• 폴리머
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• 제38권6호
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• pp.714-719
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• 2014

라이신과 글루코오스에서부터 제조된 카프로락탐과 모폴리논을 음이온 개환중합법을 이용하여 나일론 6-모폴리논 랜덤 공중합체를 합성함으로써 바이오매스 기반의 새로운 나일론을 제조할 수 있었으며 또한 친수성이 향상된 나일론 6을 제조할 수 있었다. 중합 조건을 적절하게 조절함으로써, 점도평균분자량 30000 g/mol과 수율 80%의 공중합체를 제조할 수 있었다. 모폴리논을 공중합 단량체로 사용함으로써 나일론 6의 친수성을 높게 향상시킬 수 있었다. 제조된 나일론 6-모폴리논 랜덤공중합체를 시차주사 열량계(DSC), 열중량 분석기(TGA), X-선 회절분석기(XRD), 점도계, 접촉각 측정기와 같은 분석방법으로 그 특성을 분석하였다.

• 폴리머
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• 제26권5호
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• pp.661-669
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• 2002

본 연구는 이온교환 부직포를 이용하여 대기중의 아황산 가스를 흡착제거 시키기 인하여 가스의 농도는 100~200 ppm, 유속을 0.6~l.0 m/sec, 습도를 30~90 RH%로 하여 SO$_2$의 흡착량을 측정하여 음이온교환 섬유 스크러버의 최적조건을 도출하였다. 이온교환체의 이온교환 용량은 pH=4에서 최대 3.75 meq/9이였으며 또한 유속이 0.5 m/s일 때 흡착평형시간이 30시간으로 최대를 나타냈으며, 온도가 8$0^{\circ}C$일 때 흡착평형시간이 최대 10시간이상 짧아지는 경향을 나타냈다. 농도가 200 ppm의 경우 이온교환 섬유의 리간드와 SO$_2$와의 반응속도가 빨라져 흡착 파과가 빨라지는 경향을 나타냈으며 또한 스크러버 내의 상대습도가 90%일 때 7.6%/h의 제거율을 보였는데 이는 상대습도가 30%일 때 4.6%/h보다 30%정도 높은 제거율을 나타내었으며 또한 5 wt% NaOH 용액으로 5분 이내에 완전 탈착이 되었다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.271-278
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• 2006

We used polymers of alternating cationic and anionic nature to build up shells on fiber surfaces, strengthen the worn-out fibers and improve paper properties made from such fibers. OCC and ONP pulps were either dipped or salted out in the cationic polyallylamine, polyacrylamide and starch solutions. After centrifugal drying, these were followed by treatments in anionic polyacrylic acid, poly-acrylamide, and starch solutions, respectively. The shell-enhanced fibers were formed into handsheets and their physical properties evaluated. The results show that building multiple shells on worn-out fiber surfaces can strengthen the fibers and paper. The simpler and more practical impregnation-centrifuging treatment provided the desired effects, whereas salting out the polymers produced somewhat superior fibers. The latter process, were impractical, however. The first pair of polymeric shells imparted marked strength improvement, whereas later layers had diminishing efficacies. Overall, the methods can improve fiber quality, attaining paper strength requirements without resorting to expensive measures. Alternate cationic polymer and filler powders were also deposited on fiber surface based on the micriparticle system in an anticipation of stiffness gains. Platy minerals, such as montmorillonite, bentonite, sericite, clay and talc were added following cationic PAM. After dewatering of polymer-pigment shelled fiber of one to 3 pairs of layers, handsheets either calendered or uncalendered were evaluated. The results indicate that regardless of calendaring, stiffness of the handsheets did not improve appreciably while certain other strength properties showed gains. We also attempted the novel starch gel filler addition method wherein tapioca starch and filers (PCC, sericite or clay) were mixed at high solids content of 50% and cooked until gelatinized. The filled handsheets were dried under various conditions and then tested for their properties. Improvements in strengths of modified filled paper were observed.

• Korea-Australia Rheology Journal
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• 제14권4호
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• pp.189-201
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• 2002

The interaction between hydrophobically modified hydroxyethyl cellulose (hmHEC), containing approximately 1 wt% side-alkyl chains of $C_{16}$, and an anionic sodium dodecyl sulphate (SDS) surfactant was investigated. For a semi-dilute solution of 0.5 wt% hmHEC, the previously observed behaviour of a maximum in solution viscosity at intermediate SDS concentrations, followed by a drop at higher SDS concentrations, until above the cmc of surfactant when the solution resembles that of the unsubstituted polymer, was confirmed. Additionally, a two-phase region containing a hydrogel phase and a water-like supernatant was found at low SDS concentrations up to 0.2 wt%, a concentration which is akin to the critical association concentration, cac, of SDS in the presence of hmHEC. Above this concentration, SDS molecules bind strongly to form mixed micellar aggregates with the polymer alkyl side-chains, thus strengthening the network junctions, resulting in the observed increase in viscosity and elastic modulus of the solution. The shear behaviour of this polymer-surfactant complex during steady and step stress experiments was examined In great detail. Between SDS concentrations of 0.2 and 0.25 wt%, the shear viscosity of the hmHEC-polymer complex network undergoes shear-induced thickening, followed by a two-stage shear-induced fracture or break-up of the network. The thickening is thought to be due to structural rearrangement, causing the network of flexible polymers to expand, enabling some polymer hydrophobic groups to be converted from intra- to inter-chain associations. At higher applied stress, a partial local break-up of the network occurs, while at even higher stress, above the critical or network yield stress, a complete fracture of the network into small microgel-like units, Is believed to occur. This second network rupture is progressive with time of shear and no steady state in viscosity was observed even after 300 s. The structure which was reformed after the cessation of shear is found to be significantly different from the original state.

• 공업화학
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• 제18권6호
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• pp.607-611
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• 2007

양이온성 천연고분자 물질로서 유전자와 효과적으로 복합체를 형성할 수 있는 저분자량 수용성 키토산(LMWSC)에 유전자 발현 효율을 높이기 위해 histidine을 컨쥬게이션 시킨 유전자 전달체를 제조하였다. 히스티딘-LMWSC의 제조는 무수프탈산으로 LMWSC의 아민기를 보호한 후 히스티딘과 결합한 다음 무수프탈산을 제거하는 반응으로 제조하였다. 제조한 유전자 전달체의 물리화학적 특성은 FT-IR과 NMR 스펙트럼을 통하여 확인하였고, 전기영동 결과로부터 본 실험에서 제조된 유전자 전달체와 DNA가 복합체를 형성하였다는 것을 알 수 있었다. 또한 유전자 전달체의 입자크기는 DLS를 이용하여 측정한 결과 히스티딘-LMWSC-DNA 복합체입자의 크기는 100~200 nm임을 확인하였다. 이로부터 히스티딘을 함유하는 LMWSC가 유전자 전달체로서 사용될 수 있음을 확인하였다.

• Macromolecular Research
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• 제16권8호
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• pp.725-733
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• 2008

Polyimide (PI) multilayer thin films were prepared by spin-coating from a poly(amic acid) (PAA) and poly(amic acid) ammonium salt (PAAS). PI was prepared from pyromellitic dianhydride (PMDA) and 4,4'-oxydianiline (ODA) PAA. Different compositions of PAAS were prepared by incorporating triethylamine (TEA) into PMDA-ODA PAA in dimethylacetamide. PI multilayer thin films were spin-coated from PMDA-ODA PAA and PAAS. The PAAS comprising cationic and anionic moieties were spherical with a particle size of $20{\sim}40\;nm$. Some particles showed layers with ammonium salts, despite poor ordering. Too much salt obstructed the interaction between the polymer chains and caused phase separation. A small amount of salt did not affect the interactions of the interlayer structure but did interrupt the stacking between chains. Thermogravimetric analysis (TGA) showed that the average decomposition temperature of the thin films was $611^{\circ}C$. All the films showed almost single-step, thermal decomposition behavior. The nanostructure of the multilayer thin films was confirmed by X -ray reflectivity (XRR). The LF 43 film, which was prepared with a 4:3 molar ratio of PMDA and ODA, was comprised of uniformly spherical PAAS particles that influenced the nanostructure of the interlayer by increasing the interaction forces. This result was supported by the atomic force microscopy (AFM) data. It was concluded that the relationship between the uniformity of the PAAS particle shapes and the interaction between the layers affected the optical and thermal properties of PI layered films.

• 접착 및 계면
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• 제3권4호
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• pp.27-36
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• 2002

다양한 가능을 가진 고분자 복합재료인 Core-shell 복합인자를 제조하여 부직포 바인더로 사용하기 위하여 유기/유기계 core-shell 에멀젼 중합을 시도하였다. 유기/유기계 Core-shell 중합으로 메틸메타아크릴레이트(MMA), 스티렌(St)의 core와 shell의 단량체, 개시제는 과황산암모늄(APS) 유화제는 도데실벤젠슬폰나트륨(SDBS)의 농도, 교반속도를 변화시켜 전환율, 분자량, 입자경과 입자형태, 유리전이온도, 인장강도를 측정하여 최적반응조건을 산출하였다. 1) PMMA, PSt core와 shell의 입자중합은 각각 개시제의 농도 $1.58{\times}10^{-3}mol/L$와 $4.0{\times}10^{-4}mol/L$가 최적이다. 2) PMMA/PSt의 PMMA core 중합에서 유화제의 농도는 $1.45{\times}10^{-5}mol/L$, PSt/PMMA의 PSt core 중합은 $2.91{\times}10^{-5}mol/L$가 최적이다. 3) 유화중합에 최적교반속도는 200 rpm이며, 입자안정성은 유화제 첨가량과 비례하여 증가하였다. 4) Core-shell 복합입자는 동일조성의 공중합체에 비하여 유리온도 조절이 용이하고, 인장강도값도 높게 측정되었다.

• 공업화학
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• 제10권1호
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• pp.1-5
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• 1999

알킬비닐에테르와 말레인산디에틸에스테르의 공중합체인 측쇄알킬기의 탄소수나 중합도가 다른 올리고머형 음이온성 계면활성제 ($C_mD-Na$)를 분산제로 사용하고 친수성 안료로서 산화철이나 산화티탄의 미립자에 대한 분산성을 비교검토하였다. 그 결과 올리고머형 계면활성제의 동족체는 안료입자 표면에 알킬기가 흡착되므로써 흡착층을 형성하고 있는 입자에 음의 하전을 띠어 분산거동이 다르지만, $C_4D-Na$는 저농도에서도 우수한 분산능을 나타내었다. 그리고 소수성인 ${\alpha}-Fe_2O_3$와 Anatase $TiO_2$는 0.1% 농도 이상의 범위에서도 측쇄알킬기의 탄소수가 $C_8$ 이상인 것이 분산작용에 양호한 것으로 나타났다.

• KSBB Journal
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• 제13권4호
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• pp.418-423
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• 1998

Cellular transfections with cationic liposomes are widely empolyed for gene and oligonucleotide transfer in vitro because of their safety and ease of use. However, they still suffer from the low transfection efficiency comparing with viral vectors. Substantial effort shave been focused on increasing transfection efficiency by supplementing the liposome/DNA complexes(lipoplex) with various components. In this work, we tired three kinds of supplements, Poly-L-lysine(PLL), transferrin and a mixture of anionic lipids(PS/PE/PC), to study their effects on gene transfer yield and gene expression efficiency. PLL, a polycationic polymer, enhanced gene transfer yield by 3 times but the gene expression efficiency was increased only by 1.5 times. this result implies that PLL can enhance the transfection efficiency mainly by increasing the rate of outermembrane transport of lipoplex into the cells. On the other hand, transferrin which can facilitate the gene transfer via ligand-receptor interaction gave not only increased gene transfer yield but also enhanced gen expression efficiency by 2.8 times. Transferrin seems to contribute to the escape of plasmid from endosomes through ligand-receptor recycle mechanism. When the cells were treated with a mixture of anionic lipids for 3 hours before the transfection, gene transfer yield was slightly decreased but the gene expression efficiency was enhanced by 1.9 times. This is presumably due to the accelerated liposome-plasmid dissociation by the anionic lipids, and the increased delivery of plasmid to the nucleus. According to these results, it is clear that the supplementation to ameliorate transfection efficiency with cationic liposomes should be contrived in the direction of increasing delivery of plasmid.

• 대한화학회지
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• 제23권6호
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• pp.402-411
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• 1979

Pyrrolidone의 음이온중합의 새로운 개시제로서 Pyrrolidone-N-sulfonyl chloride를 합성하고, 이 개시제에 의한 중합반응기구를 제안하였으며, 중합결과를 분석 고찰하여 다른 개시제의 경우와 비교하였다. Pyrrolidone-N-sulfonyl chloride의 농도를 작게할 수록 합성되는 고분자의 점도가 증가함을 관찰하였으며, 개시제의 KOH에 대한 비율이 0.25일때 중합속도 및 중합수율이 가장 큰 결과를 얻었다. PNSC/KOH 촉매작용에 의한 pyrrolidone의 음이온 중합은, $CO_2$/KOH 촉매작용의 경우에 비하여 일반적으로 중합속도가 빠르고, 중합수율도 높았다.