• 상하수도학회지
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• 제29권2호
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• pp.233-241
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• 2015

Polytetrafluoroethylene (PTFE) membrane has high resistance to chlorine, which is a great advantages in chemical cleaning to recover water flux during membrane processes in drinking water systems. A humic kaolin water with approximately 4 mg/L of DOC and 10 NTU of turbidity was prepared as a feed water. Coagulation pretreatment with or without settling was applied. The coagulation with settling showed the greatest water production. The reduced flux was effectively recovered by NaOCl cleaning, i.e., 21% recovery by 50 mg/L of NaOCl cleaning and 49% recovery by 500 mg/L NaOCl cleaning. The images of SEM and AFM analyses were corresponded to the water flux variation. However, when the floc was accumulated on the membrane surfaces, the efficiency of NaOCl cleaning was substantially limited. In addition, dynamic contact angle became greater after cleaning, which indicates changes in characteristics of fouling layer such as surface hydrophobicity. Proper cleaning technologies during enhanced backwash using NaOCl would expand application of PTFE membranes in drinking water systems.

• 멤브레인
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• 제16권4호
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• pp.259-267
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• 2006

다공성 폴리비닐리덴플루오라이드(PVDF, polyvinylidenefluoride) 그리고 폴리테트라플루오르에틸렌(PTFE, Polytetrafluoroethylene)에 대하여 순수한 물, $0.1M{\sim}4.0M$ NaOH 수용액, 그리고 $0.1M{\sim}3.0M\;NaHSO_3$ 수용액을 사용하여 임계투과압력을 측정하였다. 임계투과압력은 동일한 평균 기공 크기의 PVDF보다 PTFE가 크게 나타남을 관찰할 수 있었다. NaOH 수용액의 경우 NaOH의 농도 증가에 따라 임계투과압력은 감소하였으며 1.0 M 농도에서 최소값을 나타낸 후 다시 증가함을 확인하였다. 그러나 NaOH이 아닌 다른 염을 용해한 수용액인 $NaHSO_3$ 수용액의 경우 농도를 3.0 M까지 증가하여도 임계투과압력이 계속 감소함을 알 수 있었다. 이와 같은 현상을 이론적인 Cantor식으로 해석할 수 있었다.

• Journal of Periodontal and Implant Science
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• 제31권4호
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• pp.689-711
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• 2001

The purpose of this study was to compare clinical results of guided tissue regeneration(GTR) using either a nonresorbable ePTFE membrane or a resorbable membrane made from a synthetic copolymer of glycolide and lactide(PLGA) in the treatment of human class Ⅱ furcation defects. The ePTEE membranes were applied to 16 patients with maxillary molar buccal class Ⅱ furcation defects as Group I, PLGA membranes were applied to 15 patients with maxillary molar buccal class Ⅱ furcation defects as Group Ⅱ, ePTFE membranes were applied to 20 patients with mandibular molar buccal class Ⅱ furcation defects as Group Ⅲ and PLGA membranes were applied to 20 patients with mandibular molar buccal class Ⅱ furcation defects as Group Ⅳ and bone graft materials(DFDBA) were applied in all groups. Probing depth, gingival recession, clinical attachment level, tooth mobility and sulcus bleeding index(SBI) were measured at baseline, 3, 6 and 12months postoperatively. In addition, membrane exposure levels were measured at surgery, 1, 2 and 6weeks postoperatively and postoperative complications were evaluated. The results were as follows: In all groups, there were statistically significant differences in probing depth reduction, gain of clinical attachment and mobility reduction at values of 3, 6 and 12months postoperatively compared to values of baseline, whereas no significant differences in SBI except Group I and gingival recession(p<0.05). Membrane exposure levels were increased at 1, 2 and 6weeks postopratively compared to value of baseline in Group I(p<0.05). There were no statistically significant differences between ePTFE and PLGA membrane in probing depth, clinical attachment level and SBI. There were minimal gingival recession and membrane exposure in Group Ⅳ and pain and swelling were the most common postoperative complications in Group Ⅱ, Ⅲ(p<0.05). In conclusion, this study showed that both nonresorbable membrane and resorbable membrane were effective similarly in the treatment of class Ⅱ furcation defects, without statistical differences in clinical measurements.

• 대한환경공학회지
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• 제30권1호
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• pp.31-36
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• 2008

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(기공크기: 0.1 $\mu$m)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 여과수에 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.

• 한국막학회:학술대회논문집
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• 한국막학회 2008년도 춘계 총회 및 학술발표회
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• pp.189-193
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• 2008

• Maxillofacial Plastic and Reconstructive Surgery
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• 제41권
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• pp.16.1-16.6
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• 2019

Background: Silk mats have been approved for clinical trials by the Korean Food and Drug Administration as membranes for guided tissue regeneration (GTR). In this study, silk mat application was compared to high-density polytetrafluoroethylene (dPTFE) membrane application or no membrane group. Methods: To compare the silk mat group to the dPTFE group or the no membrane group, a retrospective sample collection was conducted. Bony defects were measured at the time of extraction (T0) and then at 3 months (T1) and 6 months after extraction (T2) on a digital panoramic view. Bone gain (BG) was calculated by subtracting from the bony defect at T0 to the bony defect at each follow-up. Results: The BG at T2 was 2.44 ± 2.49 mm, 4.18 ± 1.80 mm, and 4.24 ± 2.05 mm in the no membrane group, silk mat group, and dPTFE group, respectively. Both membrane groups had significantly higher BG than BG in the no membrane group at T2 (P < 0.05). Conclusions: Both membrane groups showed higher BG than the no membrane group.

• 한국구조물진단유지관리공학회 논문집
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• 제20권6호
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• pp.84-90
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• 2016

최근 다양한 형태의 막구조물의 건설이 증가추세이지만 막구조물에 적합하지 않은 내화기준이 적용되어 활용성이 위축되고 있는 실정이다. 그렇기 때문에 막구조물의 건설 활성화에 맞추어서 이에 대한 내화기준의 제 개정이 필요한 상황이다. 따라서 본 연구에서는 일반적으로 많이 사용되는 막재료(ETFE, PVF, PTFE)를 선정하여 막구조물에 화재가 일어났을 때, 시간이 변화함에 따라 온도가 올라가는 막재료의 물리적인 특성 변화와 발열량과 막재료 설치높이와의 상관관계를 파악하여 막구조 내화기준에 기초 자료로 활용하고자 한다.

• 폴리머
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• 제37권5호
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• pp.649-655
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• 2013

방사선 그래프팅 방법을 이용하여 다공성 PTFE 지지체에 친수성 고분자 사슬인 아크릴산 사슬을 도입시켜 강화 복합 연료전지막의 지지체로 사용하기 위한 PTFE 친수화 다공성 지지체를 제조하였고 FTIR을 이용하여 다공성 PTFE에 친수성 고분자가 성공적으로 도입되었음을 확인하였다. 제조된 지지체의 표면 친수화 정도를 관찰하기 위해 접촉각을 측정한 결과, 도입된 친수성 고분자 사슬이 증가할수록 소수성의 PTFE 표면 친수화도가 증가됨을 확인하였다. 또한 제조된 지지체의 물리화학적, 형태학적 특성은 FE-SEM, gurley number, 인장강도를 측정하여 관찰하였다.

• Restorative Dentistry and Endodontics
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• 제24권2호
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• pp.286-298
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• 1999

The endodontic-periodontic combined lesions have been difficult to get correct diagnosis and predictable treatment. This study was to make the experimental endodontic-periodontic combined defects in dogs for the study of the periodontal regeneration and to evaluate the efficacy of the enamel matrix protein and e-PTFE membrane in the experimental endodontic-periodontic combined defects. 5 mongrel dogs were used. The pulp chambers were opened and the plaque was inserted into the chambers to induce the periapical lesions on the mandibular second, third and fourth premolars of the dogs. 1 month later, the root canal treatments were done with gutta perch a and ZOE sealer. On the day of surgery, the periapical defects were standardized by trephine bur. The buccal dehiscence defects were made by the dental bur and bone chisels. The apicoectomy with retrofilling was done. The prepared roots were randomly selected for test and control groups. In the experimental groups, the enamel matrix derivative and e-PTFE membrane were used. Nothing was placed on the control group. Fluroscent labelling was used to evaluate the bone formation. After 4 and 12 weeks, the dogs were sacrificed and undecalcified sections were prepared and stained with toluidine blue. Those histologic sections were examined by fluorescent microscopy and light microscopy. The results were as follows. 1. In the control group, new bone was formed in the periapical defects and scarcely in the buccal dehiscence defects. New cementum was not detected at 4 and 12 weeks. 2. In the experimental groups, new bone, new cementum and periodontal ligament were found in the periapical and buccal dehiscence defects. The relative amount and the quality of the new bone, new cementum and periodontal ligament tissue that had formed on the experimental groups were superior to those of the control group. 3. The current observation implicated that e-PTFE membrane and enamel matrix protein could be the effective tools for the guided tissue regeneration of the endo-perio combined defects.

• 한국화재소방학회논문지
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• 제30권2호
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• pp.35-42
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• 2016

막구조 건축물은 경량의 건축용 막재를 사용하므로 자유로운 곡면표현이 가능하고 시각적인 만족도가 높아 그 사용이 점차 확대되고 있다. 하지만 건축용 막재를 구성하는 직물이 화재에 취약하므로 용도에 적합하며 보다 높은 난연성능을 가지는 불연성 막재의 개발이 요구되고 있다. 따라서 본 연구에서는 단열성, 내열성, 불연성이 우수한 현무암섬유를 건축용 막재의 직포로 적용하고 PTFE 분산 수지를 함침 코팅하여 DSC/TGA 열분석, 강도특성, 방염 및 난연특성을 평가하였다. 또한, 일반적으로 사용되는 건축용 막재 중 성능이 가장 우수한 유리섬유 직포 막재와 난연특성을 비교하였으며 평가결과 현무암섬유 직포의 건축용 막재로서의 가능성을 확인할 수 있었다.