만성 뇌경막하 혈종 외막의 병리조직소견과 외막 투과성에 대한 연구

박윤관,이기찬,이훈갑 대한신경외과학회 1995 Journal of Korean neurosurgical society Vol.24 No.4

Permeability of membrane of chronic SDH is a unique characteristic. And various types of attenuation of chronic subdural hematoma(SDH) appearing on computerized tomography(CT) scans are related to the changes occurring as the result of recurrent bleeding. The authors have investigated the membrane permeability of SDH according to the histological changes of the outer membrane of chronic SDH. A consecutive seires of 19 adult patients with chronic subdural hematoma has been studied in respect to the post-operative subdural drainage after burr-hole craniostomy and closed system drainage. The subdural drain was kept for 5 days. The amount and the pattern of daily drainage were correlated with histological findings of the outer membrane. The outer membrane of chronic SDH was very rich in blood vessels and contains giant capillaries. One electron microscopic finding of giant capillaries was the frequent formation of gap junctions between adjacent endothelial cells. Numerous red or white blood cells was spilling into the interstitial space of the outer membrane. In positive cases to both membrane hemorrhage and surface clot, total amount of drainage was significantly different from the cases without these findings(p=0.0263). In cases without membrane hemorrhage, the presence of migrating inflammatory cell was well correlated with total drainage amount(p=0.028). From these findings it is suggested that endothelial gap junction of macrocapillaies might play an important role in permeability of the outer membrane. But the recent episode of bleeding could act as a barrier and decrease the permeability actually. After resolution of fibrin clot infiltrated inflammatory cells which contribute to fibrinolysis would decrease and then the permeability would increase.

통기성을 갖는 막재료의 흡음특성

정정호(Jeong-Ho Jeong),김규제(Ku-Je Kim),김정중(Jung-Joong Kim) 한국생활환경학회 2010 한국생활환경학회지 Vol.17 No.6

Membrane structures are widely used for constructing large space such as gymnasium and stadiums. The use of sound absorption membrane system are increasing in stadiums and arenas, however research on the sound absorption characteristics were not so much investigated. Kiyama (1996), Hashimoto (1996) and Sakagami (2005) conducted theoretical studies on the sound absorption and sound insulation properties of single and double leaf permeable membrane. In this study, sound absorption characteristics of each membrane were investigated by experiments in reverberation chamber. 4 types of permeable membranes and a non-permeable membrane were used for experiments. Air space behind membrane material and tension on the membrane was varied. Sound absorption performance of permeable membrane materials was investigated. As increasing air space behind the membrane material, sound absorption coefficient was increased. In a resonance absorption frequency band sound absorption coefficient varied more dramatically. Sound absorption characteristics were flat in mid and high frequency range and sound absorption coefficient was from 0.3 to 0.5. Also sound absorption coefficient was increased by the increment of surface density and air permeability of membrane. However, over the certain value of air permeability and surface density sound absorption coefficient was decreased. These results can be used as design factors and method for the room acoustic design of dome-stadiums and large free-form buildings.

Hybrid membranes with low permeability for vanadium redox flow batteries using in situ sol-gel process

Su Mi Park,김혜경 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.12

Vanadium redox flow batteries (VRFBs) have been researched as large energy storage systems due to their long cycle life, high energy efficiency, low cost, and flexible design. However, cation exchange membranes are permeable to the vanadium ions in aqueous acidic electrolyte, and vanadium ions crossover reduces the efficiency and capacity of VRFBs. To improve membrane selectivity, proton conducting inorganic materials are proposed for the modification of conventional membranes, e.g., Nafion. Clusters inside Nafion membrane are filled with inorganic materials using in situ sol-gel processes, and this results in homogeneous distribution of inorganic materials. Hybrid membranes with Nafion 115 (coded as HN115) exhibit comparable ionic conductivity and a 70% reduced permeability to vanadium ions compared with pristine Nafion 115 (coded as N115). The columbic and energy efficiencies of VRFBs with HN115 at 20mA∙cm−2 exhibit higher values of 95% and 80% in their columbic and energy efficiencies, respectively; VRFBs with N115 exhibit 78% and 70%, respectively. The capacity performance is also improved when HN115 is used in VRFBs. The VRFBs with hybrid membranes (lower permeable membrane) show higher columbic efficiency than the VRFB with N115. HN115 exhibit similar columbic efficiency values of 95% over entire current ranges, which are almost unrelated to the current density. However, N115 shows a fluctuating and lower columbic efficiency of 75%, 88%, 93% at 20mA∙cm−2, 40mA∙cm−2, 80mA∙cm−2, respectively. VRFB with N115 (high conductive membrane) exhibits lower voltage drops for discharging and higher energy efficiency at high current ranges. With these results, it is proposed that the energy efficiencies of VRFBs are compromised with membrane conductivity and permeability. The columbic efficiencies are more contributed by membrane permeability. The permeability properties are more dominant in low current density and the ionic conductivity is more effective in high current ranges. To obtain higher performance of VRFBs, the membrane design for selectivity should be considered according to the operation conditions.

PEMFC의 고분자막에서 지지체가 고분자전해질 막 성능 및 전기화학적 내구성에 미치는 영향

오소형 ( Sohyung Oh ),임대현 ( Dae Hyun Lim ),이대웅 ( Daewoong Lee ),박권필 ( Kwonpil Park ) 한국화학공학회 2020 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.58 No.4

To increase the mechanical durability of the proton exchange membrane fuel cells, a reinforced membrane in which a support is placed in the polymer membrane is used. The support mainly uses e-PTFE, which is hydrophobic and does not transfer ions, which may cause performance degradation. In this study, we investigated the effect of e-PTFE support on PEMFC performance and electrochemical durability. In this study, the reinforced membrane with the support was compared with the single membrane (non-reinforced membrane). Due to the hydrophobicity of the support, the water diffusion coefficient of the reinforced membrane was lower than that of the single membrane. The reinforced membrane had a lower water diffusion coefficient, resulting in higher HFR, which is the membrane migration resistance of ions, than that of a single membrane. Due to the low hydrogen permeability of the support, the OCV of the reinforced membrane was higher than that of the single membrane. The support was shown to reduce the hydrogen permeability, thereby reducing the rate of radical generation, thereby improving the electrochemical durability of the reinforced membrane.

Low permeable composite membrane based on sulfonated poly(phenylene oxide) (sPPO) and silica for vanadium redox flow battery

Sadhasivam, T.,Kim, Hee-Tak,Park, Won-Shik,Lim, Hankwon,Ryi, Shin-Kun,Roh, Sung-Hee,Jung, Ho-Young Elsevier 2017 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.42 No.30

<P><B>Abstract</B></P> <P>The proton conductivity and vanadium permeability of organic-inorganic (sulfonated poly (phenylene oxide) (sPPO)-nano sized sulfonated silica (sSiO<SUB>2</SUB>)) hybrid membrane were investigated for application in a vanadium redox flow battery (VRFB) system. Significant attention is being paid to PPO polymers as a replacement for Nafion<SUP>®</SUP> membranes due to their relatively low cost and ease of sulfonation. The attachment of a sulfonic acid (SO<SUB>3</SUB>H) functional group to PPO and SiO<SUB>2</SUB> was confirmed using Fourier Transform Infrared Spectroscopy (FTIR). The hybrid membrane (sPPO-2% sSiO<SUB>2</SUB>) exhibited increased thermal stability, water uptake (WU), ion exchange capacity (IEC) and proton conductivity (IC) compared with a conventional organic sPPO membrane. The proton conductivity of the hybrid membrane increased considerably compared to sPPO alone, resulting from the 2% sSiO<SUB>2</SUB> nanoparticles added homogeneously to the polymer matrix. The proton conductivities of the sPPO and hybrid membranes were 0.050 and 0.077 S/cm, respectively. The increased proton conductivity of the hybrid membrane was attributed to the enhanced hydrophilic properties of SO<SUB>3</SUB>H in the membranes. In addition, inorganic particles in the polymer matrix acted as a barrier for vanadium ion crossover. During VRFB unit cell operation, vanadium ion (VO<SUP>2+</SUP>) crossovers were measured as 14.66, 1.955 and 0.173 mmol L<SUP>−1</SUP> through Nafion<SUP>®</SUP>212, sPPO and hybrid membranes, respectively, and VO<SUP>2+</SUP> permeability were 2.22 × 10<SUP>−7</SUP>, 2.50 × 10<SUP>−8</SUP> and 4.76 × 10<SUP>−9</SUP> cm<SUP>2</SUP> min<SUP>−1</SUP> for Nafion<SUP>®</SUP>212, sPPO and hybrid membranes, respectively. Based on our experimental results, low cost organic-inorganic hybrid membranes as prepared provide an efficient alternative membrane material for advanced VRFB systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel Organic-Inorganic hybrid structured membrane for advanced VRFB system. </LI> <LI> PPO as a replacement for Nafion<SUP>®</SUP> membranes due to low cost and ease of sulfonation. </LI> <LI> Proton conductivity increased to hybrid membrane (0.077 S/cm) compared to sPPO alone. </LI> <LI> VO<SUP>2+</SUP> permeability of sPPO-sSiO<SUB>2</SUB> membrane is significantly lower than Nafion<SUP>®</SUP>212. </LI> <LI> sSiO<SUB>2</SUB> in the sPPO polymer matrix acted as a barrier for vanadium ion crossover. </LI> </UL> </P>

Pore-filling polymer electrolyte membrane based on poly (arylene ether ketone) for enhanced dimensional stability and reduced methanol permeability

Mong, Anh Le,Yang, Sungwoo,Kim, Dukjoon Elsevier 2017 Journal of membrane science Vol.543 No.-

<P><B>Abstract</B></P> <P>We synthesized sulfonated poly (arylene ether ketone) (SPAEK) with an 80% degree of sulfonation (DS) from 4,4-bis(4-hydroxyphenyl) valeic acid and 4,4-difluorobenzophenone. A series of pore-filling membranes were prepared by filling SPAEK into the plasma-treated porous poly (arylene ether ketone) membrane (PAEK) with various pore sizes and porosity. The porous PAEK membrane were obtained by removing the phase separated polylatide (PLA) blocks from the self-arranged PAEK-b-PLA copolymer membranes. The results from synthesis of SPAEK and porous PAEK was characterized using <SUP>1</SUP>H NMR and FTIR, and the morphology of the SPAEK-filled porous PAEK membrane was investigated using SEM and EDX-SEM. The essential properties of pore-filled membranes (e.g., ionic exchange capacity (IEC), proton conductivity, thermal and mechanical stability, and methanol permeability), were examined and collated to those of pristine SPAEK and commercial Nafion 117 membranes. The pore-filled membranes prepared in this study showed enhanced thermal and dimensional stability and reduced methanol permeability compared with the pristine SPAEK and Nafion 117 membranes. The pore-filled membrane with a pore diameter of 50nm showed the highest proton conductivity among all pore-filled membranes and lower methanol permeability than commercial membrane Nafion 117.</P> <P><B>Graphical abstract</B></P> <P>Filling porous PAEK membranes with SPAEK electrolyte is newly developed to enhance the performance of direct methanol fuel cells. From experimental observations, the pore filling membranes show not only a lower methanol permeability and better selectivity than those of pristine SPAEK and Nafion 117 membranes, but also superior thermal and dimensional stabilities.</P> <P>[DISPLAY OMISSION]</P>

침지형 막 분리 활성슬러지법에서 막의 재질 및 구조가 파울링에 미치는 영향

최재훈(Jae Hoon Choi),김형수(Hyung Soo Kim) 大韓環境工學會 2008 대한환경공학회지 Vol.30 No.1

본 연구는 도시하수 처리를 위한 침지형 막 분리 활성슬러지법(membrane bioreactor: MBR) 시스템에서 막 재질 및 구조가 파울링에 미치는 영향을 조사하기 위하여, polytetrafluoroethylene(PTFE), polycarbonate(PCTE) 및 polyester(PETE)의 정밀여과 막(기공 크기: 0.1 μm)을 사용하였다. 120일의 운전기간 동안 PETE막 여과속도는 다른 막들에 비해 가장 빠른 감소경향을 보였으나, 화학세정을 할수록 점차 PCTE 및 PTFE막과 유사한 여과속도 감소경향을 보였다. PETE막의 유기물 제거율이 다른 막들에 비해 약간 높게 나타났으며, 이것은 막의 빠른 파울링 발생과 밀접한 관련이 있는 것으로 판단된다. 반응조내 슬러지 상징액 및 막 여과 수에 존재하는 DOC성분을 친수성 및 소수성으로 분획한 결과, 본 연구에서는 막의 친수성/소수성이 MBR 파울링에 미치는 영향이 크지 않은 것으로 나타났다. 파울링이 발생한 막들의 각종 여과저항 값을 분석한 결과, PETE막은 비가역적 파울링에 의한 영향이 다른 막들에 비하여 컸으며, 유기물 제거율에도 긍정적인 영향을 미친 것으로 판단된다. This work was performed to evaluate the effect of membrane material and structure on fouling in a submerged membrane bioreactor(MBR). Three types of microfiltration membranes with the same pore size of 0.1 μm but different materials, polytetrafluoroethylene(PTFE), polycarbonate(PCTE) and polyester(PETE), were used. While PETE membrane exhibited the most rapid flux decline throughout the operation, PCTE and PTFE had a similar tendency with regard to permeability. Difference in permeability between PETE and the other membranes gradually decreased with time, which was probably due to chemical cleaning. The higher TOC rejection of PETE membrane could be attributable to its faster fouling, resulting from a larger amount of foulants to get attached to the membrane in a shorter time. DOC fractionation using a DAX-8 resin showed that the composition of each fraction between the supernatant and permeates did not change significantly with operation time, indicating that membrane hydrophilicity/hydrophobicity was not a dominant factor affecting to MBR fouling in this study. Compared to other membranes, the fouling of PETE membrane was more influenced by pore clogging (irreversible fouling), which would probably contribute to a higher organic rejection of the PETE membrane.

Effects of membrane characteristics on performances of pressure retarded osmosis power system

Sung Soo Hong,Won Ryoo,전명석,정귀영 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.7

Effects of the characteristics of membrane such as water permeability-coefficient, solute permeability-coefficient, and membrane resistivity on the performances of the spiral wound module in the PRO system have been studied numerically. Fluxes of water and solute through membrane, and concentrations and flow rates in the channels were obtained. The water flux through membrane increases almost linearly with the water permeability-coefficient, but it is insensitive to the solute permeability-coefficient. Decreasing the membrane resistivity makes the water flux through membrane and the power density increase. Effects of the membrane resistivity on the water flux through membrane and flow rates in the channels are small when the difference between the inlet-pressures of draw- and feed-channel is large and vice versa. The power density increases and then decreases as the channel-inlet pressure difference increases. The maximum power density is 16 W/m2 at 14 atm of the channel-inlet pressure difference in our system.

PTMSP/LDH 복합막의 탄화수소 기체투과 특성

정연임,이현경,Jeong, Yeon-Eim,Lee, Hyun-Kyung 한국막학회 2014 멤브레인 Vol.24 No.6

PTMSP[Poly(1-trimethylsilyl-1-propyne)]에 LDH (layered double hydroxide)의 함량을 0, 1, 3, 5 wt%로 달리하여 PTMSP/LDH 복합막을 제조하고, PTMSP/LDH 복합막의 LDH 함량에 따른 $H_2$, $N_2$, $CH_4$, $C_3H_8$, $n-C_4H_{10}$의 기체투과도와 선택도를 조사하였다. PTMSP/LDH 복합막의 LDH 함량이 0~5 wt%로 증가하면 $H_2$와 $N_2$의 투과도는 점차 감소하였고, $n-C_4H_{10}$의 투과도는 급격히 증가하였다. 그리고 $CH_4$와 $C_3H_8$의 투과도는 0~3 wt% 범위에서는 감소하고 3~5 wt% 범위에서는 증가하였다. PTMSP/LDH 복합막의 LDH 함량이 5 wt%로 증가하면 $H_2$와 $N_2$에 대한 $H_2$, $N_2$, $CH_4$, $C_3H_8$, $n-C_4H_{10}$의 선택도는 점차 증가하였고, $CH_4$에 대한 $C_3H_8$과 $n-C_4H_{10}$의 선택도는 0~3 wt% 범위에서는 증가하고, 3~5 wt% 범위에서는 감소하였다. PTMSP/LDH 복합막의 $CH_4$과 $n-C_4H_{10}$의 투과도가 증가하면 $H_2$와 $N_2$에 대한 $CH_4$과 $n-C_4H_{10}$의 선택도는 증가하였고, $n-C_4H_{10}$의 투과도가 증가하면 $CH_4$에 대한 $n-C_4H_{10}$의 선택도는 $n-C_4H_{10}$의 투과도 182,000 barrer까지는 증가하다가 그 이상에서는 감소하였다. $C_3H_8$의 투과도가 증가하면 $H_2$와 $N_2$에 대한 $C_3H_8$의 선택도는 $C_3H_8$의 투과도 46,000~50,000 barrer 범위에서는 감소하고 50,000~52,300 barrer 범위에서 증가하였고 52,300~60,000 barrer 범위에서는 감소하였다. 그리고 $C_3H_8$의 투과도가 증가하면 $CH_4$에 대한 $C_3H_8$의 선택도는 52,300 barrer까지는 급격히 감소하였고, 그 이상에서는 급격히 증가하였다. PTMSP/LDH composite membranes were prepared by adding 0, 1, 3, and 5 wt% LDH contents to PTMSP. The gas permeability and selectivity for $H_2$, $N_2$, $CH_4$, $C_3H_8$, $n-C_4H_{10}$ were investigated as a function of LDH content. As LDH content of PTMSP/LDH composite membranes increased to 5 wt%, the gas permeability for $H_2$ and $N_2$ gradually decreased, while $n-C_4H_{10}$ permeability rapidly increased. The gas permeability for $CH_4$ and $C_3H_8$ was found to decrease for the membranes with LDH content range of 0~3 wt%, however increase in the range of 3~5 wt%. As LDH content of PTMSP/LDH composite membranes increased to 5 wt%, the selectivity of membranes gradually increased for $H_2$, $N_2$, $CH_4$, $C_3H_8$, $n-C_4H_{10}$ over $H_2$, $N_2$. However the selectivity for $C_3H_8$ and $n-C_4H_{10}$ over $CH_4$ increased in the range of LDH content 0~3 wt% but decreased in the range of 3~5 wt%. The $CH_4$ and $n-C_4H_{10}$ selectivity over $H_2$ and $N_2$ increased as $CH_4$ and $n-C_4H_{10}$ permeability increased. The $n-C_4H_{10}$ selectivity over $CH_4$ increased with increasing $n-C_4H_{10}$ permeability up to 182,000 barrer and decreased above 182,000 barrer of $n-C_4H_{10}$ permeability. The $C_3H_8$ selectivity over $H_2$ and $N_2$ was found to decrease as the $C_3H_8$ permeability increased from 46,000 to 50,000 barrer, but to increase with increasing permeability from 50,000 to 52,300 barrer and decrease again with increasing permeability from 52,300 to 60,000 barrer. The $C_3H_8$ selectivity over $CH_4$ was found to decrease with increasing $C_3H_8$ permeability up to 52,300 barrer but increase above 52,300 barrer.

Poly(ether-block-amide)/GPTMS 하이브리드 분리막을 이용한 이산화탄소와 메탄의 투과특성

이근철 ( Keun Chul Lee ),김현준 ( Hyunjoon Kim ) 한국화학공학회 2016 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.54 No.5

Poly(ether-block-amide)(PEBAX®) resin is a thermoplastic elastomer combining linear chains of hard-rigid polyamide block interspaced soft-flexible polyether block. It was believed that the hard polyamide block provides the mechanical strength and permselectivity, whereas gas transport occurs primarily through the soft polyether block. The objective of this work was to investigate the gas permeation properties of carbon dioxide and methane for PEBAX®-1657 membrane, and compare with those obtained for other grade of pure PEBAX®, PEBAX®-2533 and PEBAX® based hybrid membranes. The hybrid membranes based PEBAX® were obtained by a sol-gel process using GPTMS ((3 glycidoxypropyl) trimethoxysilane) as the only inorganic precursor. Molecular structure and morphology of membrane were analyzed by 29Si-NMR, DSC and SEM. PEBAX®-2533 membrane exhibited higher gas permeability coefficients than PEBA ®-1657 membrane. This was explained by the increase of chain mobility. In contrast, ideal separation factor of CO2/CH4 for PEBAX®-1657 membrane was higher than PEBAX®-2533 membrane. It was explained by the decrease of diffusion selectivity caused by increase of chain mobility. For PEBAX®/GPTMS hybrid membrane, gas permeability coefficients were decreased with reaction time. Gas permeability coefficient of CH4 was more significantly decreased than CO2. It can be explained by the reduction of chain mobility caused by the sol-gel process, and strong affinity of PEO segment with CO2. Comparing with pure PEBAX®-1657 membrane, ideal separation factor of CO2/CH4 for PEBAX®/GPTMS hybrid membrane has decreased to 4.5%, and gas permeability coefficient of CO2 has increased 3.5 times.