scholarly journals Synthesis of Urea Formaldehyde microcapsules containing linseed oil for self-healing coating

2016 ◽  
Vol 19 (4) ◽  
pp. 50-57
Author(s):  
Ha Thi Thai La ◽  
Tinh Dinh Cong Vo
Keyword(s):  
Emulsion Polymerization ◽  
Sodium Dodecyl Sulphate ◽  
Linseed Oil ◽  
Urea Formaldehyde ◽  
Sodium Dodecyl ◽  
Agitation Rate ◽  
Self Healing ◽  
The Core ◽  
Average Size

Microcapsules had Urea Formaldehyde (UF) shell and linseed oil core were investigated manufacture. Synthesis UF shell of Microcapsules was experimented by emulsion polymerization and pH was only adjusted once by mixer of Resorcinol / Amoni Clorua. Content of Urea and emulsifiler Sodium Dodecyl Sulphate, pH, agitation rate were investigated. This research shows that the linseed oil (core) is disintegrated at 1,500 rpm in pH = 5.5 with 1.2% (w/w) Sodium Dodecyl Sulphate. In addition, the combination of Urea used in order to create the shell about 40% (w/w) linseed oil and Formaldehyde are suitable. The microcapsules products have the average size less 100 μm. Besides that, the content of the linseed oil in the core is about 87% (w/w)take the advantage to use in self-healing coating.

Preparation and characterisation of melamine-urea-formaldehyde microcapsules containing linseed oil in the presence of polyvinylpyrrolidone as emulsifier

2017 ◽  
Vol 46 (4) ◽  
pp. 318-326 ◽  
Author(s):  
Amir Khalaj Asadi ◽  
Morteza Ebrahimi ◽  
Mohsen Mohseni
Keyword(s):  
Particle Size ◽  
Maleic Anhydride ◽  
Linseed Oil ◽  
Urea Formaldehyde ◽  
Ph Control ◽  
Synthesis Process ◽  
Gravimetric Analysis ◽  
Agitation Rate ◽  
Self Healing ◽  
Content Type

Purpose The purpose of this work was to express a facile method to fabricate microcapsules containing linseed oil with melamine-urea-formaldehyde (MUF) shell in the presence of polyvinylpyrrolidone (PVP) as an emulsifier. These microcapsules may be used in self-healing coating formulations. Design/methodology/approach In this work, different types of PVP (i.e., PVP with different molecular weights or K values) were used as emulsifiers and colloid protectors to encapsulate linseed oil in an MUF shell. Moreover, the effect of agitation rate on the morphology of the microcapsules was investigated. Microcapsule morphology and particle size distribution were evaluated using optical microscopy and scanning electron microscopy. Thermal studies were performed using a thermo-gravimetric analysis technique and chemical structure of materials was characterized by using Fourier transform infrared analysis. Findings In this work, microcapsules with a regular spherical shape and a shell thickness of about 330 nm were fabricated. The results revealed that the use of PVP in the fabrication of MUF could facilitate the synthesis process by eliminating the necessity of pH control during the reaction. In fact, the pH of the reaction media must be precisely controlled in conventional processes. The yield of microencapsulation was found to be 86.5 per cent when a high molecular weight of PVP (PVP K-90) was used. It was also found that the surface morphology of microcapsules became smoother when PVP K-90 was used. The results showed that the surface roughness and the average particle size decreased with an increase in stirring intensity. Mean diameter of the prepared microcapsules ranged from 34 to 346 μmin for various synthesis conditions. Research limitations/implications This work is limited to the encapsulation of a hydrophobic liquid (such as linseed oil) by an in situ polymerisation of amino resins. Practical implications The presented results can be used by researchers (in academia and industry) who are working in the field of fabrication microcapsules, in various applications such as pharmaceuticals, electrophoretic displays, textiles, carbonless copy papers, cosmetics, printing and self-healing materials. Social implications PVP is considered as an environmentally friendly emulsifier. Therefore, this process is less harmful to the environment. In addition, the prepared microcapsules may be used in self-healing coatings, which helps in reducing maintenance costs for buildings and steel structures. Originality/value Ethylene maleic anhydride and styrene maleic anhydride are usually used as emulsifiers in conventional methods for the preparation of amino resin microcapsules. These methods require an intensive and precise pH control to obtain favourable microcapsules, while in the present research, a facile method was used to fabricate MUF microcapsules containing linseed oil without needing any pH control during the reaction.

scholarly journals Self-Healing Performance of Multifunctional Polymeric Smart Coatings

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1519 ◽  
Author(s):  
Sehrish Habib ◽  
Adnan Khan ◽  
Muddasir Nawaz ◽  
Mostafa Sliem ◽  
Rana Shakoor ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Linseed Oil ◽  
Steel Substrate ◽  
Urea Formaldehyde ◽  
Nanocomposite Coatings ◽  
Self Healing ◽  
Ph Change ◽  
Polymeric Nanocomposite ◽  
Smart Coatings ◽  
Healing Agent

Multifunctional nanocomposite coatings were synthesized by reinforcing a polymeric matrix with halloysite nanotubes (HNTs) loaded with corrosion inhibitor (NaNO3) and urea formaldehyde microcapsules (UFMCs) encapsulated with a self-healing agent (linseed oil (LO)). The developed polymeric nanocomposite coatings were applied on the polished mild steel substrate using the doctor’s blade technique. The structural (FTIR, XPS) and thermogravimetric (TGA) analyses reveal the loading of HNTs with NaNO3 and encapsulation of UFMCs with linseed oil. It was observed that self-release of the inhibitor from HNTs in response to pH change was a time dependent process. Nanocomposite coatings demonstrate decent self-healing effects in response to the external controlled mechanical damage. Electrochemical impedance spectroscopic analysis (EIS) indicates promising anticorrosive performance of novel nanocomposite coatings. Observed corrosion resistance of the developed smart coatings may be attributed to the efficient release of inhibitor and self-healing agent in response to the external stimuli. Polymeric nanocomposite coatings modified with multifunctional species may offer suitable corrosion protection of steel in the oil and gas industry.

scholarly journals Development and Performance Evaluation of Corrosion Resistance Self-Healing Coating

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Akshya Kumar Guin ◽  
Suryakanta Nayak ◽  
Manish Kumar Bhadu ◽  
Veena Singh ◽  
Tapan Kumar Rout
Keyword(s):  
Corrosion Resistance ◽  
Performance Evaluation ◽  
Urea Formaldehyde ◽  
Sol Gel ◽  
Core Material ◽  
Self Healing ◽  
Nacl Solution ◽  
The Core ◽  
Steel Protection ◽  
And Performance

Polymer based nanocapsule was developed using core-cell approach, where the core material was methyl diphenyl diisocyanate and the cell material was urea-formaldehyde. The synthesized capsules of 100 to 800 nm size were incorporated into sol-gel matrix to prepare a final coating for steel protection. This coating was found protecting the steel at the damage or crack locations in 3.5% NaCl solution. SEM micrographs confirmed healing of the coating at the damage or crack points.

Strippable Core-Shell Polymer Emulsion for Decontamination of Radioactive Surface Contamination

2010 ◽  
Author(s):  
Ho-Sang Hwang ◽  
Bum-Kyoung Seo ◽  
Kune-Woo Lee
Keyword(s):  
Emulsion Polymerization ◽  
Shell Structure ◽  
Sodium Dodecyl ◽  
Ethyl Acrylate ◽  
Surface Contamination ◽  
Core Shell ◽  
Composite Polymer ◽  
Polymer Emulsion ◽  
The Core ◽  
Core Shell Structure

In this study, the core-shell composite polymer for decontamination from the surface contamination was synthesized by the method of emulsion polymerization and blends of polymers. The strippable polymer emulsion is composed of the poly(styrene-ethyl acrylate) [poly(St-EA)] composite polymer, poly(vinyl alcohol) (PVA) and polyvinylpyrrolidone (PVP). The morphology of the poly(St-EA) composite emulsion particle was core-shell structure, with polystyrene (PS) as the core and poly(ethyl acrylate) (PEA) as the shell. Core-shell polymers of styrene (St)/ethyl acrylate (EA) pair were prepared by sequential emulsion polymerization in the presence of sodium dodecyl sulfate (SDS) as an emulsifier using ammonium persulfate (APS) as an initiator. Related tests and analysis confirmed the success in synthesis of composite polymer. The products are characterized by FT-IR spectroscopy, TGA that were used, respectively, to show the structure, the thermal stability of the prepared polymer. Two-phase particles with a core-shell structure were obtained in experiments where the estimated glass transition temperature and the morphologies of emulsion particles. Decontamination factors of the strippable polymeric emulsion were evaluated with the polymer blend contents.

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 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.

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