• Polymer(Korea)
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• v.24 no.6
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• pp.794-801
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• 2000

The effect of chain length and packing density of intercalated surfactants, annealing temperature, and annealing time on static melt intercalation of thermoplastic polymers was examined using x-ray and FTIR spectroscopy. Although melt intercalation of polymers was not successful when alkyl chains in organosilicates form a lateral monolayer structure, the type and structure of surfactants could not much affect final interlayer distances of most polymer/silicate hybrids. As annealing time increases, interlayer distance in organosilicates increases while the dispersity of the spacing between silicate layers decreases. However, the dispersity of interlayer spacing as well as interlayer distance in organosilicates increase with annealing temperature.

• Textile Coloration and Finishing
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• v.7 no.2
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• pp.40-46
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• 1995

In order to study the dyeability of wool S-cyano ethylated wool-keratine(SCEK) as a model compound of wool was prepared from the reaction of reduced merino wool fiber and acrylonitrile. The binding of acid dyes(methyl orange and it's homologs) by SCEK over the temperature 60~9$0^{\circ}C$ were investigated. The first binding constants and the thermodynamic parameters in the course of the binding were evaluated. It was found that at the 60~9$0^{\circ}C$ range complex formation between the dye and SCEK is associated with an exothermic enthalpy change and a positive entropy change. The enthalpy and entropy changes of the binding are of the order of -4.5 kcal/mole and 8.5 eu, respectively, for each dye measured. Thus the binding is mainly enthalpy-controlled. Furthermore the effect of the alkyl chain length of the dye on both the ΔH$^{\circ}$and ΔS$^{\circ}$value is not prounced. Also temperature dependences of the ΔH$^{\circ}$and ΔS$^{\circ}$values were not obserbed.

• Applied Chemistry for Engineering
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• v.3 no.2
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• pp.273-279
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• 1992

Polymerized vesicles were prepared from monomeric cholesterol-containing surfactant. These vesicles were used to extract the free cholesterol. A polymerized vesicle was formed both monomeric cholesterol-containing surfactant and monomeric surfactant containing two alkyl chain(50 : 50 weight ratio). This vesicle got the better extracting capacity compared with the vesicle which got the other weight ratio of the surfactants. This vesicle also exhibited the fastest substrate permeability. These all results showed that considerable vacant room is necessary in polymerized vesicles in order to extract more cholesterols.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.2
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• pp.178-182
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• 1998

Previously, we showed that acetone enhanced aryl hydrocarbon hydroxylase (AHH) activity in only 3-methylcholanthrene (MC)- or $\beta$-naphtoflavone (BNF)-inducible microsomes of rat liver. In the present study, the possible mechanism underlying acetone action on AHH was investigated in the liver microsomes from MC-pretreated rats. Other n-alkylketones except acetone did not increase AHH activity, which rather decreased significantly with the length of alkyl side chain. Acetone had no effect on the activity of NADPH-cytochrome P450 reductase or inhibited the formation of 3-OH benzo(a)pyrene (B(a)P) in nonenzymatic model ascorbic acid system. However, in cumene hydroperoxide (CuOOH)-supported B(a)P hydroxylation, acetone enhanced its velocity remarkably by 30% at the optimal concentration (30 $\mu$M CuOOH and 1.0% acetone). From these results, we conclude that acetone may facilitate the formation of an activated oxygen species or the insertion of oxygen into B(a)P molecule in CYP1A rich microsomes.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.286-290
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• 2006

New quaternary ammonium chlorides, [alkyldimethyl-[5-(2-phenylthiazol-4-yl]-1,3,4-oxadizol-2-ylmethyl]quaternary ammonium chlorides (ADOQACs): 6] were obtained with high yields by the reaction of compound 5 with N,N-dimethylalkyl amines in isopropyl alcohol. The structures and physical properties of the synthesized compounds were investigated and those surface-active properties were measured. The surface tension ($\gamma_{cmc}$) and the minimal inhibitory concentration (MIC) of compound 6 were found to be influenced by the number of alkyl chain carbon. Especially, compounds 6c and 6d exhibited high anti-bacterial activities and good surface-active properties.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.281-286
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• 1999

The conducting composites were prepared by blending polypyrrole (PPy) as a conducting polymer and nylon6,6 as a matrix. In chemical polymerization of PPy, the oxidizing agent was $FeCl_3$ and dopant was alkylbenzenesulfonic acid, such as camphorsulfonic acid (CSA) or dodecylbenzene sulfonic acid (DBSA). The electrical conductivity and mechanical properties were measured for the amount of dopant and PPy complex, and these morphology observed. When it was doped with DBSA having long alkyl chain and added the PPy complex of 25 wt %, the electrical conductivity was increased up to 0.64 S/cm.

• Journal of Hydrogen and New Energy
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• v.28 no.5
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• pp.584-599
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• 2017

Biodiesel is renewable, eco-friendly, clean burning diesel replacement that is consisted of short chain alkyl ester. Biodiesel is derived from the transesterification of vegetables oils or animal fats with alcohol. The process has some technical problems that must be resolved to reduce the high operation cost. Eco-friendly physical technologies by using microwave have successfully improved the transesterification for biodiesel production. This paper attempts to extensively review microwave-assisted technology for biodiesel production. Additionally, different types of catalyst for biodiesel production have been summarized. It is concluded that the microwave-assisted technique improves the reaction rate significantly in comparison with conventional methods. Therefore it can be a suitable method of reducing the reaction time and can also decreases the cost of biodiesel production.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.4
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• pp.318-325
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• 2000

Dynamic behaviors of saturated-fatty acids $C_{16}$, $C_{18}$, $C_{20}$ and 8A5H with azobenzene were measured by displacement current method when the molecules are stimulated by pressure light and heat. When a barrier was compressed I-A, $\pi$-A isotherms of $C_{16}$, $C_{18}$, and $C_{20}$ were similar to each other but the displacement current of $C_{20}$ which has a long alkyl chain was relatively low. 8A5H showed the form of double liquid films and had a reversible reaction when a barrier was compressed and then expanded. When the molecules of 8A5H were stimulated by 365[nm] light the positive currents which were generated by the structural changes from trans to cis were measured. But the negative currents of the structural changes from cis to trans by 450[nm] light were too weak to detect. When the temperature of the water subphase was increased the surface pressures of the monolayers were increased early because of the thermal activations of the molecules and the double liquid films of 8A5H were disappeared above 40[$^{\circ}C$]EX>].

• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.545-551
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• 2010

Hydrophobically monoendcapped poly(sodium acrylate)s formed hydrophobic microdomains in water. This was concluded on poly(sodium acrylate)s with a linear $C_{12}$-alkyl chain attached specifically at the end of the polymer. There was no well defined CMC (critical micelle concentration), but rather a gradual transition from a micelle free solution to a micelle solution. Steady state fluorescence spectroscopy indicates that the micro domains are rather hydrophobic. At pH 5 in the abscence of salt and at pH 9 in the prescence of 1 M sodium citrate the CAC (critical aggregation concentration) was in the range of 0.1 to 2.4 mM. However at pH 5 there was a linear increase in the transition concentration with a head-group size due to an increase in steric and electrostatic repulsions between polymer main chains. At pH 9 in the abscence of salt the transition concentration was in the range of 1 to 80 mM. For the larger polymers there was a effect which consisted of a concentration gradient of sodium counterion toward the hydrophobic domain. The effect was larger for the larger polymers because of the higher total sodium concentration and the less steep counterion concentration gradient.

• Bulletin of the Korean Chemical Society
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• v.24 no.12
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• pp.1793-1798
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• 2003

A series of amorphous molecules that possess both photoconductive and electro-optic properties was synthesized in order to investigate photorefractive properties of bifunctional organic-glasses. Diethylaminobenzaldehyde-diphenylhydrazone was covalently attached to 5-(4-diethylamino-benzylidene)-1,3-dimethylpyrimidine-2,4,6-trione through a flexible alkyl chain (3, 4, 5, 6 and 10 carbons) containing two ether linkages. The longer linkage not only lowered the glass transition temperature ($T_g$) of the molecules, but also allowed faster orientation of the chromophore. To examine the photorefractive properties, a 50 ${\mu}$m-thick film was prepared from the mixture of a bifunctional molecule, butyl benzyl phthalate, and $C_{60}$. The photoconductivity of this composite was as high as $8.01\;{\times}\;10^{-12}$ S/cm at 60 V/ ${\mu}$m, and the maximum diffraction efficiency ( ${\eta}_{max}$) of 50 ${\mu}$m-thick film was about 5% at 80 V/ ${\mu}$m.