• Macromolecular Research
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• 제12권5호
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• pp.451-458
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• 2004

Water-soluble polyacrylamides hydrophobically modified with small amounts of N,N-dialkylacrylamides [N,N-dihexylacrylamide (DHAM) and N,N-dioctylacrylamide (DOAM)] have been prepared through free radical solution polymerizations using two hydrophobic initiators derived from 4,4' -azobis(4-cyanopentanoic acid) (ACVA) and long linear chains consisting of 12 and 16 carbon atoms (C12 and C16). This procedure resulted in polyacrylamides containing hydrophobic groups along the chain as well as at the chain ends. We compare the properties of this class of polymers, termed "combined associative polymers", with those of the multisticker (with hydrophobic groups along the polymer chain) and telechelic (with hydrophobic groups at the chain ends) associative polymers. These materials were prepared using DHAM or DOAM and a hydrophobic initiator (ACVA) modified with alkyl chains of two different lengths. Polymers having molecular weights (M$\_$w/) of ca. 175,000 and hydrophobic contents [H] of ca. 0.8 mol% were prepared using 0.07 mol% of initiator relative to the total monomer feed. We investigated the effects that the type, localization, and concentration of the hydrophobic groups have on the viscosities of the associative polymer solutions.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 가을 학술발표회 논문집
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• pp.169-170
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• 2003

There was little development in transparent conductive polymer films and their limited studies have been mainly focused on polymer films coated by water-soluble PEDOT doped with the polymeric counteranion poly(4-styrenesulfonate) (PEDOT-PSS)[1-3]. However PEDOT-PSS as coating material has some difficulties because of high viscosity and low solubility in organic solvent except for in water. In this study, in order to extend practical applications of PEDOT and to prepare conductive PC films, we tried to prepare PEDOT-coated PC films and investigated their conductivity and thermal stability. (omitted)

• 한국건축시공학회지
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• 제9권5호
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• pp.71-77
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• 2009

시멘트 혼화용 폴리머 디스퍼션은 시멘트 모르타르 및 콘크리트 내부에서 폴리머 필림을 형성하여 각종 역학적성 질 및 내구성을 향상시킨다. 본 연구는 3종류의 폴리머 디스퍼션을 폴리머 시멘트비 0, 5, 10, 20%로 변환한 폴리머 시멘트 모르타르를 제작, 투수시험을 실시하여 투수성능을 실험하였으며, 더욱이 폴리머 시멘트 슬러리를 폴리머 시멘트 모르타르 표면에 도포하여 방수성능의 개선효과를 평가하였다. 또한 보통시멘트 콘크리트 표면에 폴리머 시멘트 슬러리를 도포하여 시멘트 콘크리트와 폴리머 시멘트 슬러리의 건조수축을 측정하였다. 그리고 기본적인 역학적 성상인 휨강도와 압축강도를 측정하여 보통 시멘트 모르타르와 비교 검토하였다. 연구결과, 폴리머 시멘트 모르타르는 보통 시멘트 모르타르에 비해 방수성능과 강도가 크게 개선되었으며, 폴리머 시멘트 슬러리의 건조수축은 시멘트 콘크리트에 비해 4-5배 크게 나타났다. 또한 향후 건조수축에 따른 접착성능의 영향성에 대한 연구가 진행되어야 할 것이다.

• 폴리머
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• 제39권1호
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• pp.33-39
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• 2015

올메사탄은 BCS 2단계에 해당하는 약물로 물에 잘 녹지 않는 난용성 약물이다. 이런 약물이 낮은 생체이용률과 제형을 설계하는 과정에서 어려움을 주는 원인이 된다. 본 연구에서는 올메사탄을 분무건조법 및 회전용매증 발법을 이용해 고체분산체를 제조하여 제법에 따른 난용성약물의 용출률을 확인하였다. 수용성 고분자로 PVP를 사용하여 약물과 고분자의 비율별로 고체분산체를 제조하였다. SEM을 이용하여 고체분산체의 형태학적인 특성을 분석하였고, 고체분산체의 결정학적 성질은 XRD와 DSC를 통하여 확인하였다. 또한 FTIR을 통해 화학적인 변화를 확인하고, 생체 외 용출거동 실험을 통하여 변화된 용출률을 확인하였다. 제조된 고체분산체는 pH 1.2에서 용출을 확인하였으며, 올메텍과 용출률을 비교하였으며, 분무건조를 통해 약물의 용출률을 향상시킬 수 있다는 것을 확인할 수 있다.

• 센서학회지
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• 제2권1호
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• pp.35-40
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• 1993

$Si_{3}N_{4}$ 박막의 코팅된 pH-ISFET의 게이트 부위 위에 lipase 효소를 고정화하여 FET(field effect transistor) 형지질(lipid) 센서를 제조하였다. 효소 고정화막 형성 물질로는 수용성 고분자인 polyvinyl alcohol(PVA)에 감광성기인 1-methyl-4-(formylstyryl) pyridinium methosulfate(SbQ)를 결합시킨 PVA-SbQ를 사용하였다. PVA-SbQ 수용액 (SbQ 1mole %, 10 wt%) $200{\mu}L$, bovine serum albumin (BSA) 7.5 mg, lipase 10 mg으로 구성 된 현탁액을 사용한 사진식각(photolithographic) 공정의 최적 조건은 피막의 상온 진공 건조 시간 45분, spin coater의 회전수 $5,000{\sim}6,000$ rpm, UV 노광시간 $20{\sim}30$초, 증류수 현상 시간 $30{\sim}40$초로 나타났다. 이렇게 구성된 지질 센서는 triacetin을 지질 시료로 하였을 때 $10{\sim}100$ mM의 농도 범위에서 직선성의 검정선을 나타내었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2001년도 학술논문발표회
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• pp.163-168
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• 2001

This study examinated the application in construction field and the development of waterproofing material system by the spray water-soluble rubber asphalt to solve the problems of synthetic polymer sheet and gio membrane(A mat sheet of Bentonite) that had been used domestic waterproofing material in advance. As the result of study, characters of study water-souble rubber asphalt are the follows; 1) The amount of water absorption was '0.06'g and the seepage quantity was '0'g in result. 2) The tensile strength was about 30.7kgf/$cm^2$ and the elongation was about 72.4% in result. 3) After reliance of temperature test had been ended, the tensile strength was about 72.4kg/$cm^2$ in low temperature and about 30.7kgf/$cm^2$ in normal temperature. 4) After acid and alkaline treatment had been ended, the tensile strength was about 19.7kgf/$cm^2$ and about 21.9kgf/$cm^2$ in result. 5) After chlorine ion treatment had been ended, the tensile strength was 28.5kgf/$cm^2$ and the elongation was 250% in result. So, this study can propose the spray water-soluble rubber asphalt to satisfy the security and durability of waste filled land.

• Membrane and Water Treatment
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• 제7권2호
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• pp.101-113
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• 2016

In this study, to improve the water flux of porous hydrophobic membranes, various water-soluble polymers including neutral, cationic and anionic polymers were adsorbed using 'salting-out' method. The adsorbed hydrophobic membrane surfaces were characterized mainly via the measurements of contact angles and scanning electron microscopy (SEM) images. To enhance the durability of the modified membranes, the water-soluble polymers such poly(vinyl alcohol) (PVA) were crosslinked with glutaraldehyde (GA) and found to be resistant for more than 2 months in vigorously stirred water. The water flux was much more increased when the ionic polymers used as the coating materials rather than the neutral polymer and in this case, about 70% of $0.31L/m^2{\cdot}h$ (LMH) to 0.50 LMH was increased when 300 mg/L of polyacrylamide (PAAm) was used as the coating agents. Among the cationic coating polymers such as poly(styrene sulfonic acid-co-maleic acid) (PSSA_MA), poly(acrylic acid-comaleic acid) (PAM) and poly(acrylic acid) (PAA), PSSA_MA was found to be the best in terms of contact angle and water flux. In the case of PSSA_MA, the water flux was enhanced about 80%. The low concentration of the coating solution was better to hydrophilize while the high concentration inclined to block the pores on the membrane surfaces. The best coating condition was found: (1) coating concentration 150 to 300 mg/L, (2) ionic strength 0.15, (3) coating time 20 min.

• 한국분말재료학회지
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• 제31권3호
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• pp.263-271
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• 2024

This study focused on improving the solubility of silodosin, a drug poorly soluble in water, by utilizing solid dispersions. Three types of dispersions were examined and compared against the drug powder: surface-attached (SA), solvent-wetted (SW), and solvent-evaporated (SE). Polyvinyl alcohol (PVA) was identified as the most effective polymer in enhancing solubility. These dispersions were prepared using spray-drying techniques with silodosin and PVA as the polymer, employing solvents such as water, ethanol, and a water-acetone mix. The physicochemical properties and solubility of the dispersions were evaluated. The surface-attached dispersions featured the polymer on a crystalline drug surface, the solvent-wetted dispersions had the amorphous drug on the polymer, and the solvent-evaporated dispersions produced nearly round particles with both components amorphous. Testing revealed that the order of improved solubility was: solvent-evaporated, solvent-wetted, and surface-attached. The results demonstrated that the preparation method of the solid dispersions significantly impacted their physicochemical properties and solubility enhancement.

• 한국건축시공학회지
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• 제1권2호
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• pp.165-173
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• 2001

This study examinated the application in construction field and the development of waterproofing material system by the spray water-soluble rubber asphalt to solve the problems of synthetic polymer sheet and gio membrane(A mat sheet of Bentonite) that had been used domestic waterproofing material in advance. As the result of study, characters of study water-soluble rudder asphalt are the follows: 1) The amount of water absorption was '0.06'g and the seepage quality was '0'g in result. 2) The tensile strength was about 30.7kgf/$\textrm{cm}^2 and the elongation was about 72.4% in result. 3) After reliance of temperature test had been ended, the tensile strength was about 72.4kgf/$\textrm{cm}^2 in low temperature and about 30.7kgf/$\textrm{cm}^2 in normal temperature. 4) After acid and alkaline treatment had been ended, the tensile strength was about 19.7kgf/$\textrm{cm}^2$ and about 21.9kgf/$\textrm{cm}^2 in result. 5) After chlorine ion treatment had been ended, the tensile strength was 28.5kgf/$\textrm{cm}^2$ and the elongation was 250% in result. 6) The impact performance was subsided at 1.5m height. 7) After promotion weathering had been ended, the tensile and elongation was about 26.0kgf/$\textrm{cm}^2, 214% in result. So, this study can propose the spray water-soluble rubber asphalt to satisfy the and durability of waste filled land.

• Elastomers and Composites
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• 제48권4호
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• pp.294-299
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• 2013

수용성 단량체인 메타크릴산 (MAA)을 단량체로 potassium persulfate (KPS)를 개시제로 이용하여 $70^{\circ}C$에서 $90^{\circ}C$ 사이의 선택된 온도에서 용액중합을 진행하였다. 물에 대한 메타크릴산의 농도가 감소하거나 개시제의 농도가 증가하면 분자량은 감소하였다. 중합반응온도는 폴리메타크릴산 (PMAA)의 분자량에 크게 영향을 미치지 않았다. Weissenberg 효과는 대부분의 반응온도에서 나타났으며, $90^{\circ}C$에서는 약하게 관찰되었다. 대부분의 중합반응에서 분산성지수는 1.5 이하로 관찰되었다. 교반속도가 증가하면서 분자량은 점진적으로 증가하다, 교반속도가 800 rpm에 이르면서 수평균 및 중량평균분자량이 동일하게 791,000 g/mol의 분자량을 갖는 단분산성의 PMAA가 구하여졌다. 유리전이온도는 $162^{\circ}C$로 측정되었다.