• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1188-1192
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• 2004

Polyamic acid precursors were prepared by mixing various main chain dianhydrides, main chain diamines and side chain diamines. Copolyimide films with alkylcyclohexylbenzene as a side chain were prepared by thermal imidization of polyamic acid precursors. Pretilt angles on rubbed polyimides changed according to the side chain and main chain structures of the polyimide. Consequently, we found that LC pretilt angles of polyimide films with a liquid crystal structure as a side chain showed to be approximately 90$^{\circ}$ when a linear and rigid polyimide main chain and a side chain of suitable length were employed.

• Polymer(Korea)
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• v.30 no.1
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• pp.56-63
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• 2006

We have synthesized two types of diamine monomers containing various chain length to prepare polyimides with layered structure. By using these diamines, homo-polyimides and co-polyimides having hydrophobic and hydrophilic segment of flexible side chain were synthesized. The segregated layered structures were formed by repulsive force with main chain as the side chains reach a critical length because the rigid main chains are packed into layered structure with the flexible side chains occupying the space between layers. As a result, the gallery space of each homo-polyimide was increased at spacing of $32.7\~48{\AA}\;or\;7\~10.5{\AA}$ as the increased hydrophobic or hydrophilic side chain length through X-ray diffraction. The gallery space of co-polyimides was also showed similar phenomenon by repulsive force of side chains with different properties. We have also confirmed that gallery space and molar volume were significantly depended on length of flexible side chain via molecular modeling.

• Applied Chemistry for Engineering
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• v.10 no.5
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• pp.743-747
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• 1999

The component polymer was modified to enable the formation of intermolecular hydrogen bonding in the immiscibile polystyrene(PS)/polymethacrylate(PMA) blends. The mole percentages of hydroxystyrene of the poly(styrene-co-4-hydroxystyrene) copolymer(modified polystyrene, MPS) were controlled to 7%, 10% and 18%, respectively. MPS was used with PMA to study the variation of the miscibility in blends. PMA which had such different length of side chain as methyl, butyl, hexyl and ethylhexyl, respectively, was selected to study the effect of side chain length on the formation of intermolecular hydrogen bonding. As the hydroxyl content of MPS increased, the formation of intermolecular hydrogen bonding increased. The length of side chain of PMA had enormous effect on the miscibility of blend as confirmed from the result of cloud point measurement. As the length of side chain increased, the formation and the strength of intermolecular hydrogen bonding decreased severely due to the steric effect and the increased chain mobility.

• Macromolecular Research
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• v.16 no.4
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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.

• Food Science and Biotechnology
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• v.17 no.1
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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.

• Polymer(Korea)
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• v.26 no.4
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• pp.439-444
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• 2002

Several monomeric benzilidene anhydrides (2a~d) haying n-alkyloxy groups with various n-alkyl chain lengths were prepared by Stobbe condensation of diethyl succinate with 4-(n-alkyloxy)benzaldehyde (1a,b) followed by hydrolysis by the succinates and cyclodehydration of the benzilidenated succinic acids. Configurational isomerism of the monomer was investigated by spectroscopic means. It was found that monomers (2a~d) exist in (Z,Z)-isomeric structure. Polymerization was carried out in bulk at 150~$210^{\circ}C$ range in nitrogen flow. The chemical structure and thermal properties of the polymers were characterized by spectroscopic means, TGA and DSC. Their properties highly depended on their chemical structures in accordance with a side chain length.

• Journal of Distribution Research
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• v.7 no.1
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• pp.41-59
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• 2002

Analysis about supply chain structure was achieved in product unit that is not 'business' dimension that is existent discussion target in surrounding and supply chain structure as that this study analyzes positively how supply chain structure according to business surroundings of product changes. This can do that analysis of product unit in synthetic supply chain management is essential when recognize the importance that supply chain management must consist by product special quality according to corporation's each product. Sort product environment and studied relation with supply chain structure to achieve study purpose hereupon. Structure variable of supply chain drew through existent literature study here. Executed question investigation for supply chain by product for study that is actual proof enemy, and figure method used analysis of variance (ANOVA) mainly. If summarize result of study, result that analyze relation between business environment of product and supply chain structure, according to business environment of product, showed that supply chain structure changes. Certified that relation of two group (environment group of uncertain product and environment group of stable product) of business environment of product and structure variable (that is number of participant of supply chain, lead time of supply chain, about administration's independence, response points of supply chain) of supply chain is significant relation all from all structure variables except number of participant of supply chain. Variable that express length of supply chain from structure Variable of supply chain is number of participant of supply chain and lead time of supply chain, and variable that display monitoring or trust aspect for supply chain is administration's independence degree and response points of supply chain. As analysis result, product that environment is uncertain is appearing more shortly than product that length of supply chain stabilizes, and also, monitoring or trust aspect for supply chain was proved that is consisting abuzzer than product that stabilize. Therefore, showed that put essential point in administration of 'hierarchy'putting first than 'market' when business environment designs supply chain structure in case of uncertain product, and proved that the other side business environment is focusing in administration way of 'market' putting first in case of stable product.

• Polymer(Korea)
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• v.25 no.2
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• pp.279-292
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• 2001

Two kinds of (hydroxypropyl)cellulose(HPCs) with different molar substitution (MS) and three types of derivatives based on the HPCs: (acetoxypropyl)celluloses, (ethoxypropyl)celluloses, and (cyanoethoxyprofyl)celluloses were synthesized, and their thermal and mesomorphic properties were investigated. All samples, which exhibit cholesteric reflection colours at room temperature, formed right-handed helicoidal structures whose optical pitches (λ$_{ms}$ ) increase with temperature. However, the isotropization ($T_{i}$) and glass temperatures, the magnitude of λ$_{m}$ of the mesophase at the same temperature, and the temperature dependence of λ$_{m}$ of the investigated derivatives highly depended on MS and the length and structure of the side chain introduced in HPC. The results were discussed in terms of the difference in the polarity and flexibility of the substituents and the distance between the main chains. For all derivatives, Am values approached infinity at temperatures above the $T_{i}$, of the mesophase, and no reversal in the sense of the pitch with temperature was detected.

• Macromolecular Research
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• v.15 no.2
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• pp.185-190
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• 2007

Poly(norbornene dimethyl dicarboxylate)s, (PNDMD)s, were prepared by addition polymerization with palladium(II) catalyst from pure exo-monomers, and their structure and properties were compared with those of poly(norbornene dicarboxylic acid dialkyl ester)s, (PNDADA)s. Both polymer series exhibited good solubility in general organic solvents and excellent thermal stability up to $330^{\circ}C$. Wide-angle X-ray scattering (WAXS) study indicated the presence of nano-scale layer-like order in amorphous PNDADAs, while PNDMDs showed random amorphous structure. The glass transition temperatures and dielectric constants of solid polymers were found to decrease as the alkyl side-chain length increases for both polymer series. However, PNDMDs showed lower glass transition temperatures and higher dielectric constants, as compared with those of PNDADAs containing the same alkyl substituents. This difference, caused by the higher side-group mobility of PNDMDs, may be closely related to the nano-scale order in amorphous PNDADAs and its absence in PNDMDs.

• Microbiology and Biotechnology Letters
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• v.46 no.1
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• pp.29-39
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• 2018

Vibrio vulnificus needs various responsive mechanisms to survive and transmit successfully in alternative niches of human and marine environments, and to ensure the acquisition of steady energy supply to facilitate such unique life style. The bacterium had genetic constitution very different from that of Escherichia coli regarding metabolism of glycogen, a major energy reserve. V. vulnificus accumulated more glycogen than other bacteria and at various levels according to culture medium and carbon source supplied in excess. Glycogen was accumulated to the highest level in Luria-Bertani (3.08 mg/mg protein) and heart infusion (4.30 mg/mg protein) complex media supplemented with 1% (w/v) maltodextrin at 3 h into the stationary phase. Regarding effect of carbon source, more glycogen was accumulated when maltodextrin (2.34 mg/mg protein) was added than when glucose or maltose (0.78.1-14 mg/mg protein) was added as an excessive carbon source to M9 minimal medium, suggesting that maltodextrin metabolism might affect glycogen metabolism very closely. These results were supported by the analysis using the malP (encoding a maltodextrin phosphorylase) and malQ (encoding a 4-${\alpha}$-glucanotransferase) mutants, which accumulated much less glycogen than wild type when either glucose or maltodextrin was supplied as an excessive carbon source, but at different levels (3.1-80.3% of wild type glycogen). Therefore, multiple pathways for glycogen metabolism were likely to function in V. vulnificus and that responding to maltodextrin might be more efficient in synthesizing glycogen. All of the glycogen samples from 3 V. vulnificus strains under various conditions showed a narrow side chain length distribution with short chains (G4-G6) as major ones. Not only the comparatively large accumulation volume but also the structure of glycogen in V. vulnificus, compared to other bacteria, may explain durability of the bacterium in external environment.