• Korea-Australia Rheology Journal
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• 제15권1호
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• pp.1-7
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• 2003

A new method is introduced to build up organic/organic multilayer films composed of cationic poly(allylamine hydrochloride) (PAH) and negatively charged poly (sodium 4-styrenesulfonate) (PSS) using the spinning process. The adsorption process is governed by both the viscous force induced by fast solvent elimination and the electrostatic interaction between oppositely charged species. On the other hand, the centrifugal and air shear forces applied by the spinning process significantly enhances desorption of weakly bound polyelectrolyte chains and also induce the planarization of the adsorbed polyelectrolyte layer. The film thickness per bilayer adsorbed by the conventional dipping process and the spinning process was found to be about 4 ${\AA}$ and 24 ${\AA}$, respectively. The surface of the multilayer films prepared with the spinning process is quite homogeneous and smooth. Also, a new approach to create multilayer ultrathin films with well-defined micropatterns in a short process time is Introduced. To achieve such micropatterns with high line resolution in organic multilayer films, microfluidic channels were combined with the convective self-assembly process employing both hydrogen bonding and electrostatic intermolecular interactions. The channels were initially filled with polymer solution by capillary pressure and the residual solution was then removed by the .spinning process.

• Macromolecular Research
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• 제17권4호
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• pp.245-249
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• 2009

A fluorescing, copolymer(Q)-bearing, quaternary ammonium pendant was mixed with excess natural salmon sperm DNA with a molecular weight of $1.3{\times}10^6$(2,000 base pairs) to afford highly fluorescing, complex mixtures. The fluorescence life-time of the polymer Q was greatly increased when mixed with DNA: for the mixture of Q:DNA=1:750 the fast and slow decay lifetimes increased from ca. 10 to 100 ps and from 20 ps to ca. 1 ns, respectively. The enhanced fluorescence of the mixtures was ascribed to efficient compartmentalization and reduced conformational relaxation of the polymer Q by complexation with excess DNA.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 1999년도 Proceedings of Pre-symposium of the 10th ISWPC
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• pp.34-42
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• 1999

The present investigation has focused up on the study of the adsorption of three different molecular mass fractions of a polyDiMethylDiAllylAmmoniumChloride (DMDAAC) (8750(LM\ulcorner), 48000(MM\ulcorner) and 1200000(HM\ulcorner)) on bleached chemical fibres. Both kinetics of adsorption and equilibrium adsorption measurements have been conducted and each adsorption has been measured by polyelectrolyte titration. The results show that the LM\ulcorner polymer can reach all of the charges in the fibre wall whereas the MM\ulcorner and HM\ulcorner can only reach the external surfaces of the fibres. It is also shown that the kinetics of adsorption of the LMw polymer is not at all affected by the presence of a saturated layer of HMw polymer on the surface of the fibres. Finally, the results from the investigation show that it is possible to have full coverage of the external surface of the fibres by a high molecular mass polymer and a full coverage of the internal surface of the fibres with a low molecular mass polymer. This is true if the high molecular masspolymer is added first followed by addition of the low molecular masspolymer.

• Membrane and Water Treatment
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• 제9권2호
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• pp.87-94
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• 2018

The interactions of water soluble polymers with dye are studied by ultrafiltration using a molecular weight cut off of 10 KDa regenerated cellulose ultrafiltration membrane. Two water-soluble polymers, namely Poly (Sodium-4 Styrenesulfonate) (PSS) and Poly (Vinyl Alcohol) (PVA) were selected for this study. The effects of process parameters, such as, polyelectrolyte concentrations, transmembrane pressure, ionic strength and pH of solution on dye retention and permeation flux were examined. PSS enhanced ultrafiltration achieved dye retention as high as 99% as a result of complexation between polyanion containing aromatic groups and cationic dye. This result was confirmed by the red shift. The retention of dye decreases as the salt concentration increases, a high retention was obtained at pH above 4. However, in case of PVA, relatively low retention (50%) was observed. Ionic strength and pH has no significant effect on the removal of MB. The permeate flux depended slightly on polyelectrolytes concentrations, transmembrane pressure, salt concentration and pH.

• 대한화학회지
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• 제42권1호
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• pp.84-91
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• 1998

고분자 전해질 복합체 형성이 poly(N-isopropyl acrylamide)(PNIPAAm) 공중합체의 저임계 용해온도 (lower critical solution temperature, LCST)에 미치는 영향을 조사하기 위하여 N-isopropyl acrylamide (NIPAAm)와 acrylic acid (AAc)를 선택하여 온도 감응성과 pH 감응성을 동시에 지니는 pH/온도감응성 고분자를 합성하였다.합성된 고분자들을 FT-IR과 적정실험을 통해 확인하였다. 고분자전해질로서 poly(allylamine) (PAA)과 poly(L-lysine)(PLL)을 사용하여 pH 2로부터 12에 이르는 넓은 범위의 pH 영역에서 고분자전해질 복합체 형성이 pH/온도감응성 고분자의 LCST에 미치는 영향을 조사하였다. 수용액상에서 poly(NIPAAm-co-AAc)중 PNIPAAm의 LCST는 cloud-point 측정 방법으로 결정하였다. 또한 역적정 실험을 통해 공중합체 중의 AAc 함량을 결정하고 AAc의 이온화 정도가 LCST에 미치는 영향을 조사하였다. 수용액상에서 poly(NIPAAm-co-AAc) 중 PNIPAAm의 LCST는 pH, 고분자전해질의 존재 유무, AAc의 함량, 그리고 고분자 사슬에 존재하는 전하밀도 등에 큰 영향을 받았다. 고분자전해질 복합체는 PAAc의 pKa와 PAA또는 PLL의 pKb 사이인 중성영역에서 형성됐으며 PNIPAAm의 LCST에 미치는 PLL의 영향은 PAA에 비해 크게 나타났다.

• 펄프종이기술
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• 제32권4호
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• pp.27-33
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• 2000

A new technique for fractionating pulp stock into a long fiber portion and fines fraction was developed by KRICT in order to enhance the drainage and strength properties of recycled OCC pulp. In order to investigate the effect of fines contents in stock and stages of flotation on fractionation efficiency, flotations were performed at varied fines contents and flotation stages. Based on the result of multi-stage flotation fractionation it could be said that fines smaller than 15${\mu}{\textrm}{m}$ stabilize flotation froth of OCC. Although the amounts and the fines contents of flotation reject could be increased by multi-stage flotation fractionation of OCC, flotation stages more than 3 times were found to be inefficient in terms of fines concentrating degree. In order to satisfy the both conditions of reducing long fiber loss and of increasing flotation reject, several kinds of fractionating promoters were searched and investigated. And high molecular weight cationic polyacrylamide was chosen as a long fiber flocculating and flotation froth-stabilizing agent.

• 펄프종이기술
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• 제44권5호
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• pp.8-13
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• 2012

The flexography ink has disadvantage in a deinking process because it tends to form too fine particles in alkali condition to be removed in flotation deinking. The influence of pH conditions on the particle size of phthalocyanine cyan ink used for flexo-printing was investigated to see the effect of pH conditions on flexography ink dispersion. Flexography ink particles prepared by grinding dried ink films were used in this experiment. Greater reduction of the ink particle size was noticed under alkaline pH condition, which was attributed to dissolution of resin component of the ink. Adsorption behavior of flexography ink onto pigment particles was examined using clay and talc as substrate pigments. Pretreatment of inorganic pigments with a cationic poly-DADMAC increased the surface adsorption of flexography ink particles, which improved the removal of the inks by centrifugal sedimentation of inorganic pigments. Most efficient removal of the ink particles was achieved when an optimal addition level of the cationic polymer was used for pretreatment of inorganic pigments, and this optimal addition level corresponds to the surface saturation point of the polyelectrolyte. Adsorption of flexography ink particles onto inorganic pigments improved the ink removal in flotation deinking since the pigment particles has the optimal particle size for flotation deinking.

• 한국미생물·생명공학회지
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• 제23권6호
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• pp.763-769
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• 1995

As a mean to recover photosynthetic bacterial(PSB) cells and its practical uses in food industrial wastewater treatment, various biodegradable polyelectrolytes were first investigated for flocculation of suspended colloids in the PSB treatment process of soybean curd wastewater. Anionic polyelectrolytes such as sodium alginate and carrageenan were not effective but a cationic polyelectrolyte chitosan isolated from Portunus trituberclatus showed very effective flocculation activity. The concentration of chitosan, pH and temperature of wastewater for maximal flocculation were 40 mg/l, pH 7 and room temperature, respectively. Test using deacetylated chitosan to various degree showed higher flocculating activities in samples deacetylated over 75% and time for maximum flocculation was 40 min by stirring slowly under the above optimal conditions. Chitosan was not only effective to flocculate cells but also removed COD and MLSS of the wastewater. COD of 42% and MLSS of 87% were removed by addition of chitosan to the soybean curd wastewater treated with PSB.

• 대한의용생체공학회:의공학회지
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• 제9권1호
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• pp.73-78
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• 1988

The polymer electrolyte complex hydrogels consisting of poly (methacrylic acid) and poly (4-vinylpyrridine) were formed and 5-flurouracil and pilocarpine drugs were loaded on their hydrogels. Cumulative 5-FU released from PEC hydrogel was affected by the degree of loading and release rate of 5-FU was followed by the monolithic type. Cumulative pilocarpine released from PEC hydrogel increased by ionic interaction between cationic pilocarpine and anionic PMA. Release rate showed the zero order after burst effect.

• 멤브레인
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• 제23권4호
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• pp.304-311
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• 2013

발효공정으로부터 생산된 유기산의 회수를 위하여 나노여과 분리막 공정을 이용하는 경우 유기산을 제외한 발효액 내 존재하는 당, 단백질 등의 부산물을 배제하면서 유기산을 선택적으로 투과시킬 수 있는 나노여과막이 요구된다. 본 연구에서는 발효액으로부터 분자량이 상대적으로 작고 카르복실산기를 갖는 유기산의 효과적인 회수를 위하여 분리막 표면에 양전하를 도입하여 전기적 인력에 의해 젖산의 투과도를 향상시킬 수 있는 신규 나노여과 분리막을 제조하였다. 분리막 표면에 고분자 전해질 PEI (Polyethyleneimine)를 그라프팅시켜 제조된 분리막의 제타전위 측정 결과 표면 층이 양전하를 나타내는 것을 확인하였다. 실제 젖산 용액 배제율 확인 결과 고분자 전해질 그라프팅 층이 형성된 막에서 배제율이 크게 감소하는 것으로 보아 그라프팅 층에 의한 젖산 배제율 저감에 효과를 나타내었다.