The Experts below are selected from a list of 5922 Experts worldwide ranked by ideXlab platform
Ramin Farnood - One of the best experts on this subject based on the ideXlab platform.
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amino silane surface modification of urea formaldehyde Microcapsules containing linseed oil for improved epoxy matrix compatibility part i optimizing silane treatment conditions
2019Co-Authors: S M Mirabedini, M Esfandeh, Ramin Farnood, P RajabiAbstract:Abstract In Microcapsule-filled self-healing coatings, a good Microcapsule/matrix interface improves repairing performance by directing the crack through the Microcapsule and releasing the core material. In this study, the surface of the synthesized linseed oil filled polyurea-formaldehyde (PUF) based Microcapsules was treated with 3-aminopropyltrimethoxy silane (APS, via a two-step sol-gel route), in order to improve its interface with an epoxy coating. The treated Microcapsules were then characterized using various characterization techniques. The effect of silane treatment on the Microcapsule/matrix interface and tensile properties of the coating was evaluated. FTIR spectroscopy showed both physical and chemical interactions between APS and PUF Microcapsules. SEM micrographs revealed an almost spherical morphology for both treated and un-treated Microcapsules. TGA results showed that the maximum silane grafting occurs at pH 7.5. It was found that the addition of APS-treated Microcapsules had a positive effect on the tensile properties of the coating due to improving Microcapsule’s shell and polymer matrix compatibility. This was related to the reaction of hydroxyl groups on PUF Microcapsules and silanol groups of the silane and the subsequent reaction of amine group of the silane with the epoxy group of the coating.
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evaluation of corrosion performance of a self healing epoxy based coating containing linseed oil filled Microcapsules via electrochemical impedance spectroscopy
2017Co-Authors: M Behzadnasab, S M Mirabedini, M Esfandeh, Ramin FarnoodAbstract:Abstract Linseed oil filled urea-formaldehyde Microcapsules with various sizes were prepared via in-situ polymerization. To understand the healing performance of linseed oil as a healing agent and the progression of corrosion processes beneath the healed area, long term corrosion performance of scratched epoxy-based coating samples containing Microcapsules was evaluated using Electrochemical Impedance Spectroscopy (EIS) as well as salt spray testing over a period of 6-days. EIS results were fitted to various equivalent circuit models and a modified model for the justification of the observed corrosion behavior was proposed. It was found that the addition of Microcapsules enhances the corrosion resistance of the scratched samples, the extent of which depends on the Microcapsule size and loading. At a given loading, corrosion resistance increased with increasing Microcapsule size, however, the effect of Microcapsule size was more significant than that of loading. Moreover, with increased exposure time to the salt solution, the corrosion behavior of scratched coated samples shifted from uniform corrosion to crevice corrosion. EIS results showed that although linseed-oil can significantly improve the corrosion performance of the damaged coating in short term however it rapidly decreases with time and hence this should be taken into account in designing of Microcapsule’s core composition.
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preparation and characterization of linseed oil filled urea formaldehyde Microcapsules and their effect on mechanical properties of an epoxy based coating
2014Co-Authors: M Behzadnasab, S M Mirabedini, M Esfandeh, M J Zohuriaanmehr, Ramin FarnoodAbstract:Abstract In this study, urea–formaldehyde based Microcapsules containing linseed oil were prepared via in situ polymerization method. Microcapsules with a regular spherical shape, 10–300 μm diameter and an oil content of 63–77 wt% were synthesized in various core:shell ratios and different mixing speeds. The effect of core:shell ratio and mixing speed on the size and morphology of the Microcapsule were studied using optical microscopy, SEM and particle size analysis. Epoxy-based coatings containing various amounts of Microcapsules were prepared and the effect of Microcapsule size and loading on the mechanical properties and healing performance were evaluated by measuring the tensile properties and corrosion performance of the coatings. The amount of the oil released in the scratched coating was determined both practically and theoretically and the results were compared. The results showed that the addition of Microcapsules reduces the tensile properties of the coating, the extent of which depends on the Microcapsule size and loading wt%. For instance, sample containing 3 wt% of the Microcapsules with an average particle size of 53 μm showed 8.6% reduction in tensile modulus. Optical microscopy of the scratched sample revealed that with increasing Microcapsules’ size and loading, the crack was filled more effectively and this led to an improved corrosion performance. Finally, the optimum combination of self-healing and mechanical properties was found to be for the coating containing 5 wt% of Microcapsules, with an average particle size of 53 μm.
Daijie Chen - One of the best experts on this subject based on the ideXlab platform.
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extending viability of bifidobacterium longum in chitosan coated alginate Microcapsules using emulsification and internal gelation encapsulation technology
2019Co-Authors: Rui Ji, Junliang Zhang, Jiahui Wu, Lei Shao, Xudong Zhang, Tao Wang, Daijie ChenAbstract:Bifidobacteria are considered one of the most important intestinal probiotics because of their significant health impact. However, due to gastrointestinal fluid sensitivity, a number of supplementary Bifidobacteria are unable to survive passage through the gastrointestinal tract, severely limiting their ability to confer health benefits to the host. Emulsification and internal gelation are an encapsulation technique with great potential for probiotic protection during storage and the gastrointestinal transit process. This study prepared Microcapsules using an emulsification and internal gelation encapsulation method with sodium alginate, chitosan, and Bifidobacterium longum as wall material, coating material, experimental strain, respectively. Optical, scanning electron, and focal microscopes were used to observe the Microcapsule surface morphology and internal viable cell distribution, and a laser particle size analyser and zeta potentiometer were used to evaluate the chitosan coating characteristics. In addition, Microcapsule probiotic viability after storage, heat treatment, and simulated gastrointestinal fluid treatment were examined. Alginate Microcapsules and chitosan-coated alginate Microcapsules both had balling properties and uniform bacterial distribution. The latter kept its balling properties after freeze-drying, verified by SEM, and had a clear external coating, observed by optical microscope. The particle size of chitosan-coated alginate Microcapsules was slightly larger than the uncoated Microcapsules. The zeta potential of alginate and chitosan-coated alginate Microcapsules was negative and positive, respectively. Heat, acid and bile salt tolerance, and stability tests revealed that the decrease of viable cells in the chitosan-coated alginate Microcapsule group was significantly lower than in uncoated Microcapsules. These experimental results indicate that the chitosan-coated alginate Microcapsules protect B. longum from gastro-intestinal fluid and high temperature conditions.
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extending viability of bifidobacterium longum in chitosan coated alginate Microcapsules using emulsification and internal gelation encapsulation technology
2019Co-Authors: Junliang Zhang, Daijie Chen, Lei Shao, Xudong Zhang, Tao Wang, Jing WangAbstract:Bifidobacteria are considered one of the most important intestinal probiotics because of their significant health impact. However, this ability is usually limited by gastrointestinal fluid and temperature sensitivity. Emulsification and internal gelation is an encapsulation technique with great potential for probiotic protection during storage and the gastrointestinal transit process. This study prepared Microcapsules using an emulsification and internal gelation encapsulation method with sodium alginate, chitosan, and Bifidobacterium longum as wall material, coating material, and experimental strain, respectively. Optical, scanning electron, and focal microscopes were used to observe the Microcapsule surface morphology and internal viable cell distribution, and a laser particle size analyzer and zeta potentiometer were used to evaluate the chitosan-coating characteristics. In addition, Microcapsule probiotic viability after storage, heat treatment, and simulated gastrointestinal fluid treatment were examined. Alginate Microcapsules and chitosan-coated alginate Microcapsules both had balling properties and uniform bacterial distribution. The latter kept its balling properties after freeze-drying, verified by scanning electronic microscopy (SEM), and had a clear external coating, observed by an optical microscope. The particle size of chitosan-coated alginate Microcapsules was slightly larger than the uncoated Microcapsules. The zeta potential of alginate and chitosan-coated alginate Microcapsules was negative and positive, respectively. Heat, acid and bile salt tolerance, and stability tests revealed that the decrease of viable cells in the chitosan-coated alginate Microcapsule group was significantly lower than that in uncoated Microcapsules. These experimental results indicate that the chitosan-coated alginate Microcapsules protect B. longum from gastrointestinal fluid and high-temperature conditions.
S M Mirabedini - One of the best experts on this subject based on the ideXlab platform.
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amino silane surface modification of urea formaldehyde Microcapsules containing linseed oil for improved epoxy matrix compatibility part i optimizing silane treatment conditions
2019Co-Authors: S M Mirabedini, M Esfandeh, Ramin Farnood, P RajabiAbstract:Abstract In Microcapsule-filled self-healing coatings, a good Microcapsule/matrix interface improves repairing performance by directing the crack through the Microcapsule and releasing the core material. In this study, the surface of the synthesized linseed oil filled polyurea-formaldehyde (PUF) based Microcapsules was treated with 3-aminopropyltrimethoxy silane (APS, via a two-step sol-gel route), in order to improve its interface with an epoxy coating. The treated Microcapsules were then characterized using various characterization techniques. The effect of silane treatment on the Microcapsule/matrix interface and tensile properties of the coating was evaluated. FTIR spectroscopy showed both physical and chemical interactions between APS and PUF Microcapsules. SEM micrographs revealed an almost spherical morphology for both treated and un-treated Microcapsules. TGA results showed that the maximum silane grafting occurs at pH 7.5. It was found that the addition of APS-treated Microcapsules had a positive effect on the tensile properties of the coating due to improving Microcapsule’s shell and polymer matrix compatibility. This was related to the reaction of hydroxyl groups on PUF Microcapsules and silanol groups of the silane and the subsequent reaction of amine group of the silane with the epoxy group of the coating.
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evaluation of corrosion performance of a self healing epoxy based coating containing linseed oil filled Microcapsules via electrochemical impedance spectroscopy
2017Co-Authors: M Behzadnasab, S M Mirabedini, M Esfandeh, Ramin FarnoodAbstract:Abstract Linseed oil filled urea-formaldehyde Microcapsules with various sizes were prepared via in-situ polymerization. To understand the healing performance of linseed oil as a healing agent and the progression of corrosion processes beneath the healed area, long term corrosion performance of scratched epoxy-based coating samples containing Microcapsules was evaluated using Electrochemical Impedance Spectroscopy (EIS) as well as salt spray testing over a period of 6-days. EIS results were fitted to various equivalent circuit models and a modified model for the justification of the observed corrosion behavior was proposed. It was found that the addition of Microcapsules enhances the corrosion resistance of the scratched samples, the extent of which depends on the Microcapsule size and loading. At a given loading, corrosion resistance increased with increasing Microcapsule size, however, the effect of Microcapsule size was more significant than that of loading. Moreover, with increased exposure time to the salt solution, the corrosion behavior of scratched coated samples shifted from uniform corrosion to crevice corrosion. EIS results showed that although linseed-oil can significantly improve the corrosion performance of the damaged coating in short term however it rapidly decreases with time and hence this should be taken into account in designing of Microcapsule’s core composition.
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preparation and characterization of linseed oil filled urea formaldehyde Microcapsules and their effect on mechanical properties of an epoxy based coating
2014Co-Authors: M Behzadnasab, S M Mirabedini, M Esfandeh, M J Zohuriaanmehr, Ramin FarnoodAbstract:Abstract In this study, urea–formaldehyde based Microcapsules containing linseed oil were prepared via in situ polymerization method. Microcapsules with a regular spherical shape, 10–300 μm diameter and an oil content of 63–77 wt% were synthesized in various core:shell ratios and different mixing speeds. The effect of core:shell ratio and mixing speed on the size and morphology of the Microcapsule were studied using optical microscopy, SEM and particle size analysis. Epoxy-based coatings containing various amounts of Microcapsules were prepared and the effect of Microcapsule size and loading on the mechanical properties and healing performance were evaluated by measuring the tensile properties and corrosion performance of the coatings. The amount of the oil released in the scratched coating was determined both practically and theoretically and the results were compared. The results showed that the addition of Microcapsules reduces the tensile properties of the coating, the extent of which depends on the Microcapsule size and loading wt%. For instance, sample containing 3 wt% of the Microcapsules with an average particle size of 53 μm showed 8.6% reduction in tensile modulus. Optical microscopy of the scratched sample revealed that with increasing Microcapsules’ size and loading, the crack was filled more effectively and this led to an improved corrosion performance. Finally, the optimum combination of self-healing and mechanical properties was found to be for the coating containing 5 wt% of Microcapsules, with an average particle size of 53 μm.
M Esfandeh - One of the best experts on this subject based on the ideXlab platform.
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amino silane surface modification of urea formaldehyde Microcapsules containing linseed oil for improved epoxy matrix compatibility part i optimizing silane treatment conditions
2019Co-Authors: S M Mirabedini, M Esfandeh, Ramin Farnood, P RajabiAbstract:Abstract In Microcapsule-filled self-healing coatings, a good Microcapsule/matrix interface improves repairing performance by directing the crack through the Microcapsule and releasing the core material. In this study, the surface of the synthesized linseed oil filled polyurea-formaldehyde (PUF) based Microcapsules was treated with 3-aminopropyltrimethoxy silane (APS, via a two-step sol-gel route), in order to improve its interface with an epoxy coating. The treated Microcapsules were then characterized using various characterization techniques. The effect of silane treatment on the Microcapsule/matrix interface and tensile properties of the coating was evaluated. FTIR spectroscopy showed both physical and chemical interactions between APS and PUF Microcapsules. SEM micrographs revealed an almost spherical morphology for both treated and un-treated Microcapsules. TGA results showed that the maximum silane grafting occurs at pH 7.5. It was found that the addition of APS-treated Microcapsules had a positive effect on the tensile properties of the coating due to improving Microcapsule’s shell and polymer matrix compatibility. This was related to the reaction of hydroxyl groups on PUF Microcapsules and silanol groups of the silane and the subsequent reaction of amine group of the silane with the epoxy group of the coating.
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evaluation of corrosion performance of a self healing epoxy based coating containing linseed oil filled Microcapsules via electrochemical impedance spectroscopy
2017Co-Authors: M Behzadnasab, S M Mirabedini, M Esfandeh, Ramin FarnoodAbstract:Abstract Linseed oil filled urea-formaldehyde Microcapsules with various sizes were prepared via in-situ polymerization. To understand the healing performance of linseed oil as a healing agent and the progression of corrosion processes beneath the healed area, long term corrosion performance of scratched epoxy-based coating samples containing Microcapsules was evaluated using Electrochemical Impedance Spectroscopy (EIS) as well as salt spray testing over a period of 6-days. EIS results were fitted to various equivalent circuit models and a modified model for the justification of the observed corrosion behavior was proposed. It was found that the addition of Microcapsules enhances the corrosion resistance of the scratched samples, the extent of which depends on the Microcapsule size and loading. At a given loading, corrosion resistance increased with increasing Microcapsule size, however, the effect of Microcapsule size was more significant than that of loading. Moreover, with increased exposure time to the salt solution, the corrosion behavior of scratched coated samples shifted from uniform corrosion to crevice corrosion. EIS results showed that although linseed-oil can significantly improve the corrosion performance of the damaged coating in short term however it rapidly decreases with time and hence this should be taken into account in designing of Microcapsule’s core composition.
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preparation and characterization of linseed oil filled urea formaldehyde Microcapsules and their effect on mechanical properties of an epoxy based coating
2014Co-Authors: M Behzadnasab, S M Mirabedini, M Esfandeh, M J Zohuriaanmehr, Ramin FarnoodAbstract:Abstract In this study, urea–formaldehyde based Microcapsules containing linseed oil were prepared via in situ polymerization method. Microcapsules with a regular spherical shape, 10–300 μm diameter and an oil content of 63–77 wt% were synthesized in various core:shell ratios and different mixing speeds. The effect of core:shell ratio and mixing speed on the size and morphology of the Microcapsule were studied using optical microscopy, SEM and particle size analysis. Epoxy-based coatings containing various amounts of Microcapsules were prepared and the effect of Microcapsule size and loading on the mechanical properties and healing performance were evaluated by measuring the tensile properties and corrosion performance of the coatings. The amount of the oil released in the scratched coating was determined both practically and theoretically and the results were compared. The results showed that the addition of Microcapsules reduces the tensile properties of the coating, the extent of which depends on the Microcapsule size and loading wt%. For instance, sample containing 3 wt% of the Microcapsules with an average particle size of 53 μm showed 8.6% reduction in tensile modulus. Optical microscopy of the scratched sample revealed that with increasing Microcapsules’ size and loading, the crack was filled more effectively and this led to an improved corrosion performance. Finally, the optimum combination of self-healing and mechanical properties was found to be for the coating containing 5 wt% of Microcapsules, with an average particle size of 53 μm.
Junliang Zhang - One of the best experts on this subject based on the ideXlab platform.
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extending viability of bifidobacterium longum in chitosan coated alginate Microcapsules using emulsification and internal gelation encapsulation technology
2019Co-Authors: Rui Ji, Junliang Zhang, Jiahui Wu, Lei Shao, Xudong Zhang, Tao Wang, Daijie ChenAbstract:Bifidobacteria are considered one of the most important intestinal probiotics because of their significant health impact. However, due to gastrointestinal fluid sensitivity, a number of supplementary Bifidobacteria are unable to survive passage through the gastrointestinal tract, severely limiting their ability to confer health benefits to the host. Emulsification and internal gelation are an encapsulation technique with great potential for probiotic protection during storage and the gastrointestinal transit process. This study prepared Microcapsules using an emulsification and internal gelation encapsulation method with sodium alginate, chitosan, and Bifidobacterium longum as wall material, coating material, experimental strain, respectively. Optical, scanning electron, and focal microscopes were used to observe the Microcapsule surface morphology and internal viable cell distribution, and a laser particle size analyser and zeta potentiometer were used to evaluate the chitosan coating characteristics. In addition, Microcapsule probiotic viability after storage, heat treatment, and simulated gastrointestinal fluid treatment were examined. Alginate Microcapsules and chitosan-coated alginate Microcapsules both had balling properties and uniform bacterial distribution. The latter kept its balling properties after freeze-drying, verified by SEM, and had a clear external coating, observed by optical microscope. The particle size of chitosan-coated alginate Microcapsules was slightly larger than the uncoated Microcapsules. The zeta potential of alginate and chitosan-coated alginate Microcapsules was negative and positive, respectively. Heat, acid and bile salt tolerance, and stability tests revealed that the decrease of viable cells in the chitosan-coated alginate Microcapsule group was significantly lower than in uncoated Microcapsules. These experimental results indicate that the chitosan-coated alginate Microcapsules protect B. longum from gastro-intestinal fluid and high temperature conditions.
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extending viability of bifidobacterium longum in chitosan coated alginate Microcapsules using emulsification and internal gelation encapsulation technology
2019Co-Authors: Junliang Zhang, Daijie Chen, Lei Shao, Xudong Zhang, Tao Wang, Jing WangAbstract:Bifidobacteria are considered one of the most important intestinal probiotics because of their significant health impact. However, this ability is usually limited by gastrointestinal fluid and temperature sensitivity. Emulsification and internal gelation is an encapsulation technique with great potential for probiotic protection during storage and the gastrointestinal transit process. This study prepared Microcapsules using an emulsification and internal gelation encapsulation method with sodium alginate, chitosan, and Bifidobacterium longum as wall material, coating material, and experimental strain, respectively. Optical, scanning electron, and focal microscopes were used to observe the Microcapsule surface morphology and internal viable cell distribution, and a laser particle size analyzer and zeta potentiometer were used to evaluate the chitosan-coating characteristics. In addition, Microcapsule probiotic viability after storage, heat treatment, and simulated gastrointestinal fluid treatment were examined. Alginate Microcapsules and chitosan-coated alginate Microcapsules both had balling properties and uniform bacterial distribution. The latter kept its balling properties after freeze-drying, verified by scanning electronic microscopy (SEM), and had a clear external coating, observed by an optical microscope. The particle size of chitosan-coated alginate Microcapsules was slightly larger than the uncoated Microcapsules. The zeta potential of alginate and chitosan-coated alginate Microcapsules was negative and positive, respectively. Heat, acid and bile salt tolerance, and stability tests revealed that the decrease of viable cells in the chitosan-coated alginate Microcapsule group was significantly lower than that in uncoated Microcapsules. These experimental results indicate that the chitosan-coated alginate Microcapsules protect B. longum from gastrointestinal fluid and high-temperature conditions.