Solvent Washing Dry Method for Aqueous Tape Casting

Yoon, Seok-Jin,Shin, Hyo-Soon,Park, Ji-Won,Kang, Chong-Yun,Kim, Tae-Song,Kim, Hyun-Jai The Korean Ceramic Society 2001 The Korean journal of ceramics Vol.7 No.2

For the fast dry of the aqueous tape, the process which water was replaced by organic solvent was proposed. Socalled, it was the solvent washing dry. Three organic solvents (methanol, ethanol and acetone) were selected for the washing solvent. The weight loss of the washed tapes was measured to evaluate the dry rate of the tapes and dried tapes were examined the generation of the cracks with the variations of the organic solvent and the washing time. Methanol, ethanol and acetone were available organic solvents for this method. The tapes washed in methanol, ethanol and acetone were dried rapidly for twenty minutes. After thirty minutes, the weight losses were not found any more. The solvent of the lower surface tension can decreases the crack of dried tape. If solvent substitutes water completely, though it was fast dried, crack can be eliminated.

Study of solvent casting/particulate leaching technique membranes in pervaporation for dehydration of caprolactam

Wenhai Lin,Qin Li,Tianrong Zhu 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.3

New porous and rough PVA (polyvinyl alcohol) membranes were synthesized by solvent casting/particulate leaching technique to improve caprolactam (CPL) pervaporation (PV) separation dehydration process. The membranes were characterized by FTIR, SEM, XRD, and contact angle measurements. On account of their special structure, solvent casting/particulate leaching technique membranes showed different surface morphologies compared with the original PVA membrane with enhanced hydrophilicity. By evaluating PV performance and mechanism, a PV transport equation was introduced to evaluate composite membrane permeation flux, separation factor, diffusivity/sorptivity selectivity,and activation energy. The maximum flux obtained in this work was greatly improved to 3.2 kg/m2 h and reached industrial application levels for separating CPL/water mixtures (CPL 70 wt%).

Fabrication of solid oxide fuel cells (SOFCs) by solvent-controlled co-tape casting technique

Lee, S.,Lee, K.,Jang, Y.h.,Bae, J. Pergamon Press ; Elsevier Science Ltd 2017 International journal of hydrogen energy Vol.42 No.3

<P>A co-tape casting process has an advantage of cost-effectiveness for mass production. To fabricate solid oxide fuel cells (SOFCs) with high electrochemical performance by co-tape casting, high solid loading and binder content of tape cast slurry are required to improve particle network strength. However, high solid loading and binder content cause high viscosity of the slurry, which makes removal of air bubbles and handling difficult. In this study, a new method to fabricate uniform green tapes with high solid loading and binder content by controlling solvent ratio under vacuum condition is proposed. As a result, high solid loading and binder content with 39% improved storage shear modulus, 26% improved LVR length, tensile strength of 5.0 MPa, and packing density of 57.5% were achieved at solvent ratio of 22 wt%. To fabricate unit cells using the green tapes, thermal decomposition and shrinkage behavior are characterized, and heat treatment steps at 250 degrees C, 350 degrees C, and 500 degrees C and co-sintering temperature were determined at 1250 degrees C. A fabricated unit cell showed open circuit voltage (OCV) of 1.10 V and the maximum power density of 1.20 W cm(-2) at 800 degrees C. To fabricate crack-free Phi 5.0 cm unit cells, the mechanical strength of the anode support tapes after thermal decomposition was measured to determine the tape compositions that can minimize cracks at the unit cell. As a result, a crack-free unit cell with a diameter of 5.0 cm was fabricated, achieving OCV of 1.05 V and power of 4.3 W at 800 degrees C. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.</P>

Effects of Preparation Method on Properties of Poly(butylene adipate-co-terephthalate) Films

Gaobin Li,Shiv Shankar,임종환,오봉윤 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.5

Poly(butylene adipate-co-terephthalate) (PBAT) films were prepared using 4 different preparation methods and the effects of the processing method on physical, mechanical, and structural properties of PBAT films were studied. Films were characterized using UV-visible spectroscopy, FT-IR, XRD, and thermogravimetric analysis. All films were white in color and exhibited high UV-barrier properties. Films prepared using solvent casting (SC) were less transparent than other films. No structural changed were observed among PBAT films but films prepared at high temperatures exhibited a higher degree of crystallinity. Extrusion-cast (EC) films exhibited highest tensile strength values, while solvent-cast (SC) films had the lowest TS values. The water vapor permeability and water contact angle were not affected by the processing method. The degree of crystallinity of EC films was higher than for other films.

탈미네랄화된 골분용액을 함침시킨 PLGA 지지체의 제조 및 특성

백미옥 ( Mi Ock Baek ),김순희 ( Soon Hee Kim ),소정원 ( Jung Won So ),임지예 ( Ji Ye Lim ),최진희 ( Jin Hee Choi ),이종문 ( John M. Rhee ),이해방 ( Hai Bang Lee ),강길선 ( Gilson Khang ) 한국조직공학·재생의학회 2008 조직공학과 재생의학 Vol.5 No.2

We developed the synthetic/natural hybrid scaffolds with poly (lactide-co-glycolide)(PLGA) and solution using DBP(DB solution) for tissue engineering. Composite scaffolds of PLGA scaffold penetrated DB solution (PLGA-pen-DBP) were manufactured by simple method that PLGA scaffolds manufactured by solvent casting/salt leaching method soaked in DB solution. We evaluated pore structure, wettability, water uptake ability and cell viability of two types of scaffolds. Through SEM and FT-IR, it was confirmed that DB solution was put into the pores of PLGA scaffold. Also, the effects of the impregnation of DB solution on PLGA scaffolds were characterized through water uptake ability and cell viability. It seemed that DBP provided proper pore to PLGA scaffold and improved water absorption. A novel scaffold, which PLGA scaffold penetrated with DB solution, might be suitable to apply as tissue engineered scaffold.

Rapid recycling of waste salt core materials in foundry industry using fractional crystallization

Xiaolong Gong,Xiongjie Xiao,Qianqian Li,Jianwei Zhao,Zitian Fan 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.124 No.-

The water-soluble composite salt core materials have attracted increasing interest in the manufacture ofhollow castings with complex structures due to their high strength and excellent water solubility, whilethe treatment of waste brine generated from the salt core represents a major pain point for its large-scaleapplication. To change the above situation, the recycling technology of the waste brine from compositesalt core materials was developed using cooling crystallization combined with solvent-driven crystallization. The influences of dissolution temperature and solvent content on the recovery rate of the compositesalt core materials, including inorganic salt and fortifier, were investigated. In addition, the mechanicalproperties and microstructures of the composite salt core with multiple cycles were compared and analyzed. The results show that the fortifier material of corundum powder exhibits excellent chemical andthermal stability with a 100% recovery rate, and the recovery rate of inorganic salt material can reach79.31% with a 40 C dissolution temperature and a 1.0 mass ratio of methanol to brine. The microstructures,phase compositions and mechanical properties of the multi-recycled composite salt core have notchanged, demonstrating that the recycling of the water-soluble composite salt core is feasible, and favoringthe green development of the foundry industry.

직접 메탄올 연료전지용 술폰화 폴리아릴에테르술폰 전해질 막의 혼합 캐스팅 용매에 따른 형태 및 특성

홍영택,박지영,최준규,최국종,황택성,김형중 한국막학회 2008 멤브레인 Vol.18 No.4

친전자성 치환반응으로 제조된 술폰화 단량체, 비(非)술폰화 단량체 및 탄산칼륨을 이용하는 직접 중합법을 통하여 높은 점도의 술폰화 폴리아릴에테르술폰 공중합체를 합성하고, 이들을 원료로 N-메틸-2-피롤리돈(NMP)과 디메틸아세트아미드(DMAc)의 혼합 용매 상에서 직접 메탄을 연료전지용 고분자 전해질 막을 제조하였다. 막 제조 시의 용매 효과에 주목하여 혼합 용매의 부피 비는 0~100%로 변화시키고 공중합체의 술폰화도는 50%로 고정하였다. 이온 전도도 및 메탄올 투과도 측정을 통하여 최종 전해질 막의 기본 특성을 파악하고, 주사전자현미경 및 원자간력현미경분석을 통한 표면 분석 결과와 비교함으로써 이들의 상관관계를 고찰하였다. 막 제조 시의 용매 혼합 비율을 적절히 조절함에 따라 최종 전해질 막의 이온 전도도를 크게 향상시킬 수 있음이 확인되었는데, 25℃의 100% 가습 환경에서 측정된 수소 이온 전도도는 NMP : DMAc 50:50 부피/부피-%에서 최대 1.38x10 -1 S/cm이었다. Partially sulfonated poly(aryl ether sulfone) membranes were prepared from the sulfonated sulfone monomer, which was synthesized by a nucleophilic substitution, non-sulfonated monomers and potassium carbonate by a direct polymerization method and a subsequent solution casting technique with mixed solvents of N-methyl-2-pyrrolidone (NMP) and dimethylacetamide (DMAc). To investigate the effect of mixed solvent, the volume ratios of NMP and DMAc were varied in the range of 0~100% and the degrees of sulfonation of the copolymers were fixed as 50%. The surface properties of the resulting membranes were examined by scanning electron microscope (SEM) and atomic force microscope (AFM), and a comparative study of the morphology changes and the physicochemical properties such as proton conductivity and methanol permeability was achieved. It was found that proton conductivities depend on the volume ratio of NMP-DMAc mixed solvents, and the proton conductivity determined at the condition of 25℃ and 100% relative humidity was 1.38x10 -1 S/cm for the membrane prepared in the 50:50 v/v-% of NMP : DMAc mixed solvent.

Solvent casting effects of sulfonated poly(ether ether ketone) for Polymer electrolyte membrane fuel cell

Jun, M.S.,Choi, Y.W.,Kim, J.D. Elsevier Scientific Pub. Co 2012 Journal of membrane science Vol.396 No.-

The properties of sulfonated poly(ether ether ketone) (SPEEK) were investigated by various solvents such as N-methly-2-pyrrolidone (NMP), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), and dimethylformamide (DMF). The SPEEK membranes were activated by the solution of 1M H<SUB>2</SUB>SO<SUB>4</SUB> to remove the remaining solvents in the membranes. The properties of proton conductivity and cell performance of the membranes after activated treatment were improved compared to those of before activated treatment. Especially, the proton conductivity and cell performance of the SPEEK membrane using NMP as a solvent was the equal to that of the Nafion 117 membrane. We suggest that the selection of a casting solvent and membrane activation treatment for removing of the remaining solvent in the membrane can be a very important factor to get a high performance membrane.

Solvent Vapor Annealing Effects in Contact Resistances of Zone-cast Benzothienobenzothiophene (C₈-BTBT) Transistors

Kim, Chaewon,Jo, Anjae,Kim, Heeju,Kim, Miso,Lee, Jaegab,Lee, Mi Jung The Korean Ceramic Society 2016 한국세라믹학회지 Vol.53 No.4

Benzothienobenzothiophene ($C_8-BTBT$) is a soluble organic small molecule material with high crystallinity resulting from its strong self-organizing properties. In addition, the high mobility and easy fabrication of $C_8-BTBT$ make it very attractive in terms of organic thin-film transistors. In this work, we made $C_8-BTBT$ thin films by using the zone-casting method; we also used an organic solvent to treat the devices with solvent vapor annealing to improve the electrical properties. As a result, we confirmed improved mobility, threshold voltage, and subthreshold swing after solvent vapor annealing. To prove the effect of solvent vapor annealing, we used the simultaneous extraction model to extract the contact resistance from the current-voltage curve. We confirmed that the electrical properties improved with decreasing contact resistance.

용액 코팅법을 통한 연료전지용 불소계 전해질 강화복합막의 특성에 미치는 분산용매의 영향

육승호,윤기로,최지훈,이주성,김종민,이승우,이관영,김진영 한국화학공학회 2019 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.57 No.3

the recent, as a world demand of energy resources has been transformed from fossil fuels to hydrogenbased clean energy resources, a huge attention has been attracted to increase the performance and decrease a production cost of core materials in fuel cell technology. The utilization of reinforced composite membranes as electrolytes in the polymer electrolyte membrane fuel cells can reduce the use of high cost perfluorosulfonic acid (PFSA), mitigate the cell impedance, and improve the dimensional stability as well as the interfacial stability, giving rise to achieve both an improved performance and a reduction of production costs of the fuel cell devices. In this study, we investigate the effects of physical characteristics and cell performances according to the various ionomer solvents in the solution based manufacturing process of reinforced composite electrolyte membrane. 최근 화석연료기반에서 친환경 수소 기반의 청정에너지원으로 전환되는 세계적 흐름에 따라, 수소연료전지의 고성능저가격 핵심 소재 기술 개발에 많은 관심이 이루어지고 있다. 그 가운데 연료전지의 전해질로 사용되는 강화복합막의기술 도입은 과불소계 술폰산 이오노머(Perfluorosulfonic acid, PFSA) 양의 감소 및 막 두께 감소를 통한 가격 저감 및셀 저항 감소, 치수 안정성 개선 그리고 계면 안정성에 대한 확보가 가능하여 최종적으로 연료전지 성능 향상과 가격절감이 동시에 가능하다. 본 연구에서는 연료전지용 불소계 전해질 강화복합막 코팅 공정에서 이오노머 분산용매에 따라 막 형성 및 물성 변화와 연료전지 성능에 미치는 영향에 대해 연구하였다.