• 폴리머
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• 제31권3호
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• pp.194-200
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• 2007

고분자막 저항형 습도센서를 제조하기 위하여 [2-[(methacryloyloxy)ethyl] dimethyl] propylammonium bromide(MEPAB), [2-[(methacryloyloxy)ethyl]-2-hydroxyethyl]dimethylmonium bromide (MEHDAB), n-butyl methylacrylate(BMA), 2-hydroxyethyl methylacrylate(HEMA)와 styrene의 공중합체를 사용하였다. 4가지 종류의 공중합체들 즉 MEPAB/styrene/MEHDAB MEHDAB/BMA/HEMA, MEPAB/BMA/MEHDAB 그리고 MEPAB/styrene/HEMA을 알루미나 기판에 인쇄된 Ag/Pd 전극 위에 blocked-isocyanate 가 교제로 가교시켜 도포하였을 때, 매우 좋은 내수성을 보여주었다. 습도센서의 상대습도에 대한 주파수 의존성, 온도의존성, 히스테리시스, 응답속도 그리고 내수성을 평가하였다. MEPAB/BMA/MEHDAB= 3/6/1 공중합체의 경우, $30{\sim}90%RH$ 범위에서 $2.9 M{\Omega}$에서 $1.84k{\Omega}$의 저항을 보여주었으며 좋은 직선성과 낮은 히스테리시스를 보여주었다.

• 폴리머
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• 제31권4호
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• pp.302-307
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• 2007

저항형 습도센서를 제조하기 위하여 [2-[(methacryloyloxy)ethyl]dimethyl] propylammonium bromide(MEPAB), [2-[(methacryloyloxy)ethyl]-2-hydroxyethyl]dimethylammonium bromide(MEHDAB), 2-[(methacryloyloxy)ethyl]trimethylammonium chloride(METAC), 그리고 n-butyl methylacrylate(BMA)의 공중합체를 사용하였다. 4가지 종류의 4원 공중합체 MEPAB/BMA/MEHDAB/METAC=4/4/1/1, 3/5/1/1, 2/6/1/1, 1/7/1/1을 blocked-isocyanate가교제를 사용하여 Ag/Pd 전극/알루미나에 도포한 후 좋은 내수성을 보여주었다. 습도센서의 상대습도에 대한 주파수 의존성, 온도 의존성, 히스테리시스, 응답속도 그리고 내수성을 평가하였다. MEPAB/BMA/MEHDAB/METAC=2/6/1/1 공중합체의 경우, $30{\sim}90%RH$에서 $1.4\;M{\Omega}{\sim}2.9\;k{\Omega}$의 저항을 보여주었으며 좋은 직선성과 작은 히스테리시스를 보여주었다.

• Macromolecular Research
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• 제11권5호
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• pp.322-327
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• 2003

Two kinds of mutually cross-linkable copolymers were prepared to be used as humidity-sensing materials. The humidity-sensitive thin films consist of cross-linked polyelectrolytes of the following component: 4-vinylbenzyl dimethyl 2-(dimethylphosphino)ethyl phosphonium chloride (1)/ bis(2-methoxyethyl)itaconate (2)= 3/l, 2/l, 1/1 and 1/2 and 4-vinylbenzyl chloride (3)/ vinylbenzyl tributyl phosphonium chloride (4)= 3/l, 2/l, 1/1 and 1/2. The humidity sensor prepared from the reaction of 1/2= 2/l with 3/4= 2/l showed an average resistance of 723,36.2 and 2.42 ㏀ at 30, 60 and 90%RH, respectively. Temperature dependence, frequency dependence, and response time were measured and the reliability test such as water durability and long-term stability were also estimated.

• Biomaterials and Biomechanics in Bioengineering
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• 제2권2호
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• pp.97-109
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• 2015

A series of amphiphilic graft copolymers were synthesized by varying the number of graft chains and graft chain lengths. The polarity of the hydrophobic graft chain on the copolymers was varied their solution properties. The glass transition temperature of the copolymers was in the low-temperature region, because of the amorphous nature of poly (trimethylene carbonate) (PTMC). The surface morphology of the lyophilized colloid gel had a bundle structure, which was derived from the combination of poly(N-hydroxyethylacrylamide)( poly(HEAA)) and PTMC. The solution properties were evaluated using dynamic light scattering and fluorescence measurements. The particle size of the graft copolymers was about 30-300 nm. The graft copolymers with a higher number of repeating units attributed to the TMC (trimethylene carbonate) component and with a lower macromonomer ratio showed high thermal stability. The critical association concentration was estimated to be between $2.2{\times}10^{-3}$ and $8.9{\times}10^{-2}mg/mL$, using the pyrene-based fluorescence probe technique. These results showed that the hydrophobic chain of the graft copolymer having a long PTMC segment had a low polarity, dependent on the number of repeating units of TMC and the macromonomer composition ratio. These results demonstrated that a higher number of repeating units of TMC, with a lower macromonomer composition, was preferable for molecular encapsulation.

• Archives of Pharmacal Research
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• 제20권4호
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• pp.324-329
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• 1997

AB-type amphiphilic copolymers (abbreviated as LE) composed of poly (L-leucine) (PLL) as the A component and poly (ethylene oxide) (PEO) as the B component were synthesized by the ring-opening polymerization of L-leucine N-carboxy-anhydride initiated by methoxy polyoxyethylene amine $(Me-PEO-NH_2)$ and characterized. Core-shell type nanoparticles were prepared by the diafiltration method. Particle size distribution obtained by dynamic light scattering was dependent on PLL composition and the size for LE-1, LE-2 and LE-3 was $369.6{\pm}267$, $523.4{\pm}410$ and $561.2{\pm}364 nm$, respectively. Shapes of the nanoparticies observed by transmission electron microscope (TEM) were almostly spherical. The critical micelle concentration (CMC) of the nanoparticles determined by a fluorescence probe technique was dependent on the composition of hydrophobic PLL, and the CMC for LE-1, LE-2 and LE-3 was $2.0{\times}10^{-6},1.7{\times}10^{-6}$ and $1.5{\times}10^{-6}(mol/l) $, respectively. Clonazepam release from core-shell type nanoparticles in vitro was dependent on PLL composition and drug loading content.

• 한국재료학회지
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• 제3권4호
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• pp.344-351
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• 1993

폴리(에틸렌 테레프탈레이트 -코-1,4-시클로헥실렌 디메틸렌 데레프탈레이트), P(ET-CT), 공중합체의 결정구조를 CPMAS NMR분광법을 이용하여 해석하였다. 결정화 시료에서 메틸렌기에 의한 공명 피크를 CT와 ET성분으로 분리시켜 분석한 결과, 0-20 몰%의 CT조성을 갖는 공중합체는 bulky한 CT성분이 PET결정격자에서 배제되고 66-100 몰 100%의 CT조성을 갖는 공중합체는 PCT결정격자 내부에 ET성분이 부분적으로 혼입되는 것을 확인할 수 있었다. 이와 같은 결정구조의 공중합 조성 의존성은 ET와 CT의 반복단위 길이와 결정격자의 크기가 다르기 때문인 것으로 추정된다.

• Fibers and Polymers
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• 제3권1호
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• pp.8-13
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• 2002

The effect of block sequence on the self-assembly of ABC-type triblock copolymers in the ordered state is investigated using an isothermal-isobaric molecular dynamics simulation. The block sequence has an important effect ,on the ]norphology of ABC triblock copolymers. Different morphologies are observed depending on the block sequence as well as the block composition. The triblock copolymers with the volume fraction of 1 : 1 : 1 ($f_A$=$f_B$=$f_C$= 0.33) show the three phase and four layered lamellar structures irrespective of the block sequence. The $A_{32}$$B_{16}$$C_{32}$triblock copolymer with $f_B$=0.2 shows a morphology In which cylinders of midblock B are formed at the interface between A and C lamellae, whereas the morphology of triblock copolymer $B_{16}$$C_{32}$ $A_{32}$ and $C_{32}$ $A_{32}$ $B_{16}$ show a cylindrical core-shell structure and a lamellar type morphology, respectively. The $A_{20}$$B_{40}$$C_{20}$the triblock copolymer with the block B as a major component shows a tricontinuous structure, whereas both $B_{40}$$C_{20}$$A_{20}$ and $C_{20}$$A_{20}$$B_{40}$ triblock coolymers exhibit the lamellar structures. When the block B has larger volrome fraction with $f_B$=0.75, the matrix is composed of block B, and other two blocks A and C form spherical domains.

• 대한의용생체공학회:의공학회지
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• 제12권1호
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• pp.57-62
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• 1991

ABA type block copolymers composed of poly($\gamma-benzyl$ L-glutamate) (PBLG) as the A component and poly (ethylene glycol) as the B component were obtained by polymerization of $\gamma-benzyl$ L-gletamate N -carboxyanhydride, initiated by amino groups at both ends of poly(ethylene glycol) . From circular dichroism measurements in ethylene dichloride solution as well as from infrared spectTa measurements in solid state, it was found that the polypep- tide block exists in the a-helical conformation, as in PBLG homopolymer. $Poly-N^5$ (3-hydroxypropyl glutamine) (PHPG)/poly(ethylene glycol)block copolymer hydrogel was obtained by the treatment of PBLG/PBG block copolymer with the mixture of 3-ammine-1-propanol and diamlnooctane. The water content of PHPG/PEG block copolymer hydrogel was about 80wt% when the concentration of crosslinking agent was below 5 mole % per polymer.

• 공업화학
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• 제5권3호
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• pp.379-384
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• 1994

ethylene-vinyl alcohol(EVOH) 공중합체와 styrene-maleic anhydride(SMA) 공중합체를 포함하는 일련의 블렌드계에서 상용화 정도가 결정성 고분자 분산상의 결정화 거동에 미치는 영향을 조사하였다. 블렌드의 결정화거동과 morphology는 각각 시차열량분석기(DSC) 및 주사전자현미경(SEM)을 사용하여 확인하였다. 상용화 정도에 따라 분산상의 결정화 중 일부분이 저온 영역으로 크게 이동하여 나타났다 상용화 블렌드계에서 나타나는 이러한 결정화온도의 이동은 분산상의 homogeneous crystallization에 기인한 것이었다.

• 멤브레인
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• 제32권5호
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• pp.292-303
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• 2022

이산화탄소 배출이 없는 고분자 전해질 막 연료전지(polymer electrolyte membrane fuel cell, PEMFC)는 수송용, 발전용 시스템에 적용 가능한 친환경 에너지 변환장치이다. PEMFC의 주요 구성품 중 하나인 고분자 전해질 막(polymer electrolyte membrane, PEM)은 구동시간 동안의 높은 수소 이온 전도도와 물리화학적 안정성 갖춘 과불소화계 고분자(perfluorinated sulfonic acid, PFSA) 기반 PEM (PFSA-PEM)이 상용화 되어있다. 하지만 PFSA-PEM의 단점으로 지적되는 낮은 유리전이온도와 높은 기체 투과도의 보완이 요구되고 있다. 이에 본 총설에서는 PFSA-PEM의 성능 향상 및 단점 보완을 위해 1) PFSA의 측쇄부 길이를 조절함으로써 이온교환용량의 증가와 고분자의 결정성을 증가시켜 PFSA-PEM의 능력을 향상시킨 연구와 2) 유/무기 첨가제를 도입하여 수소 이온 전도도 및 물리적 안정성을 향상시키는 복합 막 연구 및 3) 다공성 지지체를 도입하여 PEM의 두께를 효과적으로 감소시켜 막 저항을 효과적으로 줄이고 내구성을 큰 폭으로 개선한 다공-충진막에 관한 연구를 소개하고자 한다.