Eunkyoung Shim - Academia.edu (original) (raw)
Papers by Eunkyoung Shim
Journal of Applied Polymer Science, May 14, 2013
Polypropylene (PP) composite filaments containing two different nucleating agents-DMDBS (3 : 2, 4... more Polypropylene (PP) composite filaments containing two different nucleating agents-DMDBS (3 : 2, 4-bis(3,4-dimethyldibenzylidene) sorbitol) and NA11 (sodium 2,2 0-methylene-bis(4,6-di-tertbutylphenyl)-phosphate) were melt spun to modify polymer electrostatic charging characteristics. Sample filaments were charged with a corona instrument and their surface potentials were measured. Initial surface potential as well as potential stability was monitored through an accelerated decay procedure. NA11 was found to be more efficient as an electret additive leading to a 50% increase in charge stability. Filaments with DMDBS exhibited a faster decay. Charging at elevated temperatures resulted in enhanced charge density and stability for both additives. The fiber microstructure was examined by Wide Angle X-ray Diffraction and Differential Scanning Calorimetry. Rather than reducing the crystal sizes, X-Ray diffractograms suggest that the crystal size increases with the addition of nucleating agents, while the degree of crystallinity appears to remain unaltered.
Macromolecular Research, Dec 30, 2015
In this study, surface crystallinity of meltspun polypropylene (PP) filaments was reported. Resul... more In this study, surface crystallinity of meltspun polypropylene (PP) filaments was reported. Results obtained from attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy were confirmed with tapping mode atomic force microscopy (TM-AFM) analysis. ATR-FTIR tests were performed directly on longitudinal surfaces of the filaments, where IR radiation penetrates up to a specific depth. TM-AFM measurements were done on microtomed cross-sections of the filaments, which were scanned carefully to investigate stiffness. Annealing enhanced the surface crystallinity of the filaments in a significant way. Interestingly, samples annealed at 70 and 110 o C for 12 h exhibited similar crystallinity on the uppermost 500 nm surface, whereas for the bulk a continuous increase was observed after XRD studies. 12 h annealing at 70 o C modified the endothermic thermogram, while it did not causes significant effect on overall bulk crystallinity. Differences in the behavior of surface and bulk of the fibrous materials should be considered particularly for surface treatment, i.e. plasma, corona discharge, chemical vapor deposition. Results are also pertinent for water and dye absorbency in polymers.
Water
Anthropogenic activities (e.g., rural urbanization) play major roles in preventing the achievemen... more Anthropogenic activities (e.g., rural urbanization) play major roles in preventing the achievement of sustainable water quality, where eutrophication—the exacerbation of increase in nutrient concentrations combined with warmer temperatures and lower light availability, leading to the dense growth of plant life depleting the amount of available oxygen and killing aquatic life—remains a major challenge for surface water bodies. Filtration mechanisms, with a wide range of applicability, capture common waterborne pathogens as small as 0.1–20.0 μm (bacteria, cysts, spores) and 0.001–0.100 μm (protein, viruses, endotoxins) through the process of microfiltration and ultrafiltration. This study follows the premise of using a designed water flow-through system, with meltblown nonwoven fabrics to measure its performance to capture water contaminant constituents of surface water contamination and eutrophication: total coliforms, nitrate, and orthophosphate. The achieved fabric filtration mecha...
Journal of Applied Polymer Science, 2022
Functional additives, such as mineral and inorganic particles, added significant industrial value... more Functional additives, such as mineral and inorganic particles, added significant industrial value for processing lines such as extrusion and spinning. Within the scope of polymer processing loading mineral additives by compounded mas- terbatch in traditional polyolefin polymers potentially modify those structure bonding by thermal bonding. The large volume of inorganic phase adding raises questions about calcium carbonate as filler in the loading and embossing capacity, quality, and efficient bonding potentiality for relevant products. The process parameters have been recorded around this article on emboss temperature, cal- cium carbonate concentration, web thickness to carry out the hypothesis achiev- able in the spunbond system. Filler adding polypropylene has lower heat capacity, which transfers heat efficiently to achieve optimum bonding effect. Mod- ulated differential scanning calorimeter (MDSC) characterizes heat capacity. Mor- phology of fabric has validated the circumjacent structure changes around the oval pattern. Finally, the conclusion has built a relationship between structure and heat capacity of the inorganic/organic phase, using an equation involving δk ðH,φCaÞ ΔT and the heat capacity correlation with the dosage of CCF.
Smart Textile Coatings and Laminates, 2010
Abstract: Coating and laminating are an essential part of highly functional and technical textile... more Abstract: Coating and laminating are an essential part of highly functional and technical textile development. This chapter discusses general features of coating and laminating process and materials preparations. It also introduces the basic concept of adhesion in the multilayer structure production. Then, the chapter reviews different techniques used to produce coated and laminated fabrics.
Joining Textiles, 2013
Abstract: Coating and laminating are among the best known and oldest techniques to produce compos... more Abstract: Coating and laminating are among the best known and oldest techniques to produce composite or hybrid textiles to achieve functionality and properties that cannot be achieved with single components. General characteristics of coated and laminated fabrics and several of their applications are also discussed.
Smart Textile Coatings and Laminates, 2010
SSRN Electronic Journal, 2021
Polymer, 2018
The work aims at the experimental investigation and theoretical modeling of the physical phenomen... more The work aims at the experimental investigation and theoretical modeling of the physical phenomena responsible for thermal bonding of polymer fibers in nonwovens and their effect on such mechanical properties as the nonwoven stiffness, the yield stress, the stress at failure, toughness, and the entire stress-strain curve. In the experiments two types of
ACS applied materials & interfaces, Jan 9, 2018
Here we describe an electrospun mat of polyvinyl alcohol (PVA) and graphene oxide (GO) as a novel... more Here we describe an electrospun mat of polyvinyl alcohol (PVA) and graphene oxide (GO) as a novel solid-state electrolyte matrix, which offers better performance retention upon drying after infiltrated with aqueous electrolyte. The PVA-GO mat overcomes the major issue of conventional PVA-based electrolytes, which is the ionic conductivity decay upon drying. After exposure to 45±5% relative humidity at 25 ℃ for 1 month, its conductivity decay is limited to 38.4%, whereas that of pure PVA mat is as high as 84.0%. This mainly attributes to the hygroscopic nature of GO and the unique nanofiber structure within the mat. Monolithic supercapacitors have been derived directly on the mat via a well-developed laser-scribing process. The as-prepared supercapacitor offers an areal capacitance of 9.9 mF cmat 40 mV seven after 1-month of aging in ambient conditions, with high device-based volumetric energy density of 0.13 mWh cmand power density of 2.48 W cmrespectively, demonstrating great promi...
ECS Transactions, 2010
The gas diffusion layer (GDL) plays a key role in the overall performance/durability of a polymer... more The gas diffusion layer (GDL) plays a key role in the overall performance/durability of a polymer electrolyte fuel cell (PEFC). Of profound importance, especially in the context of water management and flooding phenomena, is the influence of the underlying pore morphology and wetting characteristics Of the GDL microstructure. In this article, we present the digital volumetric imaging (DVI) technique in order to generate the 3-D carbon paper GD L microstructure. The internal pore structure and the local microstructural variations in terms of fiber alignment and fiberlbinder distributions are investigated using the several 3-D thin sections ofthe sample obtained from DVI.
Macromolecular Research, 2010
Nylon-6 (PA6) nanofiber webs incorporated with boehmite nanoparticles as an electrostatic chargin... more Nylon-6 (PA6) nanofiber webs incorporated with boehmite nanoparticles as an electrostatic charging agent were electrospun and their fiber morphology was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM showed that the median fiber diameter of the PA6 nanofibers was 73 nm and boehmite nanoparticles had little effect on the fiber diameter. The filtration performance of the nanofiber web was measured using 0.3 micron DOP aerosols at a 5.3 cm/s face velocity. Processed and corona charged PA6 nanofiber web showed significant improvement in the submicron aerosol capture efficiency without a change in the air flow resistance compared to the discharged nanofiber web. These results suggest that the electrospinning process imparted electrostatic charge efficiently on the PA6 nanofiber web, and the electrostatic surface potential of a nanofiber web is increased with the incorporation of boehmite nanoparticles.
Journal of Applied Polymer Science, 2011
ABSTRACT
Advanced materials (Deerfield Beach, Fla.), Jan 18, 2015
A simple process for batch or continuous formation of polymer nanofibers and other nanomaterials ... more A simple process for batch or continuous formation of polymer nanofibers and other nanomaterials in the bulk of a sheared fluid medium is introduced. The process could be of high value to commercial nanotechnology as it can be easily scaled up to the fabrication of staple nanofibers at rates that could exceed tens of kilograms per hour.
Textile Research Journal
Spinning technology using melt extrusion and spin-draw processes transforms polymeric materials i... more Spinning technology using melt extrusion and spin-draw processes transforms polymeric materials into highly oriented, crystallized polymeric fibers. Thermoplastic isotactic polypropylene compound with ground CaCO3 (GCC) and precipitate CaCO3 (PCC) with stearic acid surface coating treatment was used in this study. This product was developed in masterbatch form, which contained 70% GCC in resin and 50% PCC in resin. The resulting (masterbatch pellets) polymer can be spun into fibers through a single-screw extruder. Surface and cross-sectional images of fibers were captured by optical microscopy and scanning electronic microscopy for identifying the organic/inorganic interface of fibers. The melt-spun fibers have a distinctive morphology, the particles impact on spinnability, and productivity in the spunbond will alter the mechanical property, thermal property and optical property of fiber-based products. Processing parameters, including spinning speed, throughput rate and take-up rol...
Separation and Purification Technology, 2021
Fibrous nonwoven filters are widely used in various air filtration applications. Coarse filters a... more Fibrous nonwoven filters are widely used in various air filtration applications. Coarse filters are typically used to protect and extend the lifetime of high-efficiency filters. However, unlike high-efficiency filters, limited work had been carried out to study the evolution of filtration properties and filter structures during the clogging process of coarse fibrous filters due to the lack of non-invasive and non-destructive structural characterization techniques. In this study, a coarse nonwoven filter media with a 94.52% mean porosity value was fabricated. The filtration properties of the studied coarse filter, including pressure drop and filtration efficiency, were found to increase along with the particle loading. The X-ray micro-computed tomography (XMCT) was used to non-invasively characterize the 3D structures of clean and particle-loaded fibrous nonwoven coarse filters at different clogging stages. Although the surface area scanned by XMCT (research of interest, 600*600 µm2)...
Advanced Materials
Theoretical modeling of triboelectric nanogenerators (TENGs) is fundamental to their performance ... more Theoretical modeling of triboelectric nanogenerators (TENGs) is fundamental to their performance optimization, since it can provide useful guidance on the material selection, structure design, and parameter control of relevant systems. Built on the theoretical model of film-based TENGs, here we introduce an analytical model for conductor-to-dielectric contact-mode nonwoven-based TENGs, which copes with the unique hierarchical structure of nonwovens and details the correlation between the triboelectric output (maximum transferred charge density) and nonwoven structural parameters (thickness, solidity, and average fiber diameter). A series of styrene-ethylene-butylene-styrene (SEBS, KratonTM MD1653) nonwoven samples have been fabricated through the melt-blowing process in a pilot-plant setting to map elastomeric nonwoven structural features within certain ranges, while an ion-injection testing protocol is adopted to quantify the triboelectric output with superior consistency and reproducibility. With a database containing structural features and triboelectric output of 43 nonwoven samples, the curve fitting is performed by employing non-linear regression analysis in Python. This model shows good prediction power while suggesting that the triboelectric output of nonwoven-based TENGs reaches a maximum in conductor-to-dielectric contact-mode at a specific thickness, solidity, or average fiber diameter when other structural features are fixed. Lastly, the model also shows a decent prediction performance on polypropylene (PP) meltblown nonwoven system, which verified the universality of the model on meltblown nownoven based TENGs. This article is protected by copyright. All rights reserved.
Journal of Applied Polymer Science, May 14, 2013
Polypropylene (PP) composite filaments containing two different nucleating agents-DMDBS (3 : 2, 4... more Polypropylene (PP) composite filaments containing two different nucleating agents-DMDBS (3 : 2, 4-bis(3,4-dimethyldibenzylidene) sorbitol) and NA11 (sodium 2,2 0-methylene-bis(4,6-di-tertbutylphenyl)-phosphate) were melt spun to modify polymer electrostatic charging characteristics. Sample filaments were charged with a corona instrument and their surface potentials were measured. Initial surface potential as well as potential stability was monitored through an accelerated decay procedure. NA11 was found to be more efficient as an electret additive leading to a 50% increase in charge stability. Filaments with DMDBS exhibited a faster decay. Charging at elevated temperatures resulted in enhanced charge density and stability for both additives. The fiber microstructure was examined by Wide Angle X-ray Diffraction and Differential Scanning Calorimetry. Rather than reducing the crystal sizes, X-Ray diffractograms suggest that the crystal size increases with the addition of nucleating agents, while the degree of crystallinity appears to remain unaltered.
Macromolecular Research, Dec 30, 2015
In this study, surface crystallinity of meltspun polypropylene (PP) filaments was reported. Resul... more In this study, surface crystallinity of meltspun polypropylene (PP) filaments was reported. Results obtained from attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy were confirmed with tapping mode atomic force microscopy (TM-AFM) analysis. ATR-FTIR tests were performed directly on longitudinal surfaces of the filaments, where IR radiation penetrates up to a specific depth. TM-AFM measurements were done on microtomed cross-sections of the filaments, which were scanned carefully to investigate stiffness. Annealing enhanced the surface crystallinity of the filaments in a significant way. Interestingly, samples annealed at 70 and 110 o C for 12 h exhibited similar crystallinity on the uppermost 500 nm surface, whereas for the bulk a continuous increase was observed after XRD studies. 12 h annealing at 70 o C modified the endothermic thermogram, while it did not causes significant effect on overall bulk crystallinity. Differences in the behavior of surface and bulk of the fibrous materials should be considered particularly for surface treatment, i.e. plasma, corona discharge, chemical vapor deposition. Results are also pertinent for water and dye absorbency in polymers.
Water
Anthropogenic activities (e.g., rural urbanization) play major roles in preventing the achievemen... more Anthropogenic activities (e.g., rural urbanization) play major roles in preventing the achievement of sustainable water quality, where eutrophication—the exacerbation of increase in nutrient concentrations combined with warmer temperatures and lower light availability, leading to the dense growth of plant life depleting the amount of available oxygen and killing aquatic life—remains a major challenge for surface water bodies. Filtration mechanisms, with a wide range of applicability, capture common waterborne pathogens as small as 0.1–20.0 μm (bacteria, cysts, spores) and 0.001–0.100 μm (protein, viruses, endotoxins) through the process of microfiltration and ultrafiltration. This study follows the premise of using a designed water flow-through system, with meltblown nonwoven fabrics to measure its performance to capture water contaminant constituents of surface water contamination and eutrophication: total coliforms, nitrate, and orthophosphate. The achieved fabric filtration mecha...
Journal of Applied Polymer Science, 2022
Functional additives, such as mineral and inorganic particles, added significant industrial value... more Functional additives, such as mineral and inorganic particles, added significant industrial value for processing lines such as extrusion and spinning. Within the scope of polymer processing loading mineral additives by compounded mas- terbatch in traditional polyolefin polymers potentially modify those structure bonding by thermal bonding. The large volume of inorganic phase adding raises questions about calcium carbonate as filler in the loading and embossing capacity, quality, and efficient bonding potentiality for relevant products. The process parameters have been recorded around this article on emboss temperature, cal- cium carbonate concentration, web thickness to carry out the hypothesis achiev- able in the spunbond system. Filler adding polypropylene has lower heat capacity, which transfers heat efficiently to achieve optimum bonding effect. Mod- ulated differential scanning calorimeter (MDSC) characterizes heat capacity. Mor- phology of fabric has validated the circumjacent structure changes around the oval pattern. Finally, the conclusion has built a relationship between structure and heat capacity of the inorganic/organic phase, using an equation involving δk ðH,φCaÞ ΔT and the heat capacity correlation with the dosage of CCF.
Smart Textile Coatings and Laminates, 2010
Abstract: Coating and laminating are an essential part of highly functional and technical textile... more Abstract: Coating and laminating are an essential part of highly functional and technical textile development. This chapter discusses general features of coating and laminating process and materials preparations. It also introduces the basic concept of adhesion in the multilayer structure production. Then, the chapter reviews different techniques used to produce coated and laminated fabrics.
Joining Textiles, 2013
Abstract: Coating and laminating are among the best known and oldest techniques to produce compos... more Abstract: Coating and laminating are among the best known and oldest techniques to produce composite or hybrid textiles to achieve functionality and properties that cannot be achieved with single components. General characteristics of coated and laminated fabrics and several of their applications are also discussed.
Smart Textile Coatings and Laminates, 2010
SSRN Electronic Journal, 2021
Polymer, 2018
The work aims at the experimental investigation and theoretical modeling of the physical phenomen... more The work aims at the experimental investigation and theoretical modeling of the physical phenomena responsible for thermal bonding of polymer fibers in nonwovens and their effect on such mechanical properties as the nonwoven stiffness, the yield stress, the stress at failure, toughness, and the entire stress-strain curve. In the experiments two types of
ACS applied materials & interfaces, Jan 9, 2018
Here we describe an electrospun mat of polyvinyl alcohol (PVA) and graphene oxide (GO) as a novel... more Here we describe an electrospun mat of polyvinyl alcohol (PVA) and graphene oxide (GO) as a novel solid-state electrolyte matrix, which offers better performance retention upon drying after infiltrated with aqueous electrolyte. The PVA-GO mat overcomes the major issue of conventional PVA-based electrolytes, which is the ionic conductivity decay upon drying. After exposure to 45±5% relative humidity at 25 ℃ for 1 month, its conductivity decay is limited to 38.4%, whereas that of pure PVA mat is as high as 84.0%. This mainly attributes to the hygroscopic nature of GO and the unique nanofiber structure within the mat. Monolithic supercapacitors have been derived directly on the mat via a well-developed laser-scribing process. The as-prepared supercapacitor offers an areal capacitance of 9.9 mF cmat 40 mV seven after 1-month of aging in ambient conditions, with high device-based volumetric energy density of 0.13 mWh cmand power density of 2.48 W cmrespectively, demonstrating great promi...
ECS Transactions, 2010
The gas diffusion layer (GDL) plays a key role in the overall performance/durability of a polymer... more The gas diffusion layer (GDL) plays a key role in the overall performance/durability of a polymer electrolyte fuel cell (PEFC). Of profound importance, especially in the context of water management and flooding phenomena, is the influence of the underlying pore morphology and wetting characteristics Of the GDL microstructure. In this article, we present the digital volumetric imaging (DVI) technique in order to generate the 3-D carbon paper GD L microstructure. The internal pore structure and the local microstructural variations in terms of fiber alignment and fiberlbinder distributions are investigated using the several 3-D thin sections ofthe sample obtained from DVI.
Macromolecular Research, 2010
Nylon-6 (PA6) nanofiber webs incorporated with boehmite nanoparticles as an electrostatic chargin... more Nylon-6 (PA6) nanofiber webs incorporated with boehmite nanoparticles as an electrostatic charging agent were electrospun and their fiber morphology was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM showed that the median fiber diameter of the PA6 nanofibers was 73 nm and boehmite nanoparticles had little effect on the fiber diameter. The filtration performance of the nanofiber web was measured using 0.3 micron DOP aerosols at a 5.3 cm/s face velocity. Processed and corona charged PA6 nanofiber web showed significant improvement in the submicron aerosol capture efficiency without a change in the air flow resistance compared to the discharged nanofiber web. These results suggest that the electrospinning process imparted electrostatic charge efficiently on the PA6 nanofiber web, and the electrostatic surface potential of a nanofiber web is increased with the incorporation of boehmite nanoparticles.
Journal of Applied Polymer Science, 2011
ABSTRACT
Advanced materials (Deerfield Beach, Fla.), Jan 18, 2015
A simple process for batch or continuous formation of polymer nanofibers and other nanomaterials ... more A simple process for batch or continuous formation of polymer nanofibers and other nanomaterials in the bulk of a sheared fluid medium is introduced. The process could be of high value to commercial nanotechnology as it can be easily scaled up to the fabrication of staple nanofibers at rates that could exceed tens of kilograms per hour.
Textile Research Journal
Spinning technology using melt extrusion and spin-draw processes transforms polymeric materials i... more Spinning technology using melt extrusion and spin-draw processes transforms polymeric materials into highly oriented, crystallized polymeric fibers. Thermoplastic isotactic polypropylene compound with ground CaCO3 (GCC) and precipitate CaCO3 (PCC) with stearic acid surface coating treatment was used in this study. This product was developed in masterbatch form, which contained 70% GCC in resin and 50% PCC in resin. The resulting (masterbatch pellets) polymer can be spun into fibers through a single-screw extruder. Surface and cross-sectional images of fibers were captured by optical microscopy and scanning electronic microscopy for identifying the organic/inorganic interface of fibers. The melt-spun fibers have a distinctive morphology, the particles impact on spinnability, and productivity in the spunbond will alter the mechanical property, thermal property and optical property of fiber-based products. Processing parameters, including spinning speed, throughput rate and take-up rol...
Separation and Purification Technology, 2021
Fibrous nonwoven filters are widely used in various air filtration applications. Coarse filters a... more Fibrous nonwoven filters are widely used in various air filtration applications. Coarse filters are typically used to protect and extend the lifetime of high-efficiency filters. However, unlike high-efficiency filters, limited work had been carried out to study the evolution of filtration properties and filter structures during the clogging process of coarse fibrous filters due to the lack of non-invasive and non-destructive structural characterization techniques. In this study, a coarse nonwoven filter media with a 94.52% mean porosity value was fabricated. The filtration properties of the studied coarse filter, including pressure drop and filtration efficiency, were found to increase along with the particle loading. The X-ray micro-computed tomography (XMCT) was used to non-invasively characterize the 3D structures of clean and particle-loaded fibrous nonwoven coarse filters at different clogging stages. Although the surface area scanned by XMCT (research of interest, 600*600 µm2)...
Advanced Materials
Theoretical modeling of triboelectric nanogenerators (TENGs) is fundamental to their performance ... more Theoretical modeling of triboelectric nanogenerators (TENGs) is fundamental to their performance optimization, since it can provide useful guidance on the material selection, structure design, and parameter control of relevant systems. Built on the theoretical model of film-based TENGs, here we introduce an analytical model for conductor-to-dielectric contact-mode nonwoven-based TENGs, which copes with the unique hierarchical structure of nonwovens and details the correlation between the triboelectric output (maximum transferred charge density) and nonwoven structural parameters (thickness, solidity, and average fiber diameter). A series of styrene-ethylene-butylene-styrene (SEBS, KratonTM MD1653) nonwoven samples have been fabricated through the melt-blowing process in a pilot-plant setting to map elastomeric nonwoven structural features within certain ranges, while an ion-injection testing protocol is adopted to quantify the triboelectric output with superior consistency and reproducibility. With a database containing structural features and triboelectric output of 43 nonwoven samples, the curve fitting is performed by employing non-linear regression analysis in Python. This model shows good prediction power while suggesting that the triboelectric output of nonwoven-based TENGs reaches a maximum in conductor-to-dielectric contact-mode at a specific thickness, solidity, or average fiber diameter when other structural features are fixed. Lastly, the model also shows a decent prediction performance on polypropylene (PP) meltblown nonwoven system, which verified the universality of the model on meltblown nownoven based TENGs. This article is protected by copyright. All rights reserved.