• Title/Summary/Keyword: pore-filled

Search Result 134, Processing Time 0.019 seconds

Preparation of Pore-filled Ion-exchange Membranes using Poly(vinylbenzyl ammoninum salt) (Poly(vinylbenzyl ammonium salt)를 이용한 Pore-filled 이온교환막의 제조)

  • 변홍식
    • Membrane Journal
    • /
    • v.11 no.3
    • /
    • pp.109-115
    • /
    • 2001
  • Pore-filled ion-exchange membranes in which polypropylene(PP) microporous membrane was used as a nascent membrane were prepared by an in-situ cross-linking technique. Poly(vinylbenzyl chloride)(PVBCI) reacted with piperazine(PIP) or 1,4-diaminobicyclo[2,2,2]octane(DABCO) in a di-methylforamide(DMF) solution was filled in the pores of the microporous base membrane. After gellation the remaining chloromethyl groups were, then reacted with an amine such as trimethylamine to form positively charged, ammonium site. This will produce the pore-filled anion-exchange membrane. It was shown that this simple 2 step procedure gave dimensionally stable, pore-filled membranes in which the MG of polymer gel and degree of cross-linking could be easily controlled by the concentration of PVBCI and cross-linker in the starting DMF solution. Specially, high water permeability (7.8 kg/$m^2$hr, host membrane: PP3, MG: 73%, degree of cross-linking: 10%, crosslinker: PIP) at ultra low pressure(100 kPa) indicates the produced pore-filled membranes is usable as a water softening membrane.

  • PDF

Development of Pore-filled Ion-exchange Membranes for Efficient All Vanadium Redox Flow Batteries

  • Kang, Moon-Sung
    • Journal of the Korean Electrochemical Society
    • /
    • v.16 no.4
    • /
    • pp.204-210
    • /
    • 2013
  • Thin pore-filled cation and anion-exchange membranes (PFCEM and PFAEMs, $t_m=25-30{\mu}m$) were prepared using a porous polymeric substrate for efficient all-vanadium redox flow battery (VRB). The electrochemical and charge-discharge performances of the membranes have been systematically investigated and compared with those of commercially available ion-exchange membranes. The pore-filled membranes were shown to have higher permselectivity as well as lower electrical resistances than those of the commercial membranes. In addition, the VRBs employing the pore-filled membranes exhibited the respectable charge-discharge performances, showing the energy efficiencies (EE) of 82.4% and 84.9% for the PFCEM and PFAEM, respectively (cf. EE = 87.2% for Nafion 1135). The results demonstrated that the pore-filled ion-exchange membranes could be successfully used in VRBs as an efficient separator by replacing expensive Nafion membrane.

Preparation and Application of Pore-filled PVDF ion Exchange Membranes (Pore-filled PVDF 이온교환막의 제조 및 응용)

  • 변홍식;박병규;홍병표;여광수;윤무홍;강남주
    • Membrane Journal
    • /
    • v.14 no.2
    • /
    • pp.108-116
    • /
    • 2004
  • In this study, the pore-filled ion-exchange membranes were prepared by using the asymmetric PVDF membrane as a nascent membrane. First, the solution of PVBCI having the chlorornethylate aryl ring of 80 percents and DABCO was made with the mixed solvent of THF and DU (8:2). These mixed solution was then, filled in the pores of PVDF membrane, and left for a day to complete the gelation. Finally the pore-filled anion-exchange membrane is obtained fallowed by the amination of the remaining chloromethyl groups with trimethylamine (TMA, 40 wt% in water) forming the positive ammonium ion sites. This 2 step procedure enabled us to produce the pore-filled membranes without change of size, and to control the properties of final membrane with various degree of cross-linking. The results of SEM and AFM showed the polyelectrolyte existed in the pores of nascent membrane as a certain configuration. From the investigation of the solvent affecting much to the permeability and rejection, it was found that the membranes using mixed solvent of THE and DMF (8:2) showed better performances than the membranes produced by THF only. The result of an investigation for the water permeability of the final membrane at low pressure (100 Kpa) showed a typical ultrafiltration membrane's permeability (8 ∼ 10 kg/$m^2$hr) and good values of rejection (55∼60 percent).

Preparation and Characterization of Pore-filled Membrane Based on Polypropylene with Poly(vinylbenzyl chloride) by Using in-situ Cross-linking Technique

  • Kwon, Byeong-Min;Ko, Moon-Young;Hong, Byung-Pyo;Byun, Hong-Sik
    • Korean Membrane Journal
    • /
    • v.10 no.1
    • /
    • pp.13-19
    • /
    • 2008
  • Water softening is a very promising field for membranes and especially ultra low pressure membranes. Nanofiltration membranes based on pore-filling technology was prepared by using a new technique: the in-situ cross-linking. This route involves introducing a pre-formed polymer into the pores of a host membrane and then locking the polymer in the pores by in-situ cross-linking with an appropriate reagent. By this way, it is possible to make robust and competitive, pore-filled, anion-exchange membranes with excellent control over the properties of the incorporated gel without affecting the host membrane. In this paper, the possibilities of tuning such membranes for ultra low pressure water softening was examined by altering pore-filling chemistry (by changing cross-linking and aminating reagents). The results showed that tuning the chemistry of the pore-filling has important effects. In particularly, it had been shown that the correct selection of cross-linking reagent was not only essential to get pore-filled membranes but it could control their properties. Moreover, the aminating reagent could improve membrane performance. It was found that an increase in hydrophobicity could improve the Darcy permeability.

Preparation and Electrochemical Applications of Pore-filled Ion-exchange Membranes with Well-adjusted Cross-linking Degrees: Part II. Reverse Electrodialysis (가교도가 조절된 세공충진 이온교환막의 제조 및 전기화학적 응용: Part II. 역 전기투석)

  • Song, Hyun-Bee;Moon, Ha-Neul;Kim, Do-Hyeong;Kang, Moon-Sung
    • Membrane Journal
    • /
    • v.27 no.5
    • /
    • pp.441-448
    • /
    • 2017
  • In this study, the effects of membrane characteristics on the power generation performance in reverse electrodialysis (RED) have been investigated with pore-filled ion-exchange membranes (PFIEMs) prepared by employing a porous polyethylene substrate and the mixtures of three cross-linking agents. As a result, it was confirmed through the correlation analyses that the cross-linking degree and free volume of the PFIEMs were effectively controlled by mixing the cross-linking agents having different molecular sizes, influencing complexly the electrochemical characteristics of the membranes and the power generation performance in RED. In particular, the pore-filled cation-exchange membranes at the optimum cross-linking conditions exhibited the power generation performance superior to that of the commercial membranes and the pore-filled anion-exchange membranes also showed the excellent performance close to that of the commercial membrane.

The Effect of Pressure on the Properties of Carbon/Carbon Composites during the Carbonization Process

  • Joo, Hyeok-Jong;Oh, In-Hwan
    • Carbon letters
    • /
    • v.3 no.2
    • /
    • pp.85-92
    • /
    • 2002
  • 4D carbon fiber preforms were manufactured by weaving method and their carbon fiber volume fractions were 50% and 60%. In order to form carbon matrix on the preform, coal tar pitch was used for matrix precursor and high density carbon/carbon composites were obtained by high densification process. In this process, manufacture of high density composites was more effective according to pressure increasement. When densificating the preform of 60% fiber volume fraction with 900 bar, density of the composites reached at 1.90 $g/cm^3$ after three times processing. Degree of pressure in the densification process controls macro pore but it can not affect micro pore. During the carbonization process, micro pore of the preform were filled fully by once or twice densification processing. But micro pore were not filled easily in the repeating process. Therefore, over three times densification processing is the filling micro pore.

  • PDF

Optimum Design of Pore-filled Anion-exchange Membranes for Efficient All-vanadium Redox Flow Batteries (효율적인 전 바나듐 레독스 흐름 전지를 위한 세공충진 음이온교환막의 최적 설계)

  • Kim, Yu-Jin;Kim, Do-Hyeong;Kang, Moon-Sung
    • Membrane Journal
    • /
    • v.30 no.1
    • /
    • pp.21-29
    • /
    • 2020
  • In this study, we have established the optimum design condition of pore-filled anion-exchange membrane for all-vanadium redox flow battery (VRFB). From the experimental results, it was proven that the membrane design factors that have the greatest influence on the charge-discharge performance of VRFB are the ion exchange capacity, the porosity of substrate film, and the crosslinking degree. That is, the ohmic loss and the crossover of active materials in VRFB were shown to be determined by the above factors. In addition, two methods, i.e. reducing the ion exchange capacity at low crosslinking degree and increasing the crosslinking degree at high ion exchange capacity, were investigated in the preparation of pore-filled anion-exchange membranes. As a result, it was found that optimizing the crosslinking degree at sufficiently high ion exchange capacity is more desirable to achieving high VRFB charge-discharge performances.