materials are epoxy resin, the wall materials are constructed with triethylenetetramine and the epoxy resin. The orthogonal experimental L9(34) are designed to investigate the influence of emulsifier dosage, hardener dosage, curing temperature and hardener adding rate on the core content and storage life of epoxy resin microcapsule. Scanning electron microscope is used to characterize surface topography and distribution. Fourier transform infrared spectroscopy is used to study reaction mechanism of the microcapsule wall materials, respectively. The results indicate that when the dosage of emulsifier is 1.2%, the dosage of hardener is 1.2%, the hardener droplets adding rate is 1.2 g/h and the curing temperature is 50°C, the prepared microcapsules with a high level of core content are spherical in shape with good surface compactness and dispersibility. Future research may focus on improving microcapsule storage stability and the obstacles encountered in practical applications.

scholarly journals Preparation and Characterization of Microcrystalline Wax/Epoxy Resin Microcapsules for Self-Healing of Cementitious Materials

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1725
Author(s):  
Wei Du ◽  
Quantao Liu ◽  
Runsheng Lin ◽  
Xin Su
Keyword(s):  
Epoxy Resin ◽  
Size Distribution ◽  
Weight Ratio ◽  
Cementitious Materials ◽  
Self Healing ◽  
Surface Cracks ◽  
Preparation Temperature ◽  
Core Content ◽  
Healing Agent

Self-healing of cracks in cementitious materials using healing agents encapsulated in microcapsules is an intelligent and effective method. In this study, microcapsules were prepared by the melt–dispersion–condensation method using microcrystalline wax as the shell and E-51 epoxy resin as the healing agent. The effects of preparation process parameters and microcrystalline wax/E-51 epoxy resin weight ratio on the core content, particle size distribution, thermal properties, morphology, and chemical composition of microcapsules were investigated. The results indicated that the optimal parameters of the microcapsule were microcrystalline wax/E-51 epoxy resin weight ratio of 1:1.2, stirring speed of 900 rpm, and preparation temperature of 105 °C. The effects of microcapsules on pore size distribution, pore structure, mechanical properties, permeability, and ultrasonic amplitude of mortar were determined, and the self-healing ability of mortar with different contents of microcapsules was evaluated. The optimal content of microcapsules in mortars was 4% of the cement weight, and the surface cracks of mortar containing microcapsules with an initial width of 0.28 mm were self-healed within three days, indicating that microcapsules have excellent self-healing ability for cementitious materials.

scholarly journals SYNTHESIS OF MICROCAPSULES FROM PREPOLYURETHANES

2018 ◽  
Vol 55 (1B) ◽  
pp. 138
Author(s):  
Ha La Thi Thai
Keyword(s):  
Interfacial Polymerization ◽  
Gum Arabic ◽  
Chain Extender ◽  
Toluene Diisocyanate ◽  
Agitation Rate ◽  
Self Healing ◽  
The Core ◽  
Core Content ◽  
Oil In Water ◽  
Healing Agent

Polyurethane (PU) microcapsules containing toluene diisocyanate (TDI) healing agent were synthesized by mixing PU with chain extender ethyleneglycol (EG) via interfacial polymerization of oil–in–water (gum arabic emulsifier). The morphology and size of the capsules greatly depend on a variety of factors including dispersion speed and emulsifier ratio. The preparation of PU prepolymer and microcapsulation of TDI are presented. The diameter of smooth spherical microcapsules ranged from 93, 160 and 239 µm are produced by varying the agitation rate from 800 rpm to 1200 rpm. The core content of microcapsules is influenced by the ratio of chlorobenzene (CB) solvent in oil phase. The microcapsules have about 40.5 wt% of core which are capable of application in self–healing coatings when using 20 wt% CB and 17.5 wt% emulsifer ratio.

Self-Healing Epoxy Coating Modified by Double-Walled Microcapsules Based Polyurea for Metallic Protection

2019 ◽  
Vol 821 ◽  
pp. 313-320
Author(s):  
Yan Xuan Ma ◽  
Ying Rui Zhang ◽  
Jia Tong Liu ◽  
Meng Yao Li ◽  
Ya Qian Xu
Keyword(s):  
Chemical Structure ◽  
Interfacial Polymerization ◽  
Electrochemical Impedance ◽  
Self Healing ◽  
High Corrosion Resistance ◽  
Hexamethylene Diamine ◽  
Thermogravimetric Analyzer ◽  
The Core ◽  
Core Content ◽  
Scanning Electronmicroscopy

The effectiveness of preploymer and 1,6-Hexamethylene diamine encapsulated by double-walled microcapsules based polyurea (PUA) was explored for healing the cracks generated in epoxy coatings. Double-walled microcapsules were systhesized by interfacial polymerization at the interface between the prepolymer droplets and the 1,6-Hexamethylene diamine droplets to form the polyurea shell. The effect of synthetic stirring speed on the morphology of the microcapsules was observed by scanning electronmicroscopy (SEM) and optical microscopy (OM). The chemical structure as well as the thermal properties and the core content were characterized by Fourier transform infrared spectroscopy (FTIR) and Thermogravimetric analyzer (TGA) respectively. Electrochemical impedance spectroscopy (EIS) studies of the artificial scratched area showed that the coating containing 2wt% and 5wt% microcapsules could effectively prevent further corrosion of the coating with high corrosion resistance efficiencies of 61.61% and 45.99% after immersing for 144h in seawater.

scholarly journals Impact of Bio-Carrier Immobilized with Marine Bacteria on Self-Healing Performance of Cement-Based Materials

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4164 ◽  
Author(s):  
Hayeon Kim ◽  
Hyeongmin Son ◽  
Joonho Seo ◽  
H. K. Lee
Keyword(s):  
Mechanical Properties ◽  
Mercury Intrusion Porosimetry ◽  
Tap Water ◽  
Bottom Ash ◽  
Self Healing ◽  
Mixing Process ◽  
Mercury Intrusion ◽  
Healing Efficiency ◽  
Cement Based Materials ◽  
Healing Agent

The present study evaluated the self-healing efficiency and mechanical properties of mortar specimens incorporating a bio-carrier as a self-healing agent. The bio-carrier was produced by immobilizing ureolytic bacteria isolated from seawater in bottom ash, followed by surface coating with cement powder to prevent loss of nutrients during the mixing process. Five types of specimens were prepared with two methods of incorporating bacteria, and were water cured for 28 days. To investigate the healing ratio, the specimens with predefined cracks were treated by applying a wet–dry cycle in three different conditions, i.e., seawater, tap water, and air for 28 days. In addition, a compression test and a mercury intrusion porosimetry analysis of the specimens were performed to evaluate their physico-mechanical properties. The obtained results showed that the specimen incorporating the bio-carrier had higher compressive strength than the specimen incorporating vegetative cells. Furthermore, the highest healing ratio was observed in specimens incorporating the bio-carrier. This phenomenon could be ascribed by the enhanced bacterial viability by the bio-carrier.

Study of Feasibility of Heat Melt Adhesive Being Used in Crack Self-Healing of Cement-Based Materials

2011 ◽  
Vol 99-100 ◽  
pp. 1087-1091 ◽  
Author(s):  
Xiong Zhou Yuan ◽  
Wei Sun ◽  
Xiao Bao Zuo
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Chemical Stability ◽  
Bonding Strength ◽  
Research Team ◽  
Cementitious Materials ◽  
Self Healing ◽  
Detailed Consideration ◽  
Cement Based Materials ◽  
Healing Agent

Based on detailed consideration of the autonomic healing concept of microencapsulated healing agent, micro- bacteria induced calcite and shape memory alloys, our research team proposed a new self-healing technique coupled with of SMA and heat-melt adhesive. In this article, chemical stability and bonding strength with cementitious materials of EVA heat-melt adhesive were tested. Experimental results show that EVA heat-melt adhesive may contain the ability being used in self-healing techniques coupled with SMA.

scholarly journals Preparation and Self-Repairing Properties of Urea Formaldehyde-Coated Epoxy Resin Microcapsules

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Xiaoxing Yan ◽  
Yijuan Chang ◽  
Xingyu Qian
Keyword(s):  
Epoxy Resin ◽  
Deposition Time ◽  
Urea Formaldehyde ◽  
Coverage Rate ◽  
Core Material ◽  
Self Healing ◽  
Mass Ratio ◽  
Repair Rate ◽  
The Core ◽  
Five Factors

Urea formaldehyde resin-coated epoxy resin microcapsules were prepared by two-step in situ polymerization. The effects of five factors on the yield, coverage rate, repair rate, and morphology of the microcapsules were investigated by five factors and four levels of orthogonal test. These five factors were the mass ratio of the core to the wall material (Wcore:Wwall), the mass ratio of the emulsifier to the core material (Wemulsifier:Wcore), stirring rate, deposition time, and mass ratio of the emulsifier solution to the core material (Wemulsifier solution:Wcore). The ideal technological level of microcapsule synthesis was determined. According to the results of the range and variance of yield, coverage rate, and repair rate, the comprehensive properties of microcapsules became ideal. At this time, the Wcore:Wwall was 0.8 : 1, Wemulsifier:Wcore was 1 : 100, stirring rate was 600 r/min, deposition time was 32 h, and Wemulsifier solution:Wcore was 8 : 1. When the concentration of microcapsules in the epoxy resin was 10.0%, the self-repair rate was the best and the repair rate was 114.77%. This study is expected to provide a reference value for the preparation of a microcapsule self-healing technology and lay a foundation for the subsequent development of self-healing materials.

scholarly journals TO/TMMP-TMTGE Double-Healing Composite Containing a Transesterification Reversible Matrix and Tung Oil-Loaded Microcapsules for Active Self-Healing

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1127 ◽  
Author(s):  
Nan Zheng ◽  
Jie Liu ◽  
Wenge Li
Keyword(s):  
Particle Size ◽  
Click Reaction ◽  
Average Particle Size ◽  
Core Shell ◽  
Average Particle ◽  
Self Healing ◽  
Tung Oil ◽  
The Core ◽  
Core Content ◽  
Healing System

Thermoset epoxies are widely used due to their excellent properties, but conventional epoxies require a complicated and time-consuming curing process, and they cannot self-healed, which limits their applications in self-healing materials. Extrinsic and intrinsic self-healing materials are applied in various fields due to their respective characteristics, but there is a lack of comparison between the two types of healing systems. Based on this, a thiol-epoxide click reaction catalyzed by an organic base was introduced to achieve the efficient preparation of thiol-epoxy. Furthermore, tung oil (TO)-loaded microcapsules were introduced into the thiol-epoxy matrix of dynamic transesterification to obtain a TO/TMMP-TMTGE self-healing composite with an intrinsic–extrinsic double-healing system. For comparison, a TMMP-TMTGE self-healing material with an intrinsic healing system was also prepared, which contained only thiol and epoxy curing chemistries. The effect of the core/shell ratio on the morphology, average particle size, and core content of TO-loaded microcapsules was studied. It was found that when the core/shell ratio was 3:1, the average particle size of the microcapsules was about 99.8 μm, and the microcapsules showed good monodispersity, as well as a core content of about 58.91%. The differential scanning calorimetry (DSC) results showed that the TO core was successfully encapsulated and remained effective after encapsulation. Furthermore, scanning electron microscopy (SEM), atomic force microscopy (AFM), tensile tests, and electrochemical tests were carried out for the two types of self-healing materials. The results showed that the TO/TMMP-TMTGE composite and TMMP-TMTGE material both had self-healing properties. In addition, the TO/TMMP-TMTGE composite was superior to the TMMP-TMTGE material due to its better self-healing performance, mechanical strength, and corrosion protection performance.

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