Fabrication of Polymeric Capsules Enclosing Eletrophoretic Particle Dispersion

2006 ◽  
Vol 949 ◽  
Author(s):  
Ru Qiao ◽  
Xiao Li Zhang ◽  
Ri Qiu ◽  
Yan Li ◽  
Young Soo Kang
Keyword(s):  
In Situ Polymerization ◽  
Urea Formaldehyde ◽  
Optical Microscope ◽  
Control Agent ◽  
Particle Dispersion ◽  
Polymerization Reaction ◽  
Water Emulsion ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Oil In Water Emulsion

ABSTRACTPoly(urea-formaldehyde) capsules enclosing electrophoretic particle dispersion were formed by carrying out an in-situ polymerization reaction in an oil-in-water emulsion. The internal dispersion was composed of pigment particles Yellow-14 modified by charge control agent to have superior electrophoresis velocity and the mixture of tetrachloroethylene and sec-butylbenzene, using Span 80 as the stabilizer and emulsifier. FE-SEM, TEM, and optical microscope (OM) were performed to investigate on the capsule size and surface morphology. Contact angle measurements showed that UF prepolymer deposited at the o/w interface to form hollow capsules only when the interfacial tension is large enough.

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.

Microencapsulation of Epoxy Resins for Self-Healing Material

2010 ◽  
Vol 148-149 ◽  
pp. 1031-1035
Author(s):  
Yang Zhao ◽  
Wei Zhang ◽  
Le Ping Liao ◽  
Wu Jun Li ◽  
Yi Xin
Keyword(s):  
Epoxy Resins ◽  
In Situ Polymerization ◽  
Heating Temperature ◽  
Hot Water ◽  
Core Material ◽  
Agitation Rate ◽  
Self Healing ◽  
Water Emulsion ◽  
Oil In Water Emulsion

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.

Structure and properties of urea-formaldehyde resin/polyurethane blend prepared via in-situ polymerization

RSC Advances ◽  
2015 ◽  
Vol 5 (66) ◽  
pp. 53700-53707 ◽  
Author(s):  
Junling Yuan ◽  
Xiaowen Zhao ◽  
Lin Ye
Keyword(s):  
Energy Dissipation ◽  
In Situ Polymerization ◽  
Microphase Separation ◽  
Urea Formaldehyde ◽  
Urea Formaldehyde Resin ◽  
Polymerization Reaction ◽  
Formaldehyde Resin ◽  
Structure And Properties ◽  
Toughening Mechanism

UF/PU blends with improved toughness were preparedvia in situpolymerization. PU participated in the polymerization reaction of UF. The reaction-induced microphase-separation indicated the energy-dissipation toughening mechanism.

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.

Melamine Resin-Walled Microcapsules Containing Styrene: Preparation and Characterization

2008 ◽  
Vol 47-50 ◽  
pp. 286-289 ◽  
Author(s):  
Hai Ping Wang ◽  
Yan Chao Yuan ◽  
Min Zhi Rong ◽  
Ming Qiu Zhang
Keyword(s):  
In Situ Polymerization ◽  
Weight Ratio ◽  
Processing Parameters ◽  
Optical Microscope ◽  
Resonance Spectroscopy ◽  
Self Healing ◽  
Melamine Formaldehyde ◽  
Scanning Calorimetry ◽  
Water Emulsion ◽  
Core Content

For purposes of developing a novel self-healing chemistry for polymer composites, melamine-formaldehyde (MF) resin-walled microcapsules containing styrene were prepared by in-situ polymerization in an oil-in-water emulsion. Chemical structure of the microcapsules was identified by Fourier-transform infrared spectroscopy (FTIR) and proton magnetic resonance spectroscopy (1H NMR), respectively. In addition, scanning electron microscope (SEM) and optical microscope (OM) were used to investigate morphology and geometry of the product. The effects of dispersion rate, weight ratio of core to shell and emulsifier concentration were carefully analyzed. It was found that poly(melamine-formaldehyde) (PMF) microcapsules containing styrene were successfully synthesized through the proposed technical route, and their mean diameters fall in the range of 20~71 µm. The rough surface of the microcapsules is composed of agglomerated PMF nanoparticles. Both core content and size of the microcapsule can be adjusted by selecting different processing parameters. The highest loading of styrene in the capsules is about 60% and the emulsifier with lower molecular weight used to result in higher core content. In terms of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), thermal behavior and storage stability of the capsules were studied. The results indicated that the microcapsules can be handled up to 72 oC.

The Preparation and Research of Microcapsules in Self-Healing Coatings

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.

scholarly journals New method of paper hydrophobization based on starch-cellulose-siloxane interactions

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 4124-4142
Author(s):  
Tomasz Ganicz ◽  
Konrad Olejnik ◽  
Krystyna Rózga-Wijas ◽  
Jan Kurjata
Keyword(s):  
New Method ◽  
Hydrophobic Properties ◽  
Sem Images ◽  
Water Contact ◽  
Water Emulsion ◽  
Coating Agent ◽  
Angle Measurements ◽  
Coated Materials ◽  
Tear Index ◽  
Contact Angle Measurements

A new method of paper hydrophobization was evaluated based on a coating agent containing a water emulsion of triethoxymethylsilane with standard starch solutions. The effects of different concentrations on the hydrophobic properties of the resulting silicone-coated materials were investigated using a penetration dynamics analyzer (PDA) and water contact angle measurements. This study also examined the effects of the applied coatings on the paper’s tensile strength, tear index, roughness, air permeance, and ISO brightness. Preliminary studies were conducted on the molecular interaction mechanisms between the silicone agent and starch modifiers, based on solid state nuclear magnetic resonance (NMR) and scanning electron microscope (SEM) images.

scholarly journals A Novel Self-Healing Epoxy System with Microencapsulated Epoxy and Imidazole Curing Agent

2007 ◽  
Vol 16 (5) ◽  
pp. 096369350701600 ◽  
Author(s):  
Min Zhi Rong ◽  
Ming Qiu Zhang ◽  
Wei Zhang
Keyword(s):  
Urea Formaldehyde ◽  
Weight Ratio ◽  
The Self ◽  
Wall Material ◽  
Self Healing ◽  
Epoxy System ◽  
Water Emulsion ◽  
Fracture Toughness Measurement ◽  
Healing Agent ◽  
Oil In Water Emulsion

This work reported a novel epoxy system that can perform a self-repairing operation against cracks at elevated temperature. For this purpose, a two-component healing agent consisting of microencapsulated epoxy and imidazole was pre-embedded into epoxy matrix. The microencapsulated epoxy was self-synthesized in advance using poly(urea-formaldehyde) as the wall material through a two-step polymerization approach in an oil-in-water emulsion. The performance of the self-healing epoxy composite was evaluated by fracture toughness measurement. It was found that the self-healing epoxy containing 20wt.% healing agent received a healing efficiency of 106% at the optimum capsulated imidazole-to-epoxy weight ratio of 0.2.

Optimized synthesis of isocyanate microcapsules for self-healing application in epoxy composites

2020 ◽  
Vol 32 (6) ◽  
pp. 669-680 ◽  
Author(s):  
Yong Sun ◽  
Shugang Wang ◽  
Xiaosu Dong ◽  
Yuntao Liang ◽  
Wei Lu ◽  
...  
Keyword(s):  
Mechanical Test ◽  
Optical Microscope ◽  
Epoxy Composites ◽  
Self Healing ◽  
Accelerated Corrosion ◽  
Water Emulsion ◽  
Core Content ◽  
Accelerated Corrosion Test ◽  
Oil In Water Emulsion ◽  
Processing Properties

Microcapsules containing isophorone diisocyanate were fabricated in oil-in-water emulsion. The emulsification effect of different emulsifiers during the capsule synthesis was systematically investigated by optical microscope. Three kinds of shell materials were discussed to obtain the high core content, smooth-surfaced, and robust capsule by scanning electronic microscope and Fourier transform infrared spectroscopy. Self-healing performance of corresponding self-healing epoxy composites was fully evaluated by accelerated corrosion test and mechanical test. The results demonstrated that high core content and smooth-surfaced capsules with dense composite shell could be synthesized in polyvinyl alcohol emulsion, and the core content of the optimized capsules was determined as 71.3–84.6 wt% at the capsule size from 35 µm to 154 µm. In addition, the optimized capsules had good processing properties and the corresponding self-healing epoxy composites exhibited excellent core release and self-healing performance.

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