• Macromolecular Research
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• 제16권4호
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• pp.360-366
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• 2008

Poly(dialkoxyphenylene 1,3,4-oxadiazole)s were conveniently synthesized to compare their material properties of solvent solubility, thermal stability and molecular alignment with respect to alkyl chain length and meta/para-phenylene structure. All prepared polymers exhibited good solubility in co-solvents containing various volume levels of chloroform to trifluoroacetic acid. Meta-polymers showed slightly better solubility than para-polymers. All polymers produced were thermally stable up to $320^{\circ}C$. Photoluminescence of polymer films was observed with blue light emission at around 450 nm. X-ray diffraction patterns of all polymers indicated that they were composed of stacked molecular sheets with the same layer-to-layer distance of $3.4\;{\AA}$. However, side chain-to-side chain and main chain-to-main distances within the layers increased with increasing alkyl chain lengths. The meta-polymer chains were separated more than the para-polymer chains.

• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1443-1454
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• 2011

Methods to prepare novel second-order nonlinear optical (2O-NLO) materials composed of all-silica zeolite (silicalite-1) and a series of 2O-NLO molecules having high second order hyperpolarizability constants (${\beta}$ values) are reviewed. These methods include the development of novel methods to incorporate a series of hemicyanine (HC) molecules into the channels of silicaite-1 films in uniform orientations. The first method is to incorporate HC molecules tethered with long alkyl chains (octadecyl or longer) into the silicalite-1 channels with the long alkyl chain side first through the hydrophobic-hydrophobic interaction between the long alky chains and the silicalite-1 channels. The second method is to incorporate the HC molecule tethered with a medium length alkyl chain (nonyl) into the silicalite-1 channels with the medium length alkyl chain side first through hydrophobic-hydrophobic interaction between the medium length alky chain in the photoexcited state and the silicalite-1 channels. The third method is to incorporate the HC molecule tethered with propionic acid into the silicalite-1 channels with the propionic acid side last mediated by a tetrabultylammonium cation ion-paired to the propionate unit. A method to prepare a novel third-order nonlinear optical (3O-NLO) material composed of zeolite-Y and PbS or PbSe quantum dots is also reviewed. This Account thus describes a promising new direction to which the search for highly sensitive 2O-NLO and 3O-NLO materials has to be conducted and a new direction to which zeolite research and applications have to be expanded.

• Bulletin of the Korean Chemical Society
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• 제30권5호
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• pp.1009-1011
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• 2009

Nano-structured conducting polypyrroles were synthesized in the ionic liquids (ILs) based on 1-alkyl-3-methylimidazolium family with tetrachloroferrate as an anion ($C_n\;mim\;[FeCl_4]\;with\;n\;=\;4,\;8,\;and\;12$). The polypyrrole nanostructures synthesized in ILs were formed as spherical shapes. For ionic liquids with alkyl side chain length $C_4,\;C_4\;mim\;[FeCl_4]$, the size of particles was ranged around 60-nm with a relatively narrow size distribution. As the length of alkyl chain increases, the particle sizes become larger and their distributions become wider. The self-assembled local structures in the solvent ionic liquids are likely to serve as templates of highly organized nano-structured polymers. The length of the alkyl chain in ionic liquids seems to affect these local structures.

• Food Science and Biotechnology
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• 제17권1호
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• pp.176-179
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• 2008

Amylose contents and amylopectin chain architecture of sorghmn and waxy sorghum starches were determined and compared with those of other common cereal and tuber starches. Also, in vitro digestibility of sorghum starch was estimated using a novel methodology. The absolute amylose content of sorghum starch was similar to that of com and wheat starches. The side chain length distribution patterns for sorghum and waxy sorghum amylopectin were very similar to those of com and waxy com, respectively. The $k_{cat}/K_m$ values for sorghum and potato amylopectin did not show a significant difference. The kinetic parameters could be used as novel indicators for starch digestibility.

• Bulletin of the Korean Chemical Society
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• 제35권9호
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• pp.2679-2683
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• 2014

Mechanisms underlying the impacts of interactions between carbon nanoparticles (CNPs) and ionic liquids (ILs) on the physicochemical behavior of CNPs need to be more full worked out. This manuscript describes a theoretical investigation at multiple levels on the interactions of fullerene $C_{60}$ with 21 imidazolium-based ILs of varying alkyl side chain lengths and anionic types and their impacts on $C_{60}$ dispersion behavior. Results show that ${\pi}$-cation interaction contributed to mechanism of the $C_{60}$-IL interaction more than ${\pi}$-anion interaction. The calculated interaction energy ($E_{INT}$) indicates that $C_{60}$ can form stable complex with each IL molecule. Moreover, the direction of charge transfer occurred from IL to $C_{60}$ during the $C_{60}$-IL interaction. Quantitative models were developed to evaluate the self-diffusion coefficient of $C_{60}$ ($D_{fullerene}$) in bulk ILs. Three interpretative molecular descriptors (heat of formation, $E_{INT}$, and charge) that describe the $C_{60}$-IL interactions and the alkyl side chain length were found to be determinants affecting $D_{fullerene}$.

• Bulletin of the Korean Chemical Society
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• 제19권2호
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• pp.178-183
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• 1998

Carbon-13 CP-MAS NMR techniques were used to investigate dynamics of new combined type liquid crystalline polymers, poly[oxy-1,4-phenyleneoxy-2-{6-(4-(4-butylphenylazo)phenoxy)hexyloxy}terephthaloyl] and poly[oxy-1,4-phenyleneoxy-2-{10-(4-(4-butylphenylazo)phenoxy)decyloxy}terephthaloyl]. Noticeable mobility change of either aromatic groups or methylene groups is not detected between 25 ℃ and 82 ℃ from 13C spinlattice relaxation time in the rotating frame (T1ρ(C)) and contact time array experiments. However, line shape analysis shows the increase of mobility of methylene carbons in poly[oxy-1,4-phenyleneoxy-2-{6-(4-(4-butylphenylazo)phenoxy)hexyloxy}terephthaloyl] at higher temperature. The dynamics of side chanis does not seem to be affected in our experimental temperature range by the length of aliphatic chain which is connecting the side chain group to the main chain.

• 공업화학
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• 제29권4호
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• pp.405-412
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• 2018

알칸디올로부터 유래된 주사슬의 탄소수가 6, 9, 11인 bis[3-(dialkyloxylphosphorothionyl)thio-2-methylpropanyloxy]alkane (BAPA)를 합성하였으며, 이를 zinc dialkyl dithiophosphates (ZDDP)와 비교하여 마모억제성능을 살펴보았다. 탄소 주사슬의 길이에 따른 BAPA의 내마모성능을 확인하기 위하여 4-ball 시험을 하였다. 기유무게의 1% 농도로 첨가제를 넣고 WSD (wear scar diameter)를 측정하였고, 각 0.472, 0.459, 0.480 mm로 나타났다. 또한 BAPA 화합물 중 bis[methacryloyloxy]nonane (BMOO9)의 곁사슬인 dialkyl dithiophosphoric acid (DDP)의 탄소수를 4, 8, 12로 변화시켜 합성하여, 4-ball 시험을 하였다. 그 결과로 WSD의 값은 각각 0.537, 0.459, 0.531 mm로 측정되었다. 곁사슬이 짧으면 필름이 얇게 형성되고, 길면 필름형성을 방해하여 탄소수가 8개일 때의 값이 제일 좋게 나타났다. ZDDP의 경우 동일한 조건에서 WSD의 값이 0.563 mm로 측정되었고, 합성한 BAPA의 화합물이 마모억제용 첨가제로 더 우수한 성능을 갖는다는 것을 확인하였다.

• 한국산학기술학회논문지
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• 제10권11호
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• pp.3060-3065
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• 2009

알콕시 곁사슬을 갖는 유연한 곁사슬을 갖는 전방향족 Poly(ether-ether-ester)가 ether기로 연결된 triad diol과 2,5-dialkoxyterephthalic acid로부터 direct polycondensation에 의하여 합성되었다. 중합체의 구조와 물리적 성질은 1H-NMR, FT-IR, DSC, TGA를 이용하여 조사되었다. 연구결과에 의하면, 용매로서 1,1,2,2-tetrachloroethane(TCE)를 사용하여 측정된 고분자의 고유점성도는 0.45~0.86 이/g의 값을 나타내었으며, 질소 분위기하에서 측정된 초기열분해온도는 378~418 $^{\circ}C$를 나타내었다. 중합체 대부분은 측정에 사용된 유기용매에 용해되었고, 용융전이온도(Tm)는 곁사슬의 길이가 길수록 감소되었으며 홀수-짝수 효과를 나타내었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.583-585
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• 2004

In this paper, we synthesized a new photo-crosslinkable polyitaconimide containing cinnamoyl moiety by radical polymerization. Also, the NLC alignment capabilities on these photopolymer surfaces were studied. Good LC alignment with W exposure on the polyitaconimide surfaces can be obtained. A homogenous alignment using UV exposure on the polyitaconimide with 1-carbon chain cinnamoyl group and 4-carbon chain cinnamoly group can be obtained. However, the homeotripic alignment using UV exposure was observed on polyitaconimide with 6-carbon chain cinnamoyl. The LC aligning ability on the polyitaconimide depends on the side chain length of photopolymer.

• 폴리머
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• 제26권4호
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• pp.439-444
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• 2002

n-Alkyloxy기를 가지는 4가지 종류의 서로 다른 benzilidene anhydrides (2a~d)를 4-(n-alkyloxy)benzaldehyde (1a,b)와 diethyl succinate와의 Stobbe condensation, 가수분해, 탈수고리화반응으로 이어지는 연속적인 반응을 통하여 성공적으로 합성하였다. 단량체의 화학적 구조를 분광학적 방법으로 분석하여 합성된 단량체 (2a~d)는 (Z,Z)-이성체로 존재함을 확인하였다. 중합은 질소분위기하 150~$210^{\circ}C$의 온도범위에서 괴상중합법으로 행하여졌다. 합성된 고분자의 화학적 구조와 열적 성질을 각각 분광학적 방법과 TGA, DSC를 이용하여 조사하였다. 합성된 고분자의 성질은 곁사슬의 길이에 따른 화학적 구조에 크게 의존함을 알 수 있었다.