@article{lavoie_rojas_khan_shim_2024, title={Charge Protection in Electret Air Filtration Nonwoven Materials}, volume={4}, ISSN={["2365-709X"]}, url={https://doi.org/10.1002/admt.202301670}, DOI={10.1002/admt.202301670}, abstractNote={AbstractNonwoven media used as electret air filters are often embedded with charges to improve particle capture efficiency. These charged filters are invariably exposed to low surface tension fluids such as oils and alcohols leading to charge loss. In this study, filtration media are endowed with charge protection through increased surface repellency using melt additives that can migrate to the surface during processing. Nonwovens containing fluorochemical melt additives are produced, and examined to determine the relationship between surface chemistry, isopropyl alcohol (IPA) repellency, resultant charge retention, and filtration characteristics. Surface fluorine/carbon (F/C) ratios of ≈0.2 are sufficient to protect filtration performance from vapor discharging methods. Samples with bulk additive loadings of 1.2% or higher are found to achieve the necessary repellency to resist discharging independent of the migration state of the sample, while samples loaded at the 0.6% level required sufficient migration to achieve the requisite F/C ratio of 0.2 in order to be protected. Samples that achieved the necessary surface chemistry to provide significant IPA repellency retained > 80% of electret charge and corresponding filtration performance. These results have special significance in the design of filtration media relevant in global healthcare and other industrial settings.}, journal={ADVANCED MATERIALS TECHNOLOGIES}, author={Lavoie, Joseph and Rojas, Orlando J. and Khan, Saad A. and Shim, Eunkyoung}, year={2024}, month={Apr} }
@article{song_shim_2024, title={High-fidelity 3D simulation of dust-loading behavior and clogging process of coarse nonwoven filter media considering collision effect}, volume={344}, ISSN={["1873-3794"]}, url={https://doi.org/10.1016/j.seppur.2024.127046}, DOI={10.1016/j.seppur.2024.127046}, abstractNote={The filter lifetime of fibrous media is important for the energy-saving application of air filters and efficient delivery of clean air. The clogging process significantly affects the dust-loading behavior of fibrous filter media. Therefore, an effective methodology for determining the deposition of dust particles inside filter structures is necessary. This study conducted numerical dust loading simulations on a three-dimensional (3D) X-ray tomographic structure of coarse nonwoven filter media. Spherical particles with a density of 1808 kg/m3 were used in the simulations instead of plate-like dust particles with a higher silica density. A high-fidelity simulation model was successfully developed by considering collision effects. Key factors were determined, including the Hamaker constant for the adhesion energy, restitution coefficient for the particle kinetic energy, and sliding motion. Remarkably, the deviation between the simulated and experimental dust holding capacity was less than 1 %. The developed simulation model enabled a quantitative evaluation of the clogging process and 3D in-situ evolution of particle deposition and pore structures. It was observed that 95.6 % of the maximum deposited dust mass within the fibrous structure was captured at the clogging point. Several computational methods yielded accurate pore size evaluations and clear 3D pore structure visualizations. The developed methodology for high-fidelity simulation and 3D analysis can be further applied to other two-phase filtration and separation fields, including aerosol filtration, coalescence filtration, membrane fouling, micro/nanoplastic capture, and oil/water separation.}, journal={SEPARATION AND PURIFICATION TECHNOLOGY}, author={Song, Yu and Shim, Eunkyoung}, year={2024}, month={Sep} }
@article{aragon_sanchez_zimeri_shim_fang_young_2024, title={TiO2-Coated Meltblown Nonwoven Fabrics Prepared via Atomic Layer Deposition for the Inactivation of E. coli as a Model Photocatalytic Drinking Water Treatment System}, volume={11}, ISSN={["2076-3298"]}, url={https://doi.org/10.3390/environments11050092}, DOI={10.3390/environments11050092}, abstractNote={The controlled manufacturing of semiconductor photocatalysts is crucial to their development for drinking water treatment. In this study, TiO2-coated meltblown nonwoven fabrics prepared via Atomic Layer Deposition (ALD) are applied for the inactivation of Escherichia coli (E. coli). It is observed that in the presence of an ultraviolet light-emitting diode (UV-LED) light source (255 nm), 1.35 log E. coli inactivation is achieved. However, exposure to catalyst-coated fabrics in addition to the light source resulted in >4 log E. coli inactivation, suggesting a much higher rate of hydroxyl radical formation on the surface, leading to cell death.}, number={5}, journal={ENVIRONMENTS}, author={Aragon, Alexander G. and Sanchez, Jaime A. Cardenas and Zimeri, Carlos and Shim, Eunkyoung and Fang, Xiaomeng and Young, Kyana R. L.}, year={2024}, month={May} }
@article{sanchez_szewczyk_assaad_zimeri_shim_fang_young_2023, title={Use of Meltblown Nonwoven Fabric Filter for Stormwater Runoff Treatment}, volume={15}, ISSN={["2073-4441"]}, url={https://doi.org/10.3390/w15020242}, DOI={10.3390/w15020242}, abstractNote={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 mechanism showed capture of total coliforms (59%), nitrate (51%), and orthophosphate (46%). The current study provides an alternative solution to more common and traditional water treatment technologies, such as chlorine and ozone disinfection, which (1) introduces disinfection or treatment byproducts and (2) cannot adapt to the permanent changing conditions and newer environmental challenges.}, number={2}, journal={WATER}, author={Sanchez, Jaime A. Cardenas and Szewczyk, Hunter and Assaad, Judy and Zimeri, Carlos and Shim, Eunkyoung and Fang, Xiaomeng and Young, Kyana R. L.}, year={2023}, month={Jan} }
@article{song_shim_2022, title={3D X-ray tomographic microstructure analysis of dust-clogging inside nonwoven fibrous filter media}, volume={664}, ISSN={["1873-3123"]}, url={https://doi.org/10.1016/j.memsci.2022.121067}, DOI={10.1016/j.memsci.2022.121067}, abstractNote={Clogging inside fibrous filter media largely affects the particle loading characteristics of filter media. The three-dimensional (3D) analysis of particle deposits that form clogging is thus necessary. Compact nonwoven fibrous filter media with thick-fiber was fabricated using meltblown technology. Filter media with the deposited dust mass was scanned with X-ray μ-CT imaging. Methodology of image processing and image analysis was developed to open the black box of loaded fibrous filter media. Quantitative microstructure analysis was conducted including pristine fibrous structure analysis, quadrant structure analysis, depth distribution of particles, and size distribution of 3D particle deposits. Quadrant analysis revealed that deposited dust mass was negatively correlated with quadrant fiber solidity. A considerably large volume of particle deposits formed face-region (in the depth of 0–200 μm) clogging inside the filter structure. Higher-basis-weight filter media exhibited more particle deposition in deeper filter depth. Watershed-segmentation-based size distribution statistics revealed that more volume of large connected particle agglomerates and larger constituent individual particles existed inside higher-basis-weight filter media.}, journal={JOURNAL OF MEMBRANE SCIENCE}, author={Song, Yu and Shim, Eunkyoung}, year={2022}, month={Dec} }
@article{ruckdashel_shim_2022, title={Hollowness Variation with Die Wall Thickness in Melt-Spinning of Polypropylene Hollow Fibers}, volume={4}, ISSN={["1875-0052"]}, DOI={10.1007/s12221-022-4498-0}, journal={FIBERS AND POLYMERS}, author={Ruckdashel, Rebecca and Shim, Eunkyoung}, year={2022}, month={Apr} }
@article{wei_shim_song_pourdeyhimi_2022, title={Synthesizing heat transfer factors on thermal bonding structure of mineral added polypropylene spun-bond}, volume={139}, ISSN={["1097-4628"]}, url={https://doi.org/10.1002/app.52138}, DOI={10.1002/app.52138}, abstractNote={AbstractFunctional 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 masterbatch 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, calcium carbonate concentration, web thickness to carry out the hypothesis achievable in the spunbond system. Filler adding polypropylene has lower heat capacity, which transfers heat efficiently to achieve optimum bonding effect. Modulated differential scanning calorimeter (MDSC) characterizes heat capacity. Morphology 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 and the heat capacity correlation with the dosage of CCF.}, number={19}, journal={JOURNAL OF APPLIED POLYMER SCIENCE}, publisher={Wiley}, author={Wei, Wei and Shim, Eunkyoung and Song, Yu and Pourdeyhimi, Behnam}, year={2022}, month={Jan} }
@article{barilovits_khan_shim_2021, title={Experimental Investigation of the Fiber Formation Process and Web Structures Using an Annular Meltblowing Spinneret}, volume={60}, ISSN={["0888-5885"]}, url={https://doi.org/10.1021/acs.iecr.1c01080}, DOI={10.1021/acs.iecr.1c01080}, abstractNote={This research experimentally investigates the fiber and web formation process of an array of annular meltblown spinnerets. In this design, the molten polymer is extruded from an array of outlets, each of which is individually surrounded by a concentric high-velocity heated air stream. With its multirow capability, it potentially becomes a high-productivity microfiber fabrication process. We experimentally investigate the effects of critical processing parameters and material properties on the fiber and web formation process. First, the polymer thermal and rheological behavior is presented. Next, a detailed three-dimensional air temperature and velocity profile, measured in the absence of spinning fibers, is presented for an array of supplied temperatures and internal machine air pressures. Web analysis in relation to this air profile shows that smaller fibers in cooler air streams require shorter die-collector distances to form bonded fabrics. Calculations are then made that show polymer spinning temperature is largely determined by air temperature, a distinguishing feature of this meltblowing design. Finally, a full factorial variation of air temperature, air speed, and polymer throughput is shown that relates processing conditions to fiber diameter distribution. Median diameters are well described by an empirical model and ranged from less than 1 μm to almost 14 μm.}, number={37}, journal={INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH}, publisher={American Chemical Society (ACS)}, author={Barilovits, Stephen and Khan, Saad A. and Shim, Eunkyoung}, year={2021}, month={Sep}, pages={13627–13636} }
@article{jafari_shim_joijode_2021, title={Fabrication of Poly(lactic acid) filter media via the meltblowing process and their filtration performances: A comparative study with polypropylene meltblown}, volume={260}, ISSN={["1873-3794"]}, DOI={10.1016/j.seppur.2020.118185}, abstractNote={Poly(Lactic acid) (PLA) is considered as a promising alternative for petroleum-based synthetic plastic under the rising concerns over the environmental sustainability of polypropylene (PP) filter materials. To adapt PLA for the meltblown filter media production, it is necessary to establish how PLA polymer properties affect the meltblown process, media structure and filtration performance. We investigated the processability and effects of processing parameters on PLA meltblown structures and filtration performances in an industrially relevant setting by utilizing a commercially available low molecular weight PLA resin and a Reicofil meltblowing production line. We were able to fabricate PLA meltblown media comparable with PP meltblown media both in structures and filtration performances. Increasing airflow rate and decrease throughput reduced fiber diameter of PLA meltblown, but at the given processing condition, PLA meltblown tends to have larger fiber diameters than PP meltblown. However, larger diameter did not deteriorate the filtration efficiency of PLA meltblown. Interestingly, the filtration efficiency of PLA meltblown is higher than those of PP meltblown with similar fiber diameters. We also found the solidity of PLA meltblown lower than that of PP meltblown. This further improved filtration performance by improving air permeability. The quality factors of PLA meltblowns were more than double of PP meltblowns' quality factors when fiber sizes are similar. PLA also exhibited comparable chargeability and charge stability with PP when corona charged.}, journal={SEPARATION AND PURIFICATION TECHNOLOGY}, author={Jafari, Mehran and Shim, Eunkyoung and Joijode, Abhay}, year={2021}, month={Apr} }
@article{wang_shim_he_pourdeyhimi_gao_2021, title={Modeling the Triboelectric Behaviors of Elastomeric Nonwoven Fabrics}, volume={11}, ISSN={["1521-4095"]}, url={https://doi.org/10.1002/adma.202106429}, DOI={10.1002/adma.202106429}, abstractNote={AbstractTheoretical 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, an analytical model is introduced 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 nonwoven samples are fabricated through a melt‐blowing process to map nonwoven structural features within certain ranges, while an ion‐injection 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, a good model fitting is achieved via nonlinear regression analysis in Python, which also shows good predictive power and suggests the existing of tribo‐output maxima at a specific thickness, solidity, or average fiber diameter when other structural parameters are fixed. The model is also successfully applied to a group of polypropylene meltblown nonwovens, which verifies its universality on meltblown‐nonwoven‐based TENGs.}, journal={ADVANCED MATERIALS}, publisher={Wiley}, author={Wang, Yanan and Shim, Eunkyoung and He, Nanfei and Pourdeyhimi, Behnam and Gao, Wei}, year={2021}, month={Nov} }
@article{song_shim_2021, title={Structure characterization of the clogging process of coarse fibrous filter media during solid particle loading with X-ray micro-computed tomography}, volume={273}, ISSN={["1873-3794"]}, DOI={10.1016/j.seppur.2021.118980}, abstractNote={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) was a tiny spot on the whole filter media, this surface area exhibited good representativeness of the average structural properties of the whole filter media, e.g., porosity in this study. Depth profiles of local porosity and particle solidity across the full thickness of filter XMCT image indicated that at the beginning of particle loading stages, particles were captured and trapped by the top part of filter thickness, which was corresponded to the reported clogging process of high-efficiency filters. Then particles could be found across the full filter thickness. However, during the transitioning from the depth filtration stage to the surface filtration stage, clogging with high particle solidity was found in the bottom part of filter thickness. As more particles were loaded, clogging was found in both the middle and bottom parts. After that, the top part would be clogged, and the surface cake would start forming thereafter. This is the first report of the clogging process of the fibrous nonwoven coarse filter. Pore diameter distribution derived from the pore skeleton network via skeletonization of the 3D particle-loaded filter structures also described the same structure evolution during dust loading.}, journal={SEPARATION AND PURIFICATION TECHNOLOGY}, author={Song, Yu and Shim, Eunkyoung}, year={2021}, month={Oct} }
@misc{wei_shim_barnes_pourdeyhimi_2021, title={Structure-property relationship of melt spinning polypropylene fibers containing inorganic particulate CaCO3 fillers}, volume={91}, ISSN={["1746-7748"]}, url={https://doi.org/10.1177/0040517520982001}, DOI={10.1177/0040517520982001}, abstractNote={ 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 roll velocity, were systematically study to understand the structure formation. Meanwhile, different loading concentrations are applied for varied factor comparison of particle size and shape. The Weibull distribution model is applied for determining the tensile property of fibers containing high GCC dosages of 20–40%. Meanwhile, a few more steps of gauge length are utilized for studying the probability of a weak link in polymer materials. Through a systematic discussion of the GCC and PCC comparison study in changing fiber properties, the impact of the particle size on agglomeration formation is emphasized, as well as the breaking mechanism of fibers. }, number={11-12}, journal={TEXTILE RESEARCH JOURNAL}, author={Wei, Wei and Shim, Eunkyoung and Barnes, William and Pourdeyhimi, Behnam}, year={2021}, month={Jun}, pages={1419–1435} }
@article{yin_shim_denhartog_2020, title={A Study of Skin Physiology, Sensation and Friction of Nonwoven Fabrics Used in Absorbent Hygiene Products in Neutral and Warm Environments}, volume={24}, ISSN={2352-5738}, url={http://dx.doi.org/10.1016/j.biotri.2020.100149}, DOI={10.1016/j.biotri.2020.100149}, abstractNote={Absorbent hygiene products like diapers, feminine hygiene, and wet wipes are life necessities. These products commonly use nonwoven fabrics as the layer that is in contact with the skin. Their performance in terms of skin health and comfort is receiving increased attention because of the existence of concerns for skin health issues such as skin irritation and dermatitis, and the large influence of skin sensation on individuals' preference. Friction is usually recognized as an important factor for skin comfort and dermatitis issues, but there is a lack of understanding of the relationship between friction and skin physiology, skin sensation, in the use of absorbent hygiene products. This study reports a measurement of friction in vivo with the evaluation of skin physiology and sensation in neutral and warm environments to explore the effects of fabric and friction on skin comfort. Friction tests between the volar forearm and nonwoven fabrics were conducted with the measurement of transepidermal water loss, skin redness, and the evaluation of subjective skin sensation. The interaction between skin and eight nonwoven fabrics with a surface roughness (arithmetic mean height) between 3 μm and 20 μm was evaluated in neutral (22 °C) and warm (35 °C) environments. Skin physiological changes after friction were able to be detected quantitatively by the transepidermal water loss and skin redness measurement. In the warm environment, there was significantly higher friction, less pleasantness, more changes in transepidermal water loss but not in skin redness. The friction can only relate to skin physiology and sensation in the neutral environment while the surface roughness of fabrics related to them in both neutral and warm environments. Both rough and smooth fabrics caused high friction in the warm environment, but the rough fabric caused a higher adverse impact on skin physiology and sensation than smooth fabrics that suggested the adhesion and deformation friction could have different effects on skin comfort. Deformation friction is more likely to have effects on skin physiology and pleasantness sensation than adhesion friction. The pleasantness sensation has a negative relationship with skin physiology. A more unpleasant sensation can indicate more impact on skin physiology. This provides a potential that the unpleasant sensation can be a precaution signal for the adverse effects on skin physiology.}, journal={Biotribology}, publisher={Elsevier BV}, author={Yin, Lanjun and Shim, Eunkyoung and DenHartog, Emiel}, year={2020}, month={Dec}, pages={100149} }
@article{ruckdashel_shim_2020, title={Effects of melt spinning parameters on polypropylene hollow fiber formation}, volume={15}, url={https://doi.org/10.1177/1558925019899680}, DOI={10.1177/1558925019899680}, abstractNote={ The objective of this research was to explore the effects of processing conditions on hollow fiber spinning, specifically to look at how differences in solidification impact hollow and solid fiber structures. Polypropylene hollow fibers were melt-spun with a four-segmented arc (4C) die under the wide ranges of spinning conditions (0.25–0.83 g/min of polymer mass throughput per a fiber, 500–2000 m/min of spinning speed, and 5%–100% quench rate). Fiber structure was explored through thermal, geometric, and tensile properties. Fiber hollowness depends on all spinning parameters studied (mass throughput, spinning speed, and quench rate). Increasing the quench rate resulted in the fiber solidifications closer to the spinneret. This leads to higher hollowness but also affected fiber tensile properties. When hollow and solid fibers were compared at constant quench, the hollow fiber solidified faster than solid fiber. The crystallinity of the fibers remained similar, but the tensile modulus was higher for hollow fiber than for solid fiber. }, journal={Journal of Engineered Fibers and Fabrics}, publisher={SAGE Publications}, author={Ruckdashel, Rebecca and Shim, Eunkyoung}, year={2020}, month={Jan}, pages={155892501989968} }
@article{lavoie_rojas_khan_shim_2020, title={Migration Effects of Fluorochemical Melt Additives for Alcohol Repellency in Polypropylene Nonwoven Materials}, volume={12}, url={https://doi.org/10.1021/acsami.0c10144}, DOI={10.1021/acsami.0c10144}, abstractNote={The use of bulk polymer melt additives provides a facile, industrially relevant approach to tailor properties of polymer surfaces for many different applications. These melt additives, when blended with polymers prior to melt spinning, migrate to the fiber surface and influence surface functionality. While the use of bulk polymer melt additives to impart hydrophilicity or oleophobicity is well studied, the impact of the fiber formation process on additive migration and resultant repellency of nonwoven media products remains largely unexplored. In this study, we produce fluorochemical melt additive containing meltblown nonwovens, and establish methods for characterization of fiber mat surface composition and repellency. Repellency of low surface tension fluids is a significant challenge, and is of particular importance in the creation of medical garments such as surgical gowns and masks which must perform as liquid barriers even when exposed to alcohol based solutions. Similarly, melt additives are also used in the production of electret air filtration devices. Electret filters are imbued with charges in order to enhance particle capture performance, but this charge can be negated through wetting by low surface tension fluids. To address this challenge, the changing composition of fiber surfaces due to the migration of additives is monitored via X-ray Photoelectron Spectroscopy (XPS), then related to repellency of alcohol solutions by contact angle analysis. We demonstrate that for the samples tested a fluorine to carbon (F/C) ratio of 0.35 is sufficient to prevent wicking of isopropanol droplets, and higher surface tension fluids could be repelled by fiber mats with lower fluorine content. Through the use of cross-sectional ToF-SIMS analysis, we find that migration of additives is key to the performance of samples with low additive loadings, and that these phenomena are heavily influenced by many nonwoven manufacturing parameters including fiber size, die-to-collector distance, and polymer resin melt flow rates.}, number={32}, journal={ACS Applied Materials & Interfaces}, publisher={American Chemical Society (ACS)}, author={Lavoie, Joseph H. and Rojas, Orlando J. and Khan, Saad A. and Shim, Eunkyoung}, year={2020}, month={Aug}, pages={36787–36798} }
@article{yu_shim_2021, title={Process‐structure‐property relationship of meltblown poly (styrene–ethylene/butylene–styrene) nonwovens}, url={https://doi.org/10.1002/app.50230}, DOI={10.1002/app.50230}, abstractNote={AbstractWith the advance of the thermoplastic plastic elastomer (TPE) technology, there are growing interest and needs for using these materials in the meltblowing process where benefits of small fiber diameters of meltblowns can be combined with rubber‐like elastic properties of elastomers. Performances and utilities of wide ranges of meltblown products such as facemask, medical barrier, wound‐care, diaper can be drastically improved with additions of TPE. In this study, a new elastomeric meltblown fabric was successfully made with the styrene–ethylene/butylene–styrene (SEBS) block copolymer, and the relationship among structure, tensile properties, and meltblowing process parameters are studied. We found that median fiber diameter increases with the polymer mass throughout and decreases with air pressure, and fabric solidity has significantly influenced by die collector distance (DCD). The pore sizes of the fabrics are directly influenced by fiber diameters at the given DCD, but higher DCD increases the pore size due to their open structures. All SEBS nonwovens exhibit high strain at break, larger than 400%. Processing parameters significantly affect tensile properties, and this can be attributed to the fabric structure changes. The reduction of fiber diameter tends to increase the tensile strength of the fabric as it created more fiber‐to‐fiber bond points.}, journal={Journal of Applied Polymer Science}, author={Yu, Yang and Shim, Eunkyoung}, year={2021}, month={Apr} }
@article{shim_2019, title={Coating and laminating processes and techniques for textiles}, ISBN={["978-0-08-102428-7"]}, DOI={10.1016/B978-0-08-102428-7.00002-X}, abstractNote={Coating and laminating are an essential part of highly functional and technical textile developments. 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.}, journal={SMART TEXTILE COATINGS AND LAMINATES, 2ND EDITION}, author={Shim, E.}, year={2019}, pages={11–45} }
@article{pan_tong_he_liu_shim_pourdeyhimi_gao_2018, title={Electrospun Mat of Poly(vinyl alcohol)/Graphene Oxide for Superior Electrolyte Performance}, volume={10}, ISSN={["1944-8252"]}, DOI={10.1021/acsami.7b14498}, abstractNote={Here, we describe an electrospun mat of poly(vinyl 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 °C 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 cm-2 at 40 mV s-1 even after 1 month of aging under ambient conditions, with a high device-based volumetric energy density of 0.13 mWh cm-3 and a power density of 2.48 W cm-3, demonstrating great promises as a more stable power supply for wearable electronics.}, number={9}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Pan, Qin and Tong, Ningjun and He, Nanfei and Liu, Yixin and Shim, Eunkyoung and Pourdeyhimi, Behnam and Gao, Wei}, year={2018}, month={Mar}, pages={7927–7934} }
@article{zhang_staszel_yarin_shim_pourdeyhimi_2018, title={Point-bonded polymer nonwovens and their rupture in stretching}, volume={146}, ISSN={["1873-2291"]}, DOI={10.1016/j.polymer.2018.05.024}, abstractNote={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 nonwovens were explored: Polybutylene Terephthalate (PBT) nonwoven and Polybutylene Terephthalate (PBT)/Polyethylene (PE) (80/20) nonwoven. Special attention was paid to the effect of the bonding pattern (e.g. circular or rhombic) on the nonwoven failure patterns in stretching. It was shown that failure happens at the periphery of stiffened bonds. A theory of this phenomenon is given which predicted tensile stress concentration up to 140% of the applied tensile stress in that area, which was responsible for the failure modes observed experimentally.}, journal={POLYMER}, author={Zhang, Wenshuo and Staszel, Christopher and Yarin, Alexander L. and Shim, Eunkyoung and Pourdeyhimi, Behnam}, year={2018}, month={Jun}, pages={209–221} }
@article{pan_shim_pourdeyhimi_gao_2017, title={Highly Conductive Polypropylene-Graphene Nonwoven Composite via Interface Engineering}, volume={33}, ISSN={["0743-7463"]}, DOI={10.1021/acs.langmuir.7b01508}, abstractNote={Here we report a highly conductive polypropylene-graphene nonwoven composite via direct coating of melt blown polypropylene (PP) nonwoven fabrics with graphene oxide (GO) dispersions in N,N-dimethylformamide (DMF), followed by the chemical reduction of GO with hydroiodic acid (HI). GO as an amphiphilic macromolecule can be dispersed in DMF homogeneously at a concentration of 5 mg/mL, which has much lower surface tension (37.5 mN/m) than that of GO in water (72.9 mN/m, at 5 mg/mL). The hydrophobic PP nonwoven has a surface energy of 30.1 mN/m, close to the surface tension of GO in DMF. Therefore, the PP nonwoven can be easily wetted by the GO/DMF dispersion without any pretreatment. Soaking PP nonwoven in a GO/DMF dispersion leads to uniform coatings of GO on PP-fiber surfaces. After chemical reduction of GO to graphene, the resulting PP/graphene nonwoven composite offers an electrical conductivity of 35.6 S m-1 at graphene loading of 5.2 wt %, the highest among the existing conductive PP systems reported, indicating that surface tension of coating baths has significant impact on the coating uniformity and affinity. The conductivity of our PP/graphene nonwoven is also stable against stirring washing test. In addition, here we demonstrate a monolithic supercapacitor derived from the PP-GO nonwoven composite by using a direct laser-patterning process. The resulted sandwich supercapacitor shows a high areal capacitance of 4.18 mF/cm2 in PVA-H2SO4 gel electrolyte. The resulting highly conductive or capacitive PP/graphene nonwoven carries great promise to be used as electronic textiles.}, number={30}, journal={LANGMUIR}, author={Pan, Qin and Shim, Eunkyoung and Pourdeyhimi, Behnam and Gao, Wei}, year={2017}, month={Aug}, pages={7452–7458} }
@article{pan_shim_pourdeyhimi_gao_2017, title={Nylon-Graphene Composite Nonwovens as Monolithic Conductive or Capacitive Fabrics}, volume={9}, ISSN={["1944-8244"]}, DOI={10.1021/acsami.7b00471}, abstractNote={Here we describe a nylon-graphene nonwoven (NGN) composite, prepared via melt-blowing of nylon-6 into nonwoven fabrics and infiltrate those with graphene oxide (GO) in aqueous dispersions, which were further chemically reduced into graphene to offer electrical conductivity. The correlation between the conductivity and the graphene loading is described by the percolation scaling law σ = (p - pc)t, with an exponent t of 1.2 and a critical concentration pc of 0.005 wt %, the lowest among all the nylon composites reported. Monolithic supercapacitors have been further developed on the nylon-GO nonwoven composites (NGO), via a programed CO2-laser patterning process. The nylon nonwoven works as an efficient matrix, providing high capacity to GO and ensuring enough electrode materials generated via the subsequent laser patterning processes. Our best monolithic supercapacitors exhibited an areal capacitance of 10.37 mF cm-2 in PVA-H2SO4 electrolyte, much higher than the 1-3 mF cm-2 reported for typical microsupercapacitors. Moreover, our supercapacitors were able to retain a capacitance density of 5.07 mF cm-2 at an ultrahigh scan rate (1 V s-1), probably due to the facilitated ion migration within the highly porous nonwoven framework. This is the first report of highly functional nylon-6 nonwovens, fabricated via industrially scalable pathways into low-cost conductive polymer matrices and disposable energy storage systems.}, number={9}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Pan, Qin and Shim, Eunkyoung and Pourdeyhimi, Behnam and Gao, Wei}, year={2017}, month={Mar}, pages={8308–8316} }
@article{kilic_russell_shim_pourdeyhimi_2017, title={The charging and stability of electret filters}, journal={Fibrous filter media}, author={Kilic, A. and Russell, S. and Shim, E. and Pourdeyhimi, B.}, year={2017}, pages={95–121} }
@article{kilic_shim_pourdeyhimi_2016, title={Effect of annealing on charging properties of electret fibers}, volume={7}, DOI={10.1080/00405000.2016.1207269}, abstractNote={Abstract In the present work, effect of annealing on charging and surface morphology of isotactic polypropylene (PP) filaments was reported. To enhance the surface crystallinity of the filaments, samples were annealed at 70 and 110 °C for 12 h. As expected, fiber surface crystallinity increased upon annealing which led more stable electret fibers. However, the change in the initial surface potential was not so remarkable. The same trend was also observed in filaments containing a commercial nucleating agent, NA11 (sodium 2,2′-methylene-bis(4,6-di-tertbutylphenyl)-phosphate). Surface crystallinity was analyzed using the intensity of specific peaks obtained from attenuated total reflection infrared spectroscopy analysis. The surface charge characteristics of fibers were determined using a modified surface potential decay test.}, number={6}, journal={The Journal of The Textile Institute}, publisher={Informa UK Limited}, author={Kilic, Ali and Shim, Eunkyoung and Pourdeyhimi, Behnam}, year={2016}, month={Jul}, pages={1–5} }
@article{shim_pourdeyhimi_shiffler_2016, title={Process-structure-property relationship of melt spun poly(lactic acid) fibers produced in the spunbond process}, volume={133}, ISSN={["1097-4628"]}, DOI={10.1002/app.44225}, abstractNote={ABSTRACTWe report on the process–structure–property relationships for Poly(lactic acid) (PLA) filaments produced through the spunbond process. The influence of spinning speed, polymer throughput, and draw ratio on crystallinity and birefringence of fibers were evaluated. We established that increasing spinning speed increases crystallinity and birefringence of fibers. We also investigate the role of fiber structures on fiber tensile properties—breaking tensile strength, strain at break, initial modulus, and natural draw ratio. An increase in spinning speed leads to a higher breaking tensile strength, higher initial modulus and lower strain at break. We have shown an almost linear relationship between breaking tensile strength of PLA fibers and birefringence. This indicates that improved tensile properties at high spinning speeds can be attributed to enhanced molecular orientation. The dependency of fiber breaking tensile strength and strain at break on spun orientation were explained with natural draw ratio, as a measure of spun orientation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44225.}, number={47}, journal={JOURNAL OF APPLIED POLYMER SCIENCE}, publisher={Wiley-Blackwell}, author={Shim, Eunkyoung and Pourdeyhimi, Behnam and Shiffler, Don}, year={2016}, month={Dec} }
@article{venu_shim_anantharamaiah_pourdeyhimi_2016, title={Structures and properties of hydroentangled nonwovens: effect of number of manifolds}, volume={4}, DOI={10.1080/00405000.2016.1165400}, abstractNote={Hydroentangling is a process in which fibers are entangled by impinging of a curtain of high-speed water jets to form mechanically strong, soft, and textile-like fabrics. Hydroentangled nonwovens are finding a gamut of applications without knowing the entangling mechanisms. In most applications, hydroentangling is carried out using multiple manifolds. This study focuses on the formation of hydroentangled web structures with multiple manifolds and their properties. The 3D analysis revealed the internal structures of hydroentangled nonwovens disclosing formation of fiber loops at jet impact regions. We also report changes of fiber orientations and fiber interlocking within web structures in nonwovens hydroentanged with multiple manifolds.}, number={3}, journal={The Journal of The Textile Institute}, publisher={Informa UK Limited}, author={Venu, Lalith B. Suragani and Shim, Eunkyoung and Anantharamaiah, Nagendra and Pourdeyhimi, Behnam}, year={2016}, month={Apr}, pages={1–15} }
@article{kilic_shim_pourdeyhimi_2015, title={Electrostatic Capture Efficiency Enhancement of Polypropylene Electret Filters with Barium Titanate}, volume={49}, ISSN={["1521-7388"]}, DOI={10.1080/02786826.2015.1061649}, abstractNote={This study reports on the effects of BaTiO3—a high dielectric constant additive—addition on charging and filtration properties of meltblown polypropylene (PP) electret filters. Since electrostatic capture efficiency of electret filters is mainly dependent on electrical forces, surface potential and aerosol filtration properties were analyzed and compared. Due to quasi-permanent nature of electret property, stability of charging and filtration performance was also investigated via following an isothermal charge decay procedure. Addition of BaTiO3 did not alter fiber morphology significantly. Particularly, the stability of electrostatic filtration performance was found to be promising with the addition of BaTiO3. Possible microstructural changes after addition of BaTiO3 were investigated via wide angle X-ray diffraction. Changes in crystal structure of PP upon addition of BaTiO3 did not deteriorate electrostatic properties. Copyright 2015 American Association for Aerosol Research}, number={8}, journal={AEROSOL SCIENCE AND TECHNOLOGY}, publisher={Informa UK Limited}, author={Kilic, Ali and Shim, Eunkyoung and Pourdeyhimi, Behnam}, year={2015}, month={Aug}, pages={666–673} }
@misc{kilic_shim_pourdeyhimi_2015, title={Measuring electrostatic properties of fibrous materials: A review and a modified surface potential decay technique}, volume={74}, ISSN={["1873-5738"]}, DOI={10.1016/j.elstat.2014.12.007}, abstractNote={Electrostatic charging of fibrous materials are of concern for the performance of electret filters and comfort issues of textiles. However there is a huge controversy in the characterization techniques of ion beam irradiated or corona charged fibrous materials. In this study we reported a reliable, simple surface potential measurement method. Large variations in potential measurements were found to be mostly due to structural nonuniformity such as packing density, thickness and fiber–fiber proximity. Test samples were prepared after optimizing those parameters and we were able to reduce coefficient of variation below 15%. Methods that were developed so far were also reviewed.}, journal={JOURNAL OF ELECTROSTATICS}, publisher={Elsevier BV}, author={Kilic, Ali and Shim, Eunkyoung and Pourdeyhimi, Behnam}, year={2015}, month={Apr}, pages={21–26} }
@article{smoukov_tian_vitchuli_gangwal_geisen_wright_shim_marquez_fowler_velev_et al._2015, title={Scalable Liquid Shear-Driven Fabrication of Polymer Nanofibers}, volume={27}, ISSN={["1521-4095"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84928028957&partnerID=MN8TOARS}, DOI={10.1002/adma.201404616}, abstractNote={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 may be of high value to commercial nanotechnology, as it can be easily scaled up to the fabrication of staple nanofibers at rates that may exceed tens of kilograms per hour.}, number={16}, journal={ADVANCED MATERIALS}, publisher={Wiley-Blackwell}, author={Smoukov, S.K. and Tian, T. and Vitchuli, N. and Gangwal, S. and Geisen, P. and Wright, M. and Shim, E. and Marquez, M. and Fowler, J. and Velev, Orlin and et al.}, year={2015}, month={Apr}, pages={2642–2647} }
@article{kilic_jones_shim_pourdeyhimi_2016, title={Surface crystallinity of meltspun isotactic polypropylene filaments}, volume={24}, ISSN={["2092-7673"]}, DOI={10.1007/s13233-016-4011-y}, number={1}, journal={MACROMOLECULAR RESEARCH}, publisher={Springer Science \mathplus Business Media}, author={Kilic, Ali and Jones, Keith and Shim, Eunkyoung and Pourdeyhimi, Behnam}, year={2016}, month={Jan}, pages={25–30} }
@article{kilic_shim_pourdeyhimi_yeom_2014, title={Aerosol Filtration Properties of Nucleating Agent Containing Electret Filters}, volume={54}, ISSN={["1548-2634"]}, DOI={10.1002/pen.23693}, abstractNote={This study reports on the effects of nucleating agents on morphology, charging, and electrostatic filtration performance of polypropylene meltblown webs. Two commercial nucleating agents, DMDBS (3:2, 4‐bis(3,4‐dimethyldibenzylidene) sorbitol) and NA11 (sodium 2,2′‐methylene‐bis(4,6‐di‐tertbutylphenyl)‐phosphate) were compared. It is hypothesized that faster solidification brought about by the addition of the nucleating agents may be responsible for the slight increase in fiber diameter and concomitant reduction in web solidity. Samples were charged at room temperature as well as at elevated temperatures. Upon thermal charging, significant enhancement in the electrostatic potential and filtration performance of the webs was observed. Particularly, the stability of electrostatic filtration performance was found to be promising with the addition of these polarizable additives. Dielectric spectroscopy tests confirmed an increase in capacitance for samples containing nucleating agents. POLYM. ENG. SCI., 54:1533–1539, 2014. © 2013 Society of Plastics Engineers}, number={7}, journal={POLYMER ENGINEERING AND SCIENCE}, publisher={Wiley-Blackwell}, author={Kilic, Ali and Shim, Eunkyoung and Pourdeyhimi, Behnam and Yeom, Bong-Yeol}, year={2014}, month={Jul}, pages={1533–1539} }
@article{amirnasr_shim_yeom_pourdeyhimi_2014, title={Basis weight uniformity analysis in nonwovens}, volume={105}, ISSN={["1754-2340"]}, DOI={10.1080/00405000.2013.820017}, abstractNote={It is widely recognized that nonwoven basis weight uniformity affects various properties of nonwovens, including appearance, physical properties, or mechanical properties. However, it is one of the nonwoven characteristics that is most difficult to characterize. This paper reports on the methodology based on the well-known quadrant method that objectively quantifies uniformity of nonwoven fabrics.}, number={4}, journal={JOURNAL OF THE TEXTILE INSTITUTE}, publisher={Informa UK Limited}, author={Amirnasr, Elham and Shim, Eunkyoung and Yeom, Bong-Yeol and Pourdeyhimi, Behnam}, year={2014}, month={Apr}, pages={444–453} }
@article{kilic_shim_yeom_pourdeyhimi_2013, title={Effect of DMDBS (3: 2, 4-bis(3,4-dimethyldibenzylidene) sorbitol) and NA11 (sodium 2,2-methylene-bis(4,6-di-tertbutylphenyl)-phosphate) on electret properties of polypropylene filaments}, volume={130}, ISSN={["1097-4628"]}, DOI={10.1002/app.39392}, abstractNote={ABSTRACTPolypropylene (PP) composite filaments containing two different nucleating agents—DMDBS (3 : 2, 4‐bis(3,4‐dimethyldibenzylidene) sorbitol) and NA11 (sodium 2,2′‐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. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2068–2075, 2013}, number={3}, journal={JOURNAL OF APPLIED POLYMER SCIENCE}, publisher={Wiley-Blackwell}, author={Kilic, Ali and Shim, Eunkyoung and Yeom, Bong Yeol and Pourdeyhimi, Behnam}, year={2013}, month={Nov}, pages={2068–2075} }
@article{suragani venu_shim_anantharamaiah_pourdeyhimi_2013, title={Impacts of high-speed waterjets on web structures}, volume={105}, ISSN={0040-5000 1754-2340}, url={http://dx.doi.org/10.1080/00405000.2013.819613}, DOI={10.1080/00405000.2013.819613}, abstractNote={Hydroentangling, where a fabric is formed by striking of fine, closely spaced, high speed waterjets, is one of the fastest growing bonding methods in the nonwoven industry. Softness, drape, conformability, and relatively high strength are the major characteristics that make this bonding technology unique. Despite the method appeal, few understand the impact of waterjet on fabric structures. The primary function of waterjet is to produce fiber entangling, which induces web integrity. In this paper, we have analyzed the interaction of waterjets on web structures to provide a better understanding of the hydroentangling mechanism. We have successfully visualized and analyzed structures of entangled regions through 2D and 3D imaging techniques. The influence of water-jet pressure, jet diameter, and number of jets on hydroentangled web structures is reported.}, number={4}, journal={The Journal of The Textile Institute}, publisher={Informa UK Limited}, author={Suragani Venu, Lalith B. and Shim, Eunkyoung and Anantharamaiah, Nagendra and Pourdeyhimi, Behnam}, year={2013}, month={Sep}, pages={430–443} }
@article{kilic_shim_yeom_pourdeyhimi_2013, title={Improving electret properties of PP filaments with barium titanate}, volume={71}, ISSN={["0304-3886"]}, DOI={10.1016/j.elstat.2012.11.005}, abstractNote={Barium titanate (BaTiO3) containing polypropylene (PP) composite filaments 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. It was found that both BaTiO3 concentration and charging temperature influence the charging characteristics of the fibers. When BaTiO3/PP composite filaments were charged at 130 °C, significant enhancements were observed when compared to samples charged at room temperature. The distribution of BaTiO3 particles within the filaments and changes in the crystal structure were also examined.}, number={1}, journal={JOURNAL OF ELECTROSTATICS}, publisher={Elsevier BV}, author={Kilic, Ali and Shim, Eunkyoung and Yeom, Bong Yeol and Pourdeyhimi, Behnam}, year={2013}, month={Feb}, pages={41–47} }
@article{datla_shim_pourdeyhimi_2012, title={Surface modifications of polypropylene with nonylphenol ethoxylates melt additives}, volume={52}, ISSN={["1548-2634"]}, DOI={10.1002/pen.23153}, abstractNote={AbstractNonylphenol ethoxylated (NPE) additives were melt blended in polypropylene (PP) films and characteristics of the modified films were investigated. It was found that melt blending of NPE additives improved hydrophilicity of PP films through additive surface segregation. Surface specific techniques, such as X‐ray photoelectron spectroscopy (XPS) and Time‐of‐Flight Secondary Ion Mass Spectrometry (ToF‐SIMS) were used to study surface compositions of samples modified with NPE additives at different aging time after extrusion. We found that surface enrichment of additives lead to hydrophilic surfaces. Hydrophilic chain length in NPE affected surface composition and hydrophilicity of NPE containing PP polymer. The effect of water immersion and aging were also reported. POLYM. ENG. SCI., 52:1920–1927, 2012. © 2012 Society of Plastics Engineers}, number={9}, journal={POLYMER ENGINEERING AND SCIENCE}, author={Datla, V. and Shim, E. and Pourdeyhimi, B.}, year={2012}, month={Sep}, pages={1920–1927} }
@article{venu_shim_anantharamaiah_pourdeyhimi_2012, title={Three-Dimensional Structural Characterization of Nonwoven Fabrics}, volume={18}, ISSN={["1435-8115"]}, DOI={10.1017/s143192761201375x}, abstractNote={AbstractNonwoven materials are found in a gamut of critical applications. This is partly due to the fact that these structures can be produced at high speed and engineered to deliver unique functionality at low cost. The behavior of these materials is highly dependent on alignment of fibers within the structure. The ability to characterize and also to control the structure is important, but very challenging due to the complex nature of the structures. Thus, to date, focus has been placed mainly on two-dimensional analysis techniques for describing the behavior of nonwovens. This article demonstrates the utility of three-dimensional (3D) digital volumetric imaging technique for visualizing and characterizing a complex 3D class of nonwoven structures produced by hydroentanglement.}, number={6}, journal={MICROSCOPY AND MICROANALYSIS}, publisher={Cambridge University Press (CUP)}, author={Venu, Lalith B. Suragani and Shim, Eunkyoung and Anantharamaiah, Nagendra and Pourdeyhimi, Behnam}, year={2012}, month={Dec}, pages={1368–1379} }
@article{datla_shim_pourdeyhimi_2011, title={Polypropylene Surface Modification with Stearyl Alcohol Ethoxylates to Enhance Wettability}, volume={121}, ISSN={["0021-8995"]}, DOI={10.1002/app.31051}, abstractNote={AbstractStearyl alcohol ethoxylated additives were melt‐blended in polypropylene (PP) films, and the characteristics of the modified films were investigated. The melt blending of stearyl alcohol ethoxylates improved the hydrophilicity of the PP films through additive surface segregation. Surface specific techniques, such as X‐ray photoelectron spectroscopy and time‐of‐flight secondary‐ion mass spectrometry, were used to study the surface compositions of the samples modified with ethoxylated additives. This revealed that the surface concentrations of the additives were significantly higher than the bulk concentrations in all samples. In addition, the surface compositions of the additive‐modified samples continuously changed, even after the films were fully solidified. We also found that the resulting surface characteristics were very dynamic, so the melt‐additive‐containing polymer surfaces responded to water exposure, and their surface properties and morphologies were altered as a result. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011}, number={3}, journal={JOURNAL OF APPLIED POLYMER SCIENCE}, publisher={Wiley-Blackwell}, author={Datla, Vasantha M. and Shim, Eunkyoung and Pourdeyhimi, Behnam}, year={2011}, month={Aug}, pages={1335–1347} }
@article{rangasamy_shim_pourdeyhimi_2011, title={Structure and Tensile Properties of Nanoclay-Polypropylene Fibers Produced by Melt Spinning}, volume={121}, ISSN={["0021-8995"]}, DOI={10.1002/app.33619}, abstractNote={AbstractNanocomposite fibers of polypropylene and montmorillonite‐based organoclay were produced by a melt‐spinning process, and their structures and mechanical properties were studied. The addition of nanoclay in polypropylene increased the rate of crystallization and altered the microstructures of the fibers. Increases in the crystal size and a reduction in the molecular orientation were observed in the nanoclay–polypropylene composite fibers. The tensile properties of nanoclay composite fibers were also studied, and decreases in the fiber modulus and tenacity and increases in the strain at break were observed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011}, number={1}, journal={JOURNAL OF APPLIED POLYMER SCIENCE}, publisher={Wiley-Blackwell}, author={Rangasamy, Loganathan and Shim, Eunkyoung and Pourdeyhimi, Behnam}, year={2011}, month={Jul}, pages={410–419} }
@article{yeom_shim_pourdeyhimi_2010, title={Boehmite nanoparticles incorporated electrospun nylon-6 nanofiber web for new electret filter media}, volume={18}, ISSN={["1598-5032"]}, DOI={10.1007/s13233-010-0910-5}, number={9}, journal={MACROMOLECULAR RESEARCH}, publisher={Springer Science \mathplus Business Media}, author={Yeom, Bong Yeol and Shim, Eunkyoung and Pourdeyhimi, Behnam}, year={2010}, month={Sep}, pages={884–890} }
@inproceedings{mukherjee_shim_mukundan_borup_2010, title={Digital Volume Imaging of the PEFC Gas Diffusion Layer}, DOI={10.1149/1.3484641}, abstractNote={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 GDL microstructure. The internal pore structure and the local microstructural variations in terms of fiber alignment and fiber/binder distributions are investigated using the several 3-D thin sections of the sample obtained from DVI.}, publisher={The Electrochemical Society}, author={Mukherjee, Partha P. and Shim, Eunkyoung and Mukundan, Rangachary and Borup, Rodney L.}, year={2010} }
@article{datla_beck_shim_pourdeyhimi_2010, title={Reverse Phase HPLC Analysis of Commercial Surfactants used as Melt Additives}, volume={47}, ISSN={["0932-3414"]}, DOI={10.3139/113.110063}, abstractNote={Abstract
Reverse phase HPLC (High Performance Liquid Chromatography) was used to analyze the length distribution of polyoxyethylene (POE) chains in commercial surfactants that can be used as melt additives for hydrophilic polypropylene surface modification. Ten nonionic surfactants including ethoxylated alcohols, nonyl phenols and amines, PEG esters, and mono glycerides were investigated. HPLC methods described herein are capable of analyzing ethoxylated nonionic surfactants and offer the advantage of separating the components in surfactants according to both the hydrophobe and hydrophile chain length. Moreover, the method is rapid and gradient elution allows for good baseline separation of the several components in the additives.}, number={3}, journal={TENSIDE SURFACTANTS DETERGENTS}, author={Datla, V. M. and Beck, K. and Shim, E. and Pourdeyhimi, B.}, year={2010}, pages={142–150} }
@article{shim_pourdeyhimi_latifi_2010, title={Three-dimensional analysis of segmented pie bicomponent nonwovens}, volume={101}, ISSN={["1754-2340"]}, DOI={10.1080/00405000903357938}, abstractNote={Three‐dimensional structural analysis utilizing digital volumetric imaging is used to fully understand the splitting of bicomponent fibers by hydroentangling. It was found that lower fabric density measured by solid volume fraction, higher degree of splitting and a higher thickness fiber orientation direction was evident at the jet streak valley position. Splitting was found to be more dominant on the surface of the fabrics. Washing the fabric increased fiber splitting and also resulted in more uniform splitting, but did not result in any significant change in local fiber orientation, that is, the structure.}, number={9}, journal={JOURNAL OF THE TEXTILE INSTITUTE}, author={Shim, E. and Pourdeyhimi, B. and Latifi, M.}, year={2010}, pages={773–787} }
@article{jaganathan_tafreshi_shim_pourdeyhimi_2009, title={A study on compression-induced morphological changes of nonwoven fibrous materials}, volume={337}, ISSN={["1873-4359"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-59349102148&partnerID=MN8TOARS}, DOI={10.1016/j.colsurfa.2008.12.019}, abstractNote={Pore size is a characteristic parameter that is often defined for fibrous materials used in industrial applications. While there exist many available studies on the pore size distribution of different fibrous materials, the influence of compression load on pore size distribution has not been studied well. Studying the behavior of fibrous materials under compression is important especially because in many applications these materials are subjected to some degree of compression during use. In this work, we present a novel image-based modeling technique to study the changes in the pore size distribution of a fibrous material exposed to compressive load. This was made possible by building a miniature compression cell, and imaging the structure of a hydroentangled fabric under varying levels of compression. The 3D images obtained with Digital Volumetric Imaging were utilized to study the pore size distribution of the material and develop an empirical correlation as a function of compressive stress for these structures. This new correlation indicates that the mean pore diameter of a nonwoven material decreases exponentially with increasing the compressive stress.}, number={1-3}, journal={COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS}, author={Jaganathan, S. and Tafreshi, H. Vahedi and Shim, E. and Pourdeyhimi, B.}, year={2009}, month={Apr}, pages={173–179} }
@article{shim_park_srinivasarao_2008, title={Forced coating of polypropylene fibers with non-wetting fluids: The scaling of the film thickness}, volume={22}, ISSN={["0217-9849"]}, DOI={10.1142/s0217984908016649}, abstractNote={ The film thickness of free-meniscus coating of a polymeric fiber with a non-wetting fluid was investigated. A polypropylene monofilament fiber was coated with various glycerol/water mixtures. With a small capillary number (Ca), a detectable liquid film did not form on the fiber due to the non-wettability of the fiber-liquid system. Above a certain threshold velocity, liquid was forced to wet the fiber by hydrodynamic forces, thus forming a film. However, the film thickness in this region is lower than Landau–Levich–Derjaguin (LLD) theoretical value for the wetting system. At a moderate velocity range, the film thickness increases to a value predicted either by the LLD law or White–Tallmadge (WT) model, depending on the velocity, mimicking that of the wetting system. At a higher Ca, the film thickness increases much more rapidly, deviating from any predictions, due to the inertial effect. }, number={22}, journal={MODERN PHYSICS LETTERS B}, author={Shim, E. and Park, Jung Ok and Srinivasarao, Mohan}, year={2008}, month={Aug}, pages={2043–2053} }
@article{verenich_arumugam_shim_pourdeyhimi_2008, title={Treatment of raw cotton fibers with cellulases for nonwoven fabrics}, volume={78}, ISSN={["1746-7748"]}, DOI={10.1177/0040517507083308}, abstractNote={ Enzymatic treatment of fabrics is known to have a negative impact on the fabrics' tensile characteristics. The strength loss problems would be more severe in the case of nonwovens, since cellulase could attack bonded areas of the fabric. To prevent the fabric strength loss, a study was undertaken to treat cotton fibers as opposed to the final fabric. Raw cotton fibers were hydrolyzed with Cellusoft L and endoglucanase without a cellulose— binding domain. Factors such as the reducing end group, fiber length and tenacity were followed throughout the enzymatic hydrolysis. The results showed that if the concentration of Cellusoft L cellulase mixture was minimized to 0.25 % owf, extensive weakening of cotton fibers could be prevented. Endoglucanase demonstrated a moderate reduction in fiber strength; most of the reduction occurred at the beginning of hydrolysis. The concentration of reducing ends was observed to have a maximum for both enzyme solutions. The location of enzymatic attack and changes in surface morphology were monitored by Congo red staining and scanning electron microscope, respectively. }, number={6}, journal={TEXTILE RESEARCH JOURNAL}, author={Verenich, Svetlana and Arumugam, Karthik and Shim, Eunkyoung and Pourdeyhimi, Behnam}, year={2008}, month={Jun}, pages={540–548} }
@article{verenich_arumugam_shim_pourdeyhimi_2007, title={Effect of cellulase pretreatment of raw and bleached cotton fibers on properties of hydroentangled nonwoven fabrics}, volume={105}, ISSN={0021-8995 1097-4628}, url={http://dx.doi.org/10.1002/app.26158}, DOI={10.1002/app.26158}, abstractNote={AbstractThis study was undertaken to investigate the effect of enzymatic pretreatment of cotton (polysaccharides) fibers on the properties of resulting nonwoven fabric. Enzymatic treatment is known to improve the esthetical properties of fabrics but will likely lead to a reduction in strength. In the case of nonwovens the strength loss can be even more drastic as cellulase may attack bonded areas of the fabric. In this work, raw and bleached cotton fibers were treated with enzyme solutions prior to fabric formation to avoid possible damage to the bonded areas and improve strength retention. These fibers were first modified with commercially available whole cellulases and monocomponent endoglucanase enzyme solutions. Then they were formed into a fabric and bonded via hydroentangling. Parameters such as bending modulus, fabric tenacity, fiber strength, length and reducing power were measured for each sample. The pretreatment of cotton fibers prior to fabric formation showed that the resulting nonwovens could be stronger and more drapeable than the same fabric composed of untreated fibers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007}, number={2}, journal={Journal of Applied Polymer Science}, publisher={Wiley}, author={Verenich, S. and Arumugam, K. and Shim, E. and Pourdeyhimi, B.}, year={2007}, pages={492–499} }
@article{arumugam_verenich_shim_pourdeyhimi_2007, title={Pretreatment of bleached cotton fibers with whole and Monocomponent cellulases for nonwoven applications}, volume={77}, DOI={10.1177/0040517507078807}, abstractNote={ Enzymatic treatment of fabrics has been carried out in the past to enhance the aesthetic properties, which has often resulted in the reduction of fabric strength. The objective of the current investigation was to develop process recipes for the production of soft and strong nonwoven fabric from enzymatically treated cotton fibers. Two different enzymatic solutions, the whole cellulase and Cellulose Binding Domain (CBD)-free monocomponent endoglucanase, were selected for this purpose. The latter was used as potential enzyme solution that could reduce the fiber strength loss during hydrolysis. This paper discusses the changes in reducing power, protein adsorption, surface properties and single fiber tenacity of bleached cotton fibers and compares with those obtained with raw cotton treated at identical conditions. The results observed in this study showed that bleached cotton was less susceptible to damage and weakening than raw cotton fibers. Thus, the aggressive whole cellulase is more suitable for treatment of bleached cotton fibers, whereas CBDfree endoglucanase is sufficient for treatment of raw cotton fibers. }, number={10}, journal={Textile Research Journal}, author={Arumugam, K. and Verenich, S. and Shim, Eunkyoung and Pourdeyhimi, B.}, year={2007}, pages={734–742} }
@article{shim_pourdeyhimi_2006, title={Hydroentangling knitted fabrics for improving abrasion resistance}, volume={97}, ISSN={["0040-5000"]}, DOI={10.1533/joti.2006.0268}, abstractNote={Abstract Hydroentangling is used as the mechanical finish to improve abrasion resistance of knitted fabrics. The hydroentangling process successfully reduced the amount of loose surface fibers and led to improved abrasion resistance. However, other properties such as fabric thickness and softness were also affected by the treatment.}, number={5}, journal={JOURNAL OF THE TEXTILE INSTITUTE}, author={Shim, E. and Pourdeyhimi, B.}, year={2006}, pages={435–440} }
@article{shim_pourdeyhimi_2005, title={A note on jet streaks in hydroentangled nonwovens}, volume={75}, ISSN={["0040-5175"]}, DOI={10.1177/0040517505053955}, abstractNote={ Hydroentanglement is the fastest growing bonding method in the nonwoven arena. Its strengths are good fabric aesthetics, and the lack of any complex binder chemistry with its inherent environmental concerns. Hydroentanglement is used for mechanically bonding both staple and filament nonwovens as well as being used for post-treatment of fabrics. As hydroentangling uses fine, closely spaced, high-speed waterjets, they create ridges or streaks that are quite visible to the naked eye. This may be undesirable if it interferes with other textures on the surface or if a smooth flat surface is desired. This study reports on methodology used for the analysis of jet streaks using texture-based methods. }, number={7}, journal={TEXTILE RESEARCH JOURNAL}, author={Shim, E and Pourdeyhimi, B}, year={2005}, month={Jul}, pages={569–577} }
@article{shim_pourdeyhimi_little_2004, title={Luminescence and mechanical properties of photoluminescent core bicomponent fibers}, volume={74}, ISSN={["0040-5175"]}, DOI={10.1177/004051750407401108}, abstractNote={ Photoluminescent fibers with a sheath-core morphology are produced to impart good mechanical properties. Both photoluminescent and mechanical properties are examined for these fibers with respect to photoluminescent pigment concentrations in the core, draw ratios, and polymer types. The photoluminescent pigment concentration in the core of the fibers directly influences their luminance intensity and afterglow properties as well as their mechanical properties. }, number={11}, journal={TEXTILE RESEARCH JOURNAL}, author={Shim, E and Pourdeyhimi, B and Little, TJ}, year={2004}, month={Nov}, pages={982–988} }