scholarly journals Self-Healing Performance of Smart Polymeric Coatings Modified with Tung Oil and Linalyl Acetate

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1609
Author(s):  
Norhan Ashraf Ismail ◽  
Adnan Khan ◽  
Eman Fayyad ◽  
Ramazan Kahraman ◽  
Aboubakr M. Abdullah ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
In Situ Polymerization ◽  
Urea Formaldehyde ◽  
Average Particle Size ◽  
Average Particle ◽  
Self Healing ◽  
Polymeric Coatings ◽  
Linalyl Acetate ◽  
Tung Oil ◽  
Smart Coatings

This work focuses on the synthesis and characterization of polymeric smart self-healing coatings. A comparison of structural, thermal, and self-healing properties of two different polymeric coatings comprising distinct self-healing agents (tung oil and linalyl acetate) is studied to elucidate the role of self-healing agents in corrosion protection. Towards this direction, urea-formaldehyde microcapsules (UFMCs) loaded with tung oil (TMMCs) and linalyl acetate (LMMCs) were synthesized using the in-situ polymerization method. The synthesis of both LMMCs and TMMCs under identical experimental conditions (900 rpm, 55 °C) has resulted in a similar average particle size range (63–125 µm). The polymeric smart self-healing coatings were developed by reinforcing a polymeric matrix separately with a fixed amount of LMMCs (3 wt.% and 5 wt.%), and TMMCs (3 wt.% and 5 wt.%) referred to as LMCOATs and TMCOATs, respectively. The development of smart coatings (LMCOATs and TMCOATs) contributes to achieving decent thermal stability up to 450 °C. Electrochemical impedance spectroscopy (EIS) analysis indicates that the corrosion resistance of smart coatings increases with increasing concentration of the microcapsules (TMMCs, LMMCs) in the epoxy matrix reaching ~1 GΩ. As a comparison, LMCOATs containing 5 wt.% LMMCs demonstrate the best stability in the barrier properties than other developed coatings and can be considered for many potential applications.

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 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.

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.

The Effects of Synthesis Conditions on PUF Microcapsule Morphology

2012 ◽  
Vol 217-219 ◽  
pp. 661-665
Author(s):  
Ning Ning Hu ◽  
Hao Han Huang ◽  
Hong Zhi Cui
Keyword(s):  
Particle Size ◽  
In Situ Polymerization ◽  
Average Particle Size ◽  
Wall Material ◽  
Average Particle ◽  
Self Healing ◽  
Test Results ◽  
Synthesis Conditions ◽  
Wide Range

In this paper, self-healing PUF microcapsules were prepared by in situ polymerization. The test results show that: 1) the ratio of core/wall material can had a significant effect on the average particle size of microcapsules. The ratio happens to be 1.0 to 1.0, best coating, relatively dense surface can be achieved. When the ratio reaches 1.4 to 1.0, the microcapsules have worst coating, particle size, distribution of wide range, and comparatively rough surface. When the ratio is 0.8 to 1.0 or 1.2 to 1.0, preferable coating, uniform particle size and its distribution, as well as smooth and dense surface can be obtained. 2) The faster the stirring speed, the smaller the particle size of microcapsule will be. And the size becomes bigger and varied with the stirring speed decreasing.

scholarly journals Cellulose microfibers (CMFs) reinforced smart self-healing polymeric composite coatings for corrosion protection of steel

2020 ◽  
Author(s):  
Muddasir Nawaz ◽  
Sehrish Habib ◽  
Adnan Khan ◽  
Abdul Shakoor ◽  
Ramazan Kahraman
Keyword(s):  
Corrosion Resistance ◽  
Immersion Time ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Polymeric Composite ◽  
Protective Film ◽  
Self Healing ◽  
Ph Change ◽  
Smart Coatings ◽  
Cellulose Microfibers

The use of organic coating for the metals has been widely being used to protect the surface against corrosion. Polymeric coating incorporated with Nanocontainers loaded with inhibitor and self-healing provides better corrosion resistance. Cellulose microfibers (CMFs) used as smart carriers were synthesized and loaded with dodecylamine (DOC)-inhibitor and polyethyleneimine (PEI)-both inhibitor and self-healing agents. Smart polymeric coatings were developed by mixing CMF/DOC and CMFs/PEI into the epoxy matrix. Reference coatings (that has only CMFs) were also prepared for a compersion. Scanning electron microscope (SEM), X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR) and thermal gravitational analysis (TGA) were used to confirm the loading of DOC and PEI onto the CMFs. UV-vis analysis indicates that the self-release of inhibitor from CMFs is sensitive to pH of the solution and the immersion time. Recovery of controlled surface damage confirms the decent self-healing ability of the prepared smart coatings is due to the efficient release of inhibitor (DOC) and self-healing agent (PEI) in the damaged area leading to the formation of a protective film. Electrochemical impedance spectroscopy (EIS) results demonstrate that corrosion resistance of the smart coating increases with an increase in immersion time which is due to the progressive release of inhibitors from CMFs in response to the pH change. Therefore, smart coatings demonstrate superior properties as compared to the reference coatings. The study reveals the polymeric composite coatings have potential to inhibit the corrosion of steel for oil and gas industry.

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 Effect of Microcapsules with Different Core–Wall Ratios on Properties of Waterborne Primer Coating for European Linden

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 826 ◽  
Author(s):  
Xiaoxing Yan ◽  
Lin Wang ◽  
Xingyu Qian
Keyword(s):  
In Situ Polymerization ◽  
Urea Formaldehyde ◽  
Impact Resistance ◽  
Acrylic Resin ◽  
Self Healing ◽  
Property A ◽  
Wood Coatings ◽  
Healing Property ◽  
Optical And Mechanical Properties ◽  
The Impact

Waterborne acrylic-resin-filled urea–formaldehyde-based microcapsules with core–wall ratios of 0.42:1, 0.50:1, 0.58:1, 0.67:1, 0.75:1, 0.83:1 and 0.92:1 were prepared via in situ polymerization. Microcapsules were added into the primer to investigate the optical and mechanical properties of the coating on European linden. The results indicated that under the condition of the same core–wall ratio, chroma differences increased gradually with increasing concentration. The coating gloss decreased with increasing concentration. The hardness of 10.0–15.0% microcapsules increased more obviously, with the highest elongations at the break of the coating. At the 0.58:1 core–wall ratio and the 10.0% concentration, the coating adhesion was level 1 and the impact resistance was 10.0 kg cm. Microcapsule concentration did not affect the coating’s liquid resistance. The coating with 10.0% microcapsules added at a 0.58:1 core–wall ratio had a better self-healing property, a good stability and aging resistance. This paper lays a technical basis for the manufacturing and utilization of self-healing waterborne wood coatings.

Microencapsulation of a sunlight-curable silicon-based resin in the presence of polyvinylpyrrolidone

2018 ◽  
Vol 47 (3) ◽  
pp. 272-278 ◽  
Author(s):  
Amir Khalaj Asadi ◽  
Morteza Ebrahimi ◽  
Mohsen Mohseni
Keyword(s):  
Average Particle Size ◽  
Environmentally Friendly ◽  
Average Particle ◽  
Agitation Rate ◽  
Self Healing ◽  
Simple Method ◽  
Water Emulsion ◽  
Content Type ◽  
Catalyst Free

Purpose The purpose of this investigation is to develop a facile method to encapsulate a sunlight-curable silicone-based resin into a melamine–urea–formaldehyde (MUF) shell in the presence of polyvinylpyrrolidone (PVP) as an emulsifier. These microcapsules can be used in self-healing coating formulations. Design/methodology/approach MUF microcapsules containing a sunlight-curable core (methacryloxypropyl-terminated polydimethylsiloxane, MAT-PDMS) have been fabricated by means of in situ polymerisation of an oil-in-water emulsion using PVP as an efficient and environmentally advantageous stabiliser. The effects of agitation rate and PVP concentration on the microencapsulation process have been investigated using optical microscopy (OM) and scanning electron microscopy (SEM). The chemical structure and thermal stability of the microcapsules have been studied using Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The solvent resistance of the microcapsules has been determined as well. Findings It has been revealed that the pH of the reaction mixture remained almost constant during the reaction, which simplified the process. It has also been observed that the microencapsulation yield improved and the microcapsules’ surface morphology became smoother when a high PVP content was used. With an increase in stirring rate from 600 to 1,200 rpm, the surface roughness and the average particle size decreased. The mean diameter of the prepared microcapsules ranged from 32.1 to 327.1 µm depending on the synthesis conditions. It was demonstrated that the microcapsules had a high capacity for MAT-PDMS encapsulation (more than 88 Wt.%). The solvent stability of the microcapsules against different polar, semi-polar and non-polar solvents was also evaluated. Research limitations/implications This research is limited to the encapsulation of a hydrophobic and sunlight curable liquid (such as MAT-PDMS) by means of in situ polymerisation of amino resins. Practical implications The results can be used by researchers working on the fabrication of microcapsules for applications such as drugs, electrophoretic inks, electrophoretic displays, intumescent fire-retardant coatings and self-healing materials. Social implications In self-healing coatings, healing agents which can be cured by UV irradiation or sunlight are envisaged attractive because they are catalyst-free, environmentally friendly and relatively inexpensive. PVP is an environmentally friendly emulsifier. The prepared microcapsules can be used in self-healing coatings to help in reducing maintenance costs for buildings and steel structures. Originality/value The novel aspect of this work is the development of a sunlight-curable silicone-based resin that was encapsulated in a MUF shell in the presence of PVP. A simple method was used to fabricate MUF microcapsules containing MAT-PDMS without the need to control pH during the reaction. Conventional methods for the preparation of amino resin microcapsules require an intensive and precise pH control to obtain favourable microcapsules. MAT-PDMS can be cured by sunlight and is catalyst-free, environmentally friendly and relatively inexpensive.

scholarly journals Double layered Polymeric Coatings for Corrosion Protection of Steel

2021 ◽  
Author(s):  
Amani Hassanein ◽  
Adnan Khan ◽  
R.A. Shakoor ◽  
Ramazan Kahraman
Keyword(s):  
Corrosion Protection ◽  
Linseed Oil ◽  
Steel Substrate ◽  
Urea Formaldehyde ◽  
Bottom Layer ◽  
Halloysite Nanotubes ◽  
Industrial Applications ◽  
Economic Losses ◽  
Self Healing ◽  
Polymeric Coatings

Corrosion is one of the challenging issues faced by many industries, causing substantial economic losses every year due to the degradation of metallic parts, raising many safety concerns. Therefore, it is of utmost relevance to developing strategies that can repair the damaged part of the coatings to protect the base metal and restrict the initiation of corrosion. Towards this direction, the concept of double-layered polymeric coatings (DLPCs) for corrosion protection is introduced as a novel strategy to bring different healing functionalities into coating matrices. The developed DLPCs are composed of a top layer containing 5wt. % of melamine urea-formaldehyde microcapsules (MUFMC) encapsulating boiled linseed oil (self-healing agent), and bottom layer having 3wt. % benzotriazole (corrosion inhibitor) loaded into halloysite nanotubes (HNTs). The DLPCs were developed on mild steel substrate employing a doctor blade technique. The electrochemical analyses indicates that the DLPCs demonstrate improved corrosion resistant properties. This improved performance can be ascribed to the efficient triggering of the individual carriers in the quarantined matrix, resulting in enhanced corrosion efficiency of the DLPCs. The promising characteristics of DLPCs make them suitable for many potential industrial applications.

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.

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