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.

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 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.

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.

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.

Recent Patents on the Structure of Medical Endoscope

2021 ◽  
Vol 15 ◽  
Author(s):  
Yu-Dong Bao ◽  
Kai Li ◽  
Dong-Bo Qi ◽  
Wei Wen ◽  
He-Jun Liu
Keyword(s):  
Medical Equipment ◽  
Rapid Development ◽  
Development Trend ◽  
Future Research ◽  
Medical Endoscope ◽  
Practical Applications ◽  
Mechanical Structure ◽  
The Core ◽  
Core Components ◽  
Further Development

Background: Among the core components of Medical Equipment, the Medical Endoscope is the core functional component of medical equipment, which has become the key research around the world. Objective: By comparing and discussing the patents of the medical endoscope, some valuable conclusions have been drawn to predict the future research and development of the Medical Endoscope. Methods: By analyzing the patent features of the medical endoscope in the mechanical structure, image display, and endoscope system, the function of the medical endoscope on the detection of human internal tissues has been explained. In combination with the key technology of the Medical Endoscope, patents related to the medical endoscope have been studied. Results: With the rapid development of technology in the medical industry and the need for practical applications, there is an increase in the requirements for medical endoscopes. Medical endoscopes have carried out a lot of innovations in mechanical structure, image imaging, and endoscope systems. By comparing the characteristics of various patents of medical endoscopes, the main problems of current medical endoscopes, such as complicated structure and poor lighting imaging effect, are analyzed and summarized. The further development trend of medical endoscopes has also been discussed. Conclusion: By improving and optimizing the mechanical structure of the medical endoscope, the lighting method and the three directions of the system, the performance of the medical endoscope can be improved, the loopholes in the current technology can be solved, and it will be more practical.

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 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.

scholarly journals Preparation and Characterization of Microencapsulated Ethylenediamine with Epoxy Resin for Self-healing Composites

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Liye Yuan ◽  
Tongqing Sun ◽  
Honglin Hu ◽  
Shuxia Yuan ◽  
Yu Yang ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Interfacial Polymerization ◽  
Silicone Oil ◽  
Optical Microscope ◽  
Self Healing ◽  
Scanning Calorimetry ◽  
Oil Emulsion ◽  
Factors Affecting ◽  
Healing Agent ◽  
Water In Oil Emulsion

AbstractHealing agent microcapsules have been used to realize self-healing for polymeric composites. In this work a novel kind of microcapsules encapsulating ethylenediamine (EDA) with epoxy resin as shell material were prepared by interfacial polymerization technology. The oil phase was epoxy resin prepolymer and carbon tetrachloride, and the water phase was EDA and deionized water. Under the action of emulsifier, a stable water-in-oil emulsion was formed. Then the emulsion was added to dimethyl silicone oil, stirred and dispersed, to prepare microcapsules. In addition, the factors affecting the preparation of microcapsules were studied. In this study, Fourier transform infrared(FTIR) was carried out to demonstrate the chemical structure of ethylenediamine microcapsules. Optical microscope(OM) and scanning electron microscope(SEM) were used to observe the morphology of microcapsules. Thermogravimetric analysis and differential scanning calorimetry were done to investigate the thermal properties of microcapsules. Permeability experiment and isothermal aging test were executed to verify the environment resistance of microcapsules. Results showed that EDA was successfully coated in epoxy resin and the microcapsule size was in the range of 50~630 μm. The synthesized microcapsules were thermally stable below 75 °C and perfect permeability resistance to ethanol solvent.

scholarly journals Fabrication and Property Regulation of Small-Size Polyamine Microcapsules via Integrating Microfluidic T-Junction and Interfacial Polymerization

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1800
Author(s):  
Shaochuan Lai ◽  
Yongjun He ◽  
Daoying Xiong ◽  
Yao Wang ◽  
Kaibin Xiao ◽  
...  
Keyword(s):  
Interfacial Polymerization ◽  
Monomer Concentration ◽  
The Self ◽  
Self Healing ◽  
Core Content ◽  
Epoxy Amine ◽  
Healing System ◽  
Application Potential ◽  
Size Restriction ◽  
Shell Forming

The self-healing system based on microencapsulated epoxy-amine chemistry is currently the self-healing system with the most practical application potential. It can be widely used in many epoxy-based materials with a size restriction for the microcapsules, such as fiber-reinforced composites, anti-corrosion coatings, etc. Although epoxy microcapsules of different sizes can be fabricated using different techniques, the preparation of polyamine microcapsules with suitable sizes and good performance is the prerequisite for further developing this self-healing system. In this investigation, based on the novel microencapsulation technique via integrating microfluidic T-junction and interfacial polymerization, the feasibility of preparing small-size polyamine microcapsules and the process regulation to optimize the properties of the small-size microcapsules were studied. We show that polyamine microcapsules with sizes smaller than 100 μm can be obtained through the T-junction selection and the feeding rate control of the polyamine. To regulate the small-size microcapsules’ quality, the effects of the concentration of the shell-forming monomer and the solvent with different polarity in the reaction solution and the reaction condition were studied. It shows that dry, free-flowing small-size microcapsules can still be obtained when the shell-forming monomer concentration is higher and the solvent’s polarity is lower, compared with the preparation of larger polyamine microcapsules. Although the change of reaction conditions (reaction temperature and duration) has a certain effect on the microcapsules’ effective core content, it is relatively small. The results of this investigation further promote the potential application of the self-healing systems based on microencapsulated epoxy-amine chemistry in materials with a size restriction for the microcapsules.

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