가지형 메탈옥사이드 나노파티클에 기반한 고분자 전해질 막

정정표,박정태,김진규,이정민,김종학 한국막학회 2015 한국막학회 총회 및 학술발표회 Vol.2015 No.05

TiO2 and SiO2 inorganic nanoparticles were synthesized with poly(oxyethylene methacrylate)(POEM) and blended with 1-methyl-3-propylimidazolium iodide(MPII), poly(ethylene glycol)(PEG), and iodine(I2) to prepare polymer electrolyte membranes for dye-sensitized solar cells(DSSC). The modified nanoparticles were prepared by the grafting of POEM to TiO2 and SiO2 nanoparticles and put into PEG, MPII and I2 to produce polymer electrolyte membranes. The specific interactions of PEG with the modified nanoparticles in addition to ionic liquid were confirmed by FT-IR spectroscopy and DSC, providing gel formation of electrolytes. The efficiency of DSSC employing TiO2-POEM/PEG/MPII/I2(3.3%) was slightly higher than that employing SiO2-POEM/PEG/MPII/I2(2.9%) due to the different ionic conductivity of electrolytes membrane.

Structural, Thermal, and Tribological Properties of Poly(vinylidene fluoride)/ Nano-TiO2 Composites Prepared by Dry-Mixing and Hot-Press Technique

정정표,김지수,한동석,김종학 한국고분자학회 2017 Macromolecular Research Vol.25 No.4

This paper describes the morphological, thermal, and tribological characteristics of poly(vinylidene fluoride) (PVDF)-based composites dispersed with nanosized TiO2 (nano-TiO2) particles. PVDF/nano-TiO2 composites with different nano-TiO2 loading (~40 wt%) were prepared via a dry-mixing and uniaxial hot-press molding technique. The incorporation of nano-TiO2 led to changes in the crystal structure of the PVDF, as characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. The uniform distribution and good interactions of the composites were confirmed by scanning electron microscopy and energy-dispersive spectrometry. The frictional performances increased with the amount of nano- TiO2 owing to the preferential formation of a nonpolar α-phase crystal and the reduced viscoelastic characteristics of the PVDF. The PVDF/nano-TiO2 composite with 30% loading exhibited the best frictional performance (a staticfriction coefficient of 0.23 and a kinetic-friction coefficient of 0.17), which is comparable to that of the composite prepared via a costly, environmentally unfriendly wet-mixing technique. Furthermore, the taber abrasion resistances were comparable to that of commercialized ultra-high-molecular-weight polyethylene (UHMWPE), indicating the effectiveness of PVDF/nano-TiO2 hybridization.

A facilitated olefin transport membrane based on PEMA-g-PPG graft copolymer and partially polarized silver nanoparticles

정정표,박민수,강동아,김종학 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

A low-cost, one-pot, room-temperature synthesized graft copolymer, i.e., poly(ethylene-alt-maleic anhydride)-g-O-(2-aminopropyl)-O′-(2-methoxyethyl) polypropylene glycol (PEMA-g-PPG) is reported for solid-state facilitated olefin transport membranes. The PEMA-g-PPG graft copolymer was synthesized via a facile one-pot polymerization at room temperature. PEMA-g-PPG works as an polymer matrix for partially polarized silver nanoparticles (AgNPs). As a precursor of AgNPs which can facilitate olefin transport through π-complexation, AgBF4 were added to the PEMA-g-PPG solution. TNCQ which is the strong electron acceptor was applied in the solution to activate surface of AgNPs for partial polarization. The FT-IR proved interactions between PEMA-g-PPG and AgNPs. The membrane with 1:3 wt ratio of PEMA-g-PPG:AgNPs showed the best propylene/propane separation performance. A mixed gas permeance and propylene/propane selectivity was a better than membranes based on commercial polymers.

증례 : Cryptococcal meningitis 의 1 예 (pp.658-663)

정정표 ( J. P. Chung ),박승국 ( S. K. Park ) 대한내과학회 1975 대한내과학회지 Vol.18 No.8

나노입자가 포함된 촉진수송 분리막에서의 메조기공 티타늄산화물의 영향

김상진,정정표,김동준,김종학 한국막학회 2015 멤브레인 Vol.25 No.5

용액-확산 메커니즘에 의해 결정되는 기존의 고분자에서와는 달리, 촉진수송은 투과도와 선택도를 동시에 향상시킬 수 있는 기술이다. 본 연구에서는 은 나노입자, 폴리비닐피롤리돈, 7,7,8,8-테트라시야노퀴노디메탄으로 구성된 촉진수송 올레핀 분리막에 있어서, 메조기공 티타늄산화물(m-TiO2)에 대한 영향을 연구하였다. 특히 메조기공 티타늄산화물은 폴리비닐클로라이 드-g-폴리옥시에틸렌 메타크릴레이트 가지형 공중합체를 템플레이트로 하여 쉽고 대량 생산이 가능한 방법으로 제조하였다. 엑 스레이 회절분석에 따르면, 제조된 메조기공 티타늄산화물은 아나타제와 루타일 상의 혼합으로 구성되어 있으며, 결정의 크기가 약 16 nm 정도 되었다. 메조기공 티타늄산화물을 첨가하였을 때, 분리막의 확산도가 증가하여 혼합기체 투과도가 1.6에서 16 GPU로 증가하였고 선택도는 45에서 37로 약간 감소하였다. 메조기공 티타늄산화물이 첨가되지 않은 분리막은 장시간 성능이 유지되었으나, 메조기공 티타늄산화물이 첨가된 분리막의 경우 시간이 지남에 따라 투과도와 선택도가 감소하였다. 이는 티타늄 산화물과 은 사이의 화학적 상호작용으로 은 나노입자의 올레핀 운반체로써의 활성을 감소시키기 때문으로 사료된다. Facilitated transport is considered to be a possible solution to simultaneously improve permeability and selectivity, which is challenging in normal polymeric membranes based on solution-diffusion transport only. We investigated the effect of adding mesoporous TiO2 (m-TiO2) upon the separation performance of facilitated olefin transport membranes comprising poly(vinyl pyrrolidone), Ag nanoparticles, and 7,7,8,8-tetracyanoquinodimethane as the polymer matrix, olefin carrier, and electron acceptor, respectively. In particular, m-TiO2 was prepared by means of a facile, mass-producible method using poly(vinyl chloride)-g-poly(oxyethylene methacrylate) graft copolymer as the template. The crystal phase of m-TiO2 consisted of an anatase/rutile mixture, of crystallite size approximately 16 nm as determined by X-ray diffraction. The introduction of m-TiO2 increased the membrane diffusivity, thereby increasing the mixed-gas permeance from 1.6 to 16.0 GPU (1 GPU = 10-6 cm3(STP)/(s × cm2 × cmHg), and slightly decreased the propylene/propane selectivity from 45 to 37. However, both the mixed-gas permeance and selectivity of the membrane containing m-TiO2 rapidly decreased over time, whereas the membrane without m-TiO2 had more stable long-term performance. This difference might be attributed to specific chemical interactions between TiO2 and Ag nanoparticles, causing Ag to lose activity as an olefin carrier.

상온에서의 단일 용기 내 공정을 통한 PEMA-g-PPG 가지형 공중합체 기반의 CO2 분리막 제조

김나운,정정표,박민수,김종학 한국막학회 2017 한국막학회 총회 및 학술발표회 Vol.2017 No.05

The CO2 separation membranes based on a graft copolymer consisting of hydrophobic poly(ethylene-alt-maleic anhydride) (PEMA) backbone and hydrophilic poly(propylene glycol) PPG side chains were fabricated by a facile one-pot process. The reaction between O-(2-aminopropyl)-O’-(2-methoxyethyl) polypropylene glycol (AMPPG) and PEMA was conducted in butanol at room-temperature. Without any post-treatment, the as-synthesized PEMA-g-PPG solution could be directly coated onto a microporous polysulfone support to fabricate thin-film composite membranes. The PEMA-g-PPG membrane exhibited high selectivity (82.6 for CO2/N2 and 26.8 for CO2/CH4) and good CO2 permeability (99.1 Barrer), which is a close value to the upper boundary limit (2008). The PEMA-g-PPG membrane could be commercially feasible owing to simple, inexpensive and scalable process.

CO2/N2 분리를 위한 무기 첨가제 혼합 블록 공중합체 분리막 제조

강동아,정정표,김종학 한국막학회 2018 한국막학회 총회 및 학술발표회 Vol.2018 No.11

An organic filler, bis-(N-α-amido-3,4-dihydroxyphenylalanine)-1,7-heptane dicarboxylate (DOPA-C7) is applied to gas separation membranes for CO2/N2 separation. The weak interaction between SBS and DOPA-C7 improves CO2/N2 selectivity, from 14.1 to 21.1 with increasing of CO2 permeability from 347.5 to 349.7 Barrer. This phenomenon is caused by the catechol group of DOPA-C7 that can work as a Lewis Base. However, the strongly interacting PEBAX/DOPA-C7 membranes show a typical trade-off behavior, a decrease in CO2 permeability and increase in CO2/N2 selectivity with the filler contents. This results demonstrate that interactions between the filler and polymeric matrix can cause negative effects on the gas separation performance. This work opens up the feasibility of using a catecholic compound in gas separation membranes.

Effect of Mesoporous TiO₂ in Facilitated Olefin Transport Membranes Containing Ag Nanoparticles

김상진,정정표,김동준,김종학,Kim, Sang Jin,Jung, Jung Pyu,Kim, Dong Jun,Kim, Jong Hak The Membrane Society of Korea 2015 멤브레인 Vol.25 No.5

용액-확산 메커니즘에 의해 결정되는 기존의 고분자에서와는 달리, 촉진수송은 투과도와 선택도를 동시에 향상시킬 수 있는 기술이다. 본 연구에서는 은 나노입자, 폴리비닐피롤리돈, 7,7,8,8-테트라시야노퀴노디메탄으로 구성된 촉진수송 올레핀 분리막에 있어서, 메조기공 티타늄산화물($m-TiO_2$)에 대한 영향을 연구하였다. 특히 메조기공 티타늄산화물은 폴리비닐클로라이드-g-폴리옥시에틸렌 메타크릴레이트 가지형 공중합체를 템플레이트로 하여 쉽고 대량 생산이 가능한 방법으로 제조하였다. 엑스레이 회절분석에 따르면, 제조된 메조기공 티타늄산화물은 아나타제와 루타일 상의 혼합으로 구성되어 있으며, 결정의 크기가 약 16 nm 정도 되었다. 메조기공 티타늄산화물을 첨가하였을 때, 분리막의 확산도가 증가하여 혼합기체 투과도가 1.6에서 16 GPU로 증가하였고 선택도는 45에서 37로 약간 감소하였다. 메조기공 티타늄산화물이 첨가되지 않은 분리막은 장시간 성능이 유지되었으나, 메조기공 티타늄산화물이 첨가된 분리막의 경우 시간이 지남에 따라 투과도와 선택도가 감소하였다. 이는 티타늄산화물과 은 사이의 화학적 상호작용으로 은 나노입자의 올레핀 운반체로써의 활성을 감소시키기 때문으로 사료된다. Facilitated transport is considered to be a possible solution to simultaneously improve permeability and selectivity, which is challenging in normal polymeric membranes based on solution-diffusion transport only. We investigated the effect of adding mesoporous $TiO_2$ ($m-TiO_2$) upon the separation performance of facilitated olefin transport membranes comprising poly(vinyl pyrrolidone), Ag nanoparticles, and 7,7,8,8-tetracyanoquinodimethane as the polymer matrix, olefin carrier, and electron acceptor, respectively. In particular, $m-TiO_2$ was prepared by means of a facile, mass-producible method using poly(vinyl chloride)-g-poly(oxyethylene methacrylate) graft copolymer as the template. The crystal phase of $m-TiO_2$ consisted of an anatase/rutile mixture, of crystallite size approximately 16 nm as determined by X-ray diffraction. The introduction of $m-TiO_2$ increased the membrane diffusivity, thereby increasing the mixed-gas permeance from 1.6 to 16.0 GPU ($1GPU=10^{-6}cm^3$(STP)/($s{\times}cm^2{\times}cmHg$), and slightly decreased the propylene/propane selectivity from 45 to 37. However, both the mixed-gas permeance and selectivity of the membrane containing $m-TiO_2$ rapidly decreased over time, whereas the membrane without $m-TiO_2$ had more stable long-term performance. This difference might be attributed to specific chemical interactions between $TiO_2$ and Ag nanoparticles, causing Ag to lose activity as an olefin carrier.

CaCO₃을 이용한 혼합매질분리막의 이산화탄소 투과도 향상

박철훈,정정표,이재훈,김종학,Park, Cheol Hun,Jung, Jung Pyo,Lee, Jae Hun,Kim, Jong Hak 한국막학회 2018 멤브레인 Vol.28 No.1

급진적인 산업발전에 따른 무분별한 이산화탄소 배출로 인하여 지구온난화, 이상 기후 등의 문제가 불거지고 있으며 이는 한 나라에만 국한되지 않은 국제적인 문제가 되었다. 위와 같은 문제를 해결하고자 본 연구에서는 이산화탄소에 대해 높은 친화도를 가지고 있는 PEGBEM-g-POEM 가지형 공중합체를 합성하였으며 $CaCO_3$염을 첨가하여 염의 중량에 따른 혼합매질분리막의 이산화탄소/질소 투과 성능을 관찰하였다. $CaCO_3$염이 고분자 중량 대비 50% 첨가되었을 때 최적의 이산화탄소/질소 분리 투과성능을 보였으며, 선택도는 염을 추가하기 전 44.7에서 45.42로 크게 변하지 않은 반면 이산화탄소 투과도는 염을 첨가하기 전 22.5 GPU에서 28.16 GPU로 약 25% 향상되었다. 이는 첨가한 염과 이산화탄소간의 상호작용으로 인하여 향상된 고분자 복합막의 이산화탄소에 대한 용해도에 기인하는 것으로 생각된다. 또한 염을 과량으로 첨가한 경우에는 고분자가 복합막의 표면을 충분히 메우지 못하여 계면결함이 생성되었으며 이로 인해 이산화탄소 기체 분리성능이 감소하였다. 기체분리성능 향상을 위해서는 적정량의 염 첨가가 필수적인 것으로 분석되었다. With vigorous development of petroleum and chemical industry, emission of carbon dioxide has attracted tremendous attention globally due to global warming problem and abnormal climate change. To address these problems, in this study, a PEGBEM-g-POEM graft copolymer with high $CO_2$ affinity was synthesized and $CaCO_3$ was incorporated to form mixed matrix membranes (MMMs) for enhancement of $CO_2$ permeance. By varying the addition weight of $CaCO_3$ in MMMs, high separation performance of $CO_2$ over $N_2$ was obtained. At 50 wt% loading of $CaCO_3$, the greatest separation performance was obtained with an enhanced $CO_2$ permeance from 22.5 to 28.16 GPU and slightly increased $CO_2/N_2$ selectivity from 44.7 to 45.42. It resulted from the increased $CO_2$ solubility of MMMs due to specific interaction between $CaCO_3$ and $CO_2$ molecules. Upon excess loading of $CaCO_3$, MMMs exhibited loss of $CO_2$ separation performance due to the formation of interfacial defects. Based on this result, it is considered that the proper addition of $CaCO_3$ is crucial for improvement of $CO_2$ separation performance.

NC 선반의 직선 사이클 평면 위치결정 정도 측정 및 분석

김영석,정정표,한지희,윤원주 朝鮮大學校 機械技術硏究所 2003 機械技術硏究 Vol.6 No.2

It is very important t o measure linear cycle plane positioning accuracy of NC lathes because the plane positioning accuracy affects accuracy, performance, interchange-ability and quality of machine parts machined by the NC lathes in industries. Until now, linear cycle plane positioning accuracy test of NC lathes has not been carried out because the two axes of NC lathe are moving simultaneously crossing a t right angle each other. while positioning accuracy test of one axis of NC lathe is briskly carried out using a laser interferometer system in industries. So, in this study, a measuring units system to measure simultaneously two axes' plane. positioning accuracy of NC lathe was composed of two optical linear scales installed on the. z and x-axis of work coordinate system on NC lathe and a computer inserted with PC counter card enables to obtain measuring data. Here, ATC(Automatic Tool Changer) and moving part of linear scale are fixed with magnet bases in order to measure displacement of the ATC of NC lathe. And next, computer software was developed in order to measure the lathe under resolution of 0.1㎛ by the linear scales, and also computer soft measuring data could be modeled on plots and be analyzed to numerically.