Reusable Self-Healing Hydrogels Realized via in Situ Polymerization

With the development of the embedded microcapsule concept for self-healing material, the preparation of microcapsule has been paid more attentions. A new series of microcapsules were prepared by in situ polymerization technology in an oil-in-water emulsion with polyoxymethylene urea (PMU) as shell material and a mixture of epoxy resins as core material. The PMU microcapsules were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electronic microscopy (SEM), particle size analyzer and thermo gravimetric analyzer (TGA) to investigate their chemical structure, surface morphology, size distribution and thermal stability, respectively. The results indicate that PMU microcapsules containing epoxy resins can be synthesized successfully. The optimized reaction parameters were obtained as follow: agitation rate 600 rpm, 60°C water bath, pH=3.5, core material 20ml and hot water dilution by in-situ polymerization. The size is around 116 μm. The rough outer surface of microcapsule is composed of agglomerated PMU nanoparticles. The microcapsules basically exhibit good storage stability at room temperature, and they are chemically stable before the heating temperature is up to approximately 200°C.

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Multi Self-Healable UV Shielding Polyurethane/CeO2 Protective Coating: The Effect of Low-Molecular-Weight Polyols

Polymers ◽

10.3390/polym12091947 ◽

2020 ◽

Vol 12 (9) ◽

pp. 1947

Author(s):

Mohammad Mizanur Rahman ◽

Rami Suleiman ◽

Md. Hasan Zahir ◽

Aasif Helal ◽

A. Madhan Kumar ◽

...

Keyword(s):

Molecular Weight ◽

In Situ Polymerization ◽

Outdoor Exposure ◽

Low Molecular Weight ◽

Self Healing ◽

Polydimethyl Siloxane ◽

Molecular Weights ◽

Uv Shielding ◽

Ceo2 Coating

We prepared a series of polyurethane (PU) coatings with defined contents using poly(tetramethylene oxide)glycol (PTMG) with two different molecular weights (i.e., Mn = 2000 and 650), as well as polydimethyl siloxane (PDMS) with a molecular weight of Mn 550. For every coating, maximum adhesive strength and excellent self-healing character (three times) were found using 6.775 mol% mixed with low-molecular-weight-based polyols (PU-11-3-3). Defined 1.0 wt% CeO2 was also used for the PU-11-3-3 coating (i.e., PU-11-3-3-CeO2) to obtain UV shielding properties. Both the in situ polymerization and blending processes were separately applied during the preparation of the PU-11-3-3-CeO2 coating dispersion. The in situ polymerization-based coating (i.e., PU-11-3-3-CeO2-P) showed similar self-healing properties. The PU-11-3-3-CeO2-P coating also showed excellent UV shielding in real outdoor exposure conditions.

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

Polymers ◽

10.3390/polym12091918 ◽

2020 ◽

Vol 12 (9) ◽

pp. 1918 ◽

Cited By ~ 1

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.

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Synthesis of robust and self-healing polyurethane/halloysite coating via in-situ polymerization

Journal of Polymer Research ◽

10.1007/s10965-021-02742-4 ◽

2021 ◽

Vol 28 (10) ◽

Author(s):

Changhong Lin ◽

Puyou Ying ◽

Min Huang ◽

Ping Zhang ◽

Tao Yang ◽

...

Keyword(s):

In Situ Polymerization ◽

Self Healing

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The Preparation and Research of Microcapsules in Self-Healing Coatings

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.800.471 ◽

2013 ◽

Vol 800 ◽

pp. 471-475

Author(s):

Wang Rui ◽

Qian Jin Mao ◽

Qi Dong Liu ◽

Xiao Yu Ma ◽

Su Ping Cui ◽

...

Keyword(s):

In Situ Polymerization ◽

Core Material ◽

Agitation Rate ◽

Self Healing ◽

Water Emulsion ◽

Oil In Water ◽

Infrared Spectrometer ◽

Oil In Water Emulsion ◽

The Impact

The self-healing polymer material which was embedded microcapsules possesses the ability to heal cracks automatically. The microcapsules were synthesized by in-situ polymerization in an oil-in-water emulsion with urea and formaldehyde as the raw shell material,and epoxy resin (E-51)/ xylene as the core material. The impact of stirring speed on the morphology and particle size of synthetic microcapsules were discussed by optical microscopy (OM), scanning electron microscopy (SEM), and Fourier-transform infrared spectrometer (FTIR).Microcapsules of 400~1500 um in diameter were produced by appropriate selection of agitation rate in the range of 300~600 r/min.

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Microencapsulation of Styrene/Epoxydiacrylate via In Situ Polymerization of Melamine-Formaldehyde

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.393-395.1279 ◽

2011 ◽

Vol 393-395 ◽

pp. 1279-1282

Author(s):

Hai Ping Wang

Keyword(s):

In Situ Polymerization ◽

Limited Range ◽

Thermoplastic Composites ◽

Resonance Spectroscopy ◽

Self Healing ◽

Melamine Formaldehyde ◽

Core Content ◽

Ft Ir ◽

And Storage

Microcapsules containing the mixture of styrene and epoxydiacrylate (St/E51-AA) for use in self-healing thermoplastic composites were synthesized by in-situ polymerization using melamine-formaldehyde (MF) as shell materials. The microcapsules were prepared in two consecutive steps, emulsification of St/E51-AA in water and then, encapsulation. The chemical structure of microcapsule was identified by Fourier transform infrared spectroscopy (FT-IR) and proton magnetic resonance spectroscopy (1H-NMR), respectively. Morphology and shell wall thickness of microcapsule were observed using scanning electron microscope (SEM). The effect of dispersion rates, through a limited range, was carefully examined on the particle size and core content of microcapsules. It was found that styrene/ epoxydiacrylate-loaded microcapsules were successfully prepared through the proposed technical route, and their mean diameters fell in the range of 36~110 μm. Both core content and microcapsule size can be adjusted by selecting different dispersion rates. The highest loading of St/E51-AA in the resultant microcapsules can be about 85%. In terms of thermogravimetric analysis (TGA), thermal behavior and storage stability of the capsules were studied.

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The Preparation of Microcapsules Used for Self-Healing Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.233-235.2319 ◽

2011 ◽

Vol 233-235 ◽

pp. 2319-2322 ◽

Cited By ~ 2

Author(s):

Ru Tian ◽

Yu Dong Zheng ◽

Xin Liang ◽

Zhang Ming Zhou ◽

Xiao Li Fu ◽

...

Keyword(s):

In Situ Polymerization ◽

Ph Value ◽

Condensation Reaction ◽

Formaldehyde Resin ◽

Self Healing ◽

Mass Ratio ◽

Melamine Formaldehyde ◽

Stirring Rate ◽

The Stability

Microcapsules were prepared by in situ polymerization of melamine-formaldehyde resin to form shell over oxygen resin droplets. Stirring rate, temperature, pH value as well as mass ratio of shell and core are the main parameters affecting the stability of microcapsules. High stirring rate leads to small size of microcapsules. The temperature influences the speed of the reaction and the morphology. The pH value decides whether the condensation reaction can take place. The size of microcapsules is about 15-61um.

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

Green Processing and Synthesis ◽

10.1515/gps-2016-0160 ◽

2018 ◽

Vol 7 (2) ◽

pp. 147-159 ◽

Cited By ~ 9

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.

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.913.1090 ◽

2018 ◽

Vol 913 ◽

pp. 1090-1096 ◽

Cited By ~ 1

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.

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