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UV-curing kinetics and performance development of <i>in situ</i> curable 3D printing materials
Kim, Ye Chan,Hong, Sungyong,Sun, Hanna,Kim, Myeong Gi,Choi, Kisuk,Cho, Jungkeun,Choi, Hyouk Ryeol,Koo, Ja Choon,Moon, Hyungpil,Byun, Doyoung,Kim, Kwang J.,Suhr, Jonghwan,Kim, Soo Hyun,Nam, Jae-Do Elsevier 2017 European polymer journal Vol.93 No.-
<P><B>Abstract</B></P> <P>As three-dimensional (3D) printing technology is emerging as an alternative way of manufacturing, the high resolution 3D printing device often requires systems such as drop jetting printing of <I>in situ</I> UV-curable photopolymers. Accordingly, the key issue is process control and its optimization to ensure dimensional accuracy, surface roughness, building orientation, and mechanical properties of printed structures, which are based on the time- and temperature-dependent glass transition temperature (<I>T<SUB>g</SUB> </I>) of the resin system under UV-curing. In this study, the UV-cure kinetics and <I>T<SUB>g</SUB> </I> development of a commercially available UV-curable acrylic resin system were investigated as a model system, using a differential scanning photocalorimeter (DPC). The developed kinetic model included the limited conversion of cure that could be achieved as a maximum at a specific isothermal curing temperature. Using the developed model, the <I>T<SUB>g</SUB> </I> was successfully described by a modified DiBenedetto equation as a function of UV curing. The developed kinetic model and <I>T<SUB>g</SUB> </I> development can be used to determine the 3D printing operating conditions for the overlay printing and <I>in situ</I> UV curing, which could ensure high-resolution and high-speed manufacturing with various UV-curing materials.</P> <P><B>Highlights</B></P> <P> <UL> <LI> UV-cure kinetic analysis were applied to a commercial Multi-jet 3D printing material. </LI> <LI> The developed kinetic model included the limited conversion of cure by temperature. </LI> <LI> The <I>T<SUB>g</SUB> </I> was described by a modified DiBenedetto equation as a function of UV curing. </LI> <LI> The developed kinetic model showed an excellent agreement to isothermal experiments. </LI> <LI> The overlay printing time for each isothermal temperature was determined. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Comparison of UV-Curable Acrylic pressure-sensitive adhesive by acrylate monomers
석웅철,임종태,권세진,강주희,송호준,이상국 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0
The UV initiated crosslinking of acrylic pressure-sensitive adhesive (acrylic PSA) is one of the most rapidly developing fields in the entire coating and self-adhesive industry. Industrial applications of photoreactive acrylic PSA have grown tremendously over the past decade. UV technology is well established in the market and allows the production of a wide range of UV-crosslinking PSAs with interesting features. In this study, we conducted to comparison of acrylic PSA property according to acrylate monomers. UV-curable acrylic PSAs were fabricated through blending of pre-polymer and acrylate monomer. Pre-polymer was synthesized via free-radical polymerization. Synthesized pre-polymer was analyzed Fourier Transform Nuclear Magnetic Resonance (FT-NMR), Fourier Transform Infrared (FT-IR). Fabricated UV-curable acrylic PSAs was characterized by Gel Permeation Chromatography (GPC) and Contact Angle Analyzer.
UV-경화 폴리머 마이크로 구조물의 응력-변형률 관계 측정에 관한 연구
정수정(S. -J. Jeong),김재현(J. -H. Kim),이학주(H. -J. Lee),박상후(S. H. Park),양동열(D. -Y. Yang) 한국정밀공학회 2005 한국정밀공학회 학술발표대회 논문집 Vol.2005 No.10월
In this study, we propose an advanced nanoindentaion test, Nano Pillar Compression Test (NPCT) to measure a stress-strain relation for micro scale polymer structures. Firstly, FEM analysis is performed to research behavior of micro polymer pillars in several specimen aspect ratios and different friction conditions between specimen and tip. Based on the FEM results, micro scale UV-curable polymer pillars are fabricated on a substrate by Nano Stereo Lithography (NSL). To measure their mechanical properties, uniaxial compression test is performed using nanoindentation apparatus with flat-ended diamond tip. In addition, the dependency of compression properties on loading condition and specimen size are discussed.
도일,윤세찬,진영현,조영호 한국물리학회 2012 Current Applied Physics Vol.12 No.6
We present a rapid and low-temperature polymer fabrication method based on the direct patterning by UV light. Compared to the conventional polymer micromolding method for polydimethylsiloxane (PDMS) and cyclic olefin copolymers (COC), the present method has advantages of rapid fabrication in low-temperature environment. We used an AEO3000, UV-curable low-stress hyper-branched polymer (HBP), as a polymer material. The AEO3000 layer was selectively exposed to UV light by a photomask at room temperature for 3 min. Using the present method, we designed the rigid substrate for the microelectrofluidic bench. The measured electrical and fluidic interconnection characteristics in the bench were 0.75 ± 0.44 Ω and 8.3 kPa (at the flow rate of 100 ml/min), respectively. Both electric and fluidic characteristics were equivalent or lower than the sum of individual devices. We also successfully verified the bio-sample analysis through the interconnected devices on the microelectrofluidic bench using yeast cell samples. The proposed method offers fast and bio-compatible process applicable to biomedical micro total analysis systems.
Lee, Albert S.,Lee, Jin Hong,Choi, Seung-Sock,Cho, Kie Yong,Yu, Seunggun,Koo, Chong Min,Baek, Kyung-Youl,Hwang, Seung Sang Pergamon Press 2017 European polymer journal Vol.95 No.-
<P><B>Abstract</B></P> <P>A series of inorganic-organic hybrid UV-curable ionic polysilsesquioxanes were synthesized through Menshutkin reactions with various tertiary amine vinyl or methacrylic monomers to quantitatively quaternize various alkyl-halide ladder-like functionalized polysilsesquioxanes. The effect of quaternary ammonium salt cation, anion, as well as UV-curing were examined. Obtained ionic polysilsesquioxanes exhibited exceptional thermal stability (>350°C), high surface hardness (6H), high refractive index (>1.66), and substantial decrease in brittleness index. In addition to the excellent hardcoating properties, the ionic groups imbued antibacterial properties against gram positive and gram negative bacteria, which may allow for applications in flexible electronic devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A series of ionic group-functionalized hybrid copolymers were synthesized. </LI> <LI> UV-curing yielded mechanically robust ionic surfaces with optical transparency. </LI> <LI> Effect of cation and anion structure on antibacterial properties were investigated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
자외선 경화가능한 나노복합소재의 중합두께 예측모델 개발
임현철(Hyeoncheol Lim),최영(Young Choi),박상헌(Sangheon Park),황반토(Hoang Van Tho),윤상희(Sang-Hee Yoon) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12
Ultraviolet (UV) curable nanocomposites (NCs) are emerging as viable alternatives to thermal curable NCs in a variety of advanced engineering applications due to their fast polymerization. Despite extensive efforts, little is known about how to model the polymerized thickness of UV curable NCs especially when non-spherical nanofillers are embedded therein. Here, we develop a theoretical model for predicting the polymerized thickness of UV curable NCs by modifying the Beer-Lambert law to reflect both inter-nanofiller distance and nanofiller UV screening. The accuracy of the model is accessed by comparing its prediction with experimental data for graphite nanoflake (GnF)-embedded SU-8 composites having different GnF concentrations of 1 to 25 wt%. The findings of this study will lead to successful and growing development of UV curable NCs.
지르코니아 나노입자 기반 나노패턴 금속 몰드 제작과 열가소성 재료의 복제성형 응용
박세림,민경찬,장소원,하유진,김욱배 한국정밀공학회 2022 한국정밀공학회지 Vol.39 No.7
Fabrication of a durable and strong nanopatterned mold insert using metal sheet and plate is important for molding of thermoplastic materials. Conventionally, the nickel stamper replicating a master pattern by electroforming process hasbeen used for injection molding of nanotextured products such as Blu-ray media. However, a more facile and cheaper mold fabrication process is highly required for manufacturing of functional products based on nanostructured surface. In this study, zirconia nanoparticles were blended with UV curing polymer to fabricate a polymer nanocompositebased nanopattern mold. Compared to the cured pure Ormostamp, the modulus of elasticity of the nanocomposite filled with approximately 54 vol% of zirconia nanoparticles increased by 160 times. Additionally, the modulus of elasticity reached 197 GPa by thermal decomposition of the UV-Cured polymer and post-annealing at 800°C of the nanoparticle layer. The nanopatterns were formed on stainless steel sheet and block, and applied to hot embossing of the PMMA films and injection molding of the COC materials, respectively. No deterioration of the mold occurred during the hot embossing 30 times and the injection molding 600 shots. Nanoparticle-enhanced UV curing nanocomposites or post-heat treatment methods are cost-efficient and easy, because many molds can be manufactured from one master pattern.
민성준,김신웅,이태훈,손태일 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1
The aim of this study was to prepare derivatives in the form of injectables that can effectively deliver drugs. Azidophenyl hyaluronic acid derivatives were prepared using natural polymer hyaluronic acid with biocompatibility and biodegradability. It was confirmed that Az-Hyaluronic acid was prepared by FT-IR and 1H-NMR analysis. Photo-curing test was conducted to determine the degree of photocuring with ultraviolet light irradiation time and concentration. Protein immobilization test and protein release test were conducted to determine whether the drug was immobilized and released. Through cytotoxicity test, biocompatibility was confirmed. As a result of intracellular administration of Az-Hyaluronic acid derivatives immobilized with epidermal growth factor, cell proliferation was confirmed. According to the results, the prepared UV-curable Azidophenyl hyaluronic acid derivatives are considered to have an applicability as a medical material capable of effective drug delivery.