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.

scholarly journals Self-Healable Supramolecular Vanadium Pentoxide Reinforced Polydimethylsiloxane-Graft-Polyurethane Composites

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 41 ◽  
Author(s):  
Ali Berkem ◽  
Ahmet Capoglu ◽  
Turgut Nugay ◽  
Erol Sancaktar ◽  
Ilke Anac
Keyword(s):  
Tensile Strength ◽  
Vanadium Pentoxide ◽  
Coupling Reaction ◽  
Optical Microscope ◽  
Mechanical Tests ◽  
Healing Time ◽  
The Self ◽  
Supramolecular Polymer ◽  
Self Healing ◽  
Healing Efficiency

The self-healing ability can be imparted to the polymers by different mechanisms. In this study, self-healing polydimethylsiloxane-graft-polyurethane (PDMS-g-PUR)/Vanadium pentoxide (V2O5) nanofiber supramolecular polymer composites based on a reversible hydrogen bonding mechanism are prepared. V2O5 nanofibers are synthesized via colloidal route and characterized by XRD, SEM, EDX, and TEM techniques. In order to prepare PDMS-g-PUR, linear aliphatic PUR having one –COOH functional group (PUR-COOH) is synthesized and grafted onto aminopropyl functionalized PDMS by EDC/HCl coupling reaction. PUR-COOH and PDMS-g-PUR are characterized by 1H NMR, FTIR. PDMS-g-PUR/V2O5 nanofiber composites are prepared and characterized by DSC/TGA, FTIR, and tensile tests. The self-healing ability of PDMS-graft-PUR and composites are determined by mechanical tests and optical microscope. Tensile strength data obtained from mechanical tests show that healing efficiencies of PDMS-g-PUR increase with healing time and reach 85.4 ± 1.2 % after waiting 120 min at 50 °C. The addition of V2O5 nanofibers enhances the mechanical properties and healing efficiency of the PDMS-g-PUR. An increase of healing efficiency and max tensile strength from 85.4 ± 1.2% to 95.3 ± 0.4% and 113.08 ± 5.24 kPa to 1443.40 ± 8.96 kPa is observed after the addition of 10 wt % V2O5 nanofiber into the polymer.

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.

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.

scholarly journals Preparation of Microcapsules of Urea Formaldehyde Resin Coated Waterborne Coatings and Their Effect on Properties of Wood Crackle Coating

Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 764 ◽  
Author(s):  
Xiaoxing Yan ◽  
Wenwen Peng
Keyword(s):  
In Situ Polymerization ◽  
Urea Formaldehyde ◽  
Impact Resistance ◽  
Acrylic Resin ◽  
Chromatic Aberration ◽  
Protective Role ◽  
The Self ◽  
Formaldehyde Resin ◽  
Self Healing ◽  
The Core

Urea formaldehyde coated waterborne acrylic resin microcapsules with core-wall ratios of 0.30, 0.45, 0.60, 0.67, and 0.75, and mass fractions of 1.0%, 4.0%, 7.0%, 10.0%, 13.0%, and 16.0% were prepared by in situ polymerization. Their micro morphology was examined by scanning electron microscope and infrared spectrum measurements. The gloss, color difference, adhesion, hardness, and impact resistance of the coating surface were investigated in detail. The influence of the core-wall ratio on the performance of the waterborne crackle coating on the wood surface and the self-healing performance were examined. The results showed that when the core-wall ratio of microcapsules was 0.67, an evenly dispersed powder state with particle size of about 3 μm microcapsules was obtained, and the highest coverage was achieved. When the mass fraction of the microcapsule was 4.0%, it had the optimum effect on surface performance. The adhesion was grade two, gloss was 10.9%, impact resistance was 15 kg·cm, chromatic aberration was 1.0, hardness was H, and it had the best effect on the healing of microcracks in the wood coating. As the coating added with microcapsules can inhibit the microcracks of the coating and plays a protective role for the substrate to achieve a self-healing effect, this study lays a technical foundation for the self-healing of surface cracks in coatings for wood.

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

scholarly journals A Self-healing Hydrogel Electrolyte Towards All-in-one Flexible Supercapacitors

2021 ◽  
Author(s):  
Wen-Bin Ma ◽  
Ke-Hu Zhu ◽  
Shi-Fang Ye ◽  
Yao Wang ◽  
Lin Guo ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Mechanical Performance ◽  
In Situ Polymerization ◽  
The Self ◽  
Poly Vinyl Alcohol ◽  
Physical Interaction ◽  
Self Healing ◽  
Wearable Electronics ◽  
Pva Hydrogel

Abstract The autonomously self-healable all-in-one supercapacitor is prepared by in situ rapid polymerization of electrode materials on the surface of self-healing poly (vinyl alcohol) (PVA) hydrogel electrolyte containing sulphuric acid (H2SO4). The self-healing PVA electrolyte has been achieved by physical interaction, in which dynamic hydrogen bonds between PVA chains can readily break and reform, allowing PVA hydrogel electrolyte to self-heal and regain its mechanical and electrochemical properties. The obtained PVA hydrogel displays fast self-healing capability, reliable mechanical performance (stress at 290 KPa after stretching to 238 %) and high ionic conductivity (57.8 mS cm− 1). Based on these excellent properties, an all-in-one supercapacitor with self-healing characteristics is assembled by in situ polymerization of aniline on the surface of self-healable PVA electrolyte. The self-healable all-in-one supercapacitor exhibits specific capacitance 470 mF cm− 2 at current density of 0.2 mA cm− 2 and energy density 32 µWh cm− 2 at power density 100 µW cm− 2. The broken device can be repaired itself and there is a 63% capacitance retention for the healable supercapacitor. This self-healing supercapacitor will promote the development of self-healing energy storage devices in wearable electronics.

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

A MICROCAPSULE TECHNOLOGY BASED SELF-HEALING SYSTEM FOR CONCRETE STRUCTURES

2013 ◽  
Vol 07 (03) ◽  
pp. 1350014 ◽  
Author(s):  
BIQIN DONG ◽  
NINGXU HAN ◽  
MING ZHANG ◽  
XIANFENG WANG ◽  
HONGZHI CUI ◽  
...  
Keyword(s):  
Urea Formaldehyde ◽  
Concrete Structures ◽  
The Self ◽  
Polymerization Reaction ◽  
Formaldehyde Resin ◽  
Self Healing ◽  
Cementitious Composite ◽  
Healing System ◽  
Healing Efficiency ◽  
Healing Agent

In the study, a novel microcapsule technology based self-healing system for concrete structures has been developed. Through situ-polymerization reaction, the microcapsule is formed by urea formaldehyde resin to pack the epoxy material, which is applied to cementitious composite to achieve self-healing effect. The experimental results revealed that the self-healing efficiency of the composite can be accessed from the recovery of the permeability and strength for the cracked cementitious specimens as the healing agent in the microcapsule acting on the cracks directly. Scanning electronic microscope (SEM/EDX) results show that the epoxy resin is released along with the cracking of the cementitious composite and prevent from cracks continued growth. Further studies show that the self-healing efficiency is affected by the pre-loading of composite, particle size of microcapsule, aging duration of healing agent and so on.

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.

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.

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