• Journal of the Korean Applied Science and Technology
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• v.18 no.4
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• pp.306-315
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• 2001

Our study is aimed at proposal of systematic verification method of molecular structure using measuring method of selective ionic determination and spectrometry on 34 kinds of surfactants such as sodium dodecyl sulfate(SDS) which are most widely used today. In the IR spectrum, unsaturated fatty acids reveal themselves by HC= at $3000{\sim}3020cm^{-1}$, and intensity of $720cm^{-1}$ depends on carbon length of alkyl group. Also ethylene oxide(EO) adducts exhibit weak characteristic bands by $-CH_{2}-CH_{2}-O$ at 1350, 1100 and $950cm^{-1}$. Isethionate can be distinguished from diester succinate by intensity ratio of 1740 and $1200cm^{-1}$ spectrums, the ratio of latter is close to 1 due to 2 carboxylate radical in diester succinate. Quaternary ammonium salts exhibit characteristic band of $C_{4}N^{+}$ at $1000-900㎝^{-1}$. In the case of dialkyl dimethyl ammonium salts in quaternary ammonium surfactants, the spectrum of $3000cm^{-1}$ by $N-CH_{3}$ collapses to a very weak band at $3020cm^{-1}$. In ammonium heterocyclic derivatives, pyridinium salts show characteristic bands at 1640 and $1460cm^{-1}$, while imidazolinium salts exhibit characteristic band at $1620-1610cm^{-1}$. In the characteristic spectrum at $1080-1050cm^{-1}$ on OH radicals of the alkyl esters, primary alcohol appears as weak band and the 2 bands show in almost same intensity when primary and secondary alcohols exist together in one molecule. Also, alkyl ester of polyhydric alcohols appears as various broad band.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.72-72
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• 2018

The root of Angelica gigas Nakai (AGN) is used as a traditional herbal medicine in Korea for the treatment of many diseases. However, a major challenge associated with the usage of the active compounds from AGN is their poor water solubility. Therefore, this work aimed to enhance the solubility of active compounds by a chemical (viz. surfactant) and physical (hot melt extrusion) crosslinking method (CPC). Infrared Fourier transform spectroscopy (FT-IR) revealed multiple peaks in extrudate solids representing new functional groups including carboxylic acid, alkynes and benzene derivatives. Differential scanning calorimetry (DSC) analysis of the extrudate showed lower glass transition temperature (Tg) and lower enthalpy (${\Delta}H$) (Tg: $43^{\circ}C$; ${\Delta}H$: <6 (J/g)) compared to the non-extrudate (Tg $68.5^{\circ}C$; ${\Delta}H$: 123.2) formulations. X-ray powder diffraction (XRD) analysis revealed amorphization of crystal materials in extrudate solid. In addition, nanonization, enhanced solubility and higher extraction of phenolic compounds were achieved in the extrudate solid. Among the different extrudates, acetic acid- and Span 80-mediated formulations showed superior extractions. We conclude that the CPC method successfully enhanced the production of amorphous nano dispersions from extrudate solid formulations.

• Polymer(Korea)
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• v.38 no.6
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• pp.767-773
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• 2014

Rheological and electrical properties of polystyrene (PS)/carbon nanotube (CNT) nanocomposites via coagulated precipitation were investigated. Chemical modification and surfactant wrapping of CNT to improve the dispersion of CNTs may reduce the intrinsic properties of pristine CNT. To avoid this problem, PS and CNTs were dissolved and dispersed in dimethylformamide and then PS/CNT nanocomposites were prepared by the coagulated precipitation of CNT-dispersed PS solution in water. The coagulated precipitation method was highly effective enhancing the electrical conductivity of nanocomposites. Furthermore, the effect of adding poly(styrene-co-divinylbenzene) crosslinked particles to PS matrix on the rheological and electrical properties was investigated. With the addition of the crosslinked particles, the electrical percolation threshold of CNT reduced to 0.25 wt% and electrical conductivity increased further. It is speculated that CNTs in the volume occupied by crosslinked particles helped electrical pathway formation.

• Journal of Adhesion and Interface
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• v.11 no.3
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• pp.112-119
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• 2010

Poly(methyl methacrylate)/poly(butyl acrylate) PMMA/PBA core-shell composite particles were prepared by the emulsion polymerization of MMA and BA in the presence of different concentration of sodium dodecyl benzene sulfonate (SDBS). The following conclusions are drawn from the measured conversion and particle size distribution, morphology, average molecular weight distribution, observation of film formation and particle formation, glass transition temperature and physical properties of polymerized core-shell composition particles for using adhesive binder. When the concentration of 0.03 wt% surfactant, the conversions of PMMA and PBA core polymerization are excellent as 95.8% for PMMA core and 92.3% for PBA core. Core-shell composite particles are obtained 90.0% for PMMA/PBA core-shell composite particles and 89.0% for PMMA/PBA core-shell composite particles. It is considered that the core and shell particles are polymerized to be confirmed FT-IR spectra and average molecular weight measured with a GPC, formation of the composite particles is confirmed by the film formation from normal temperature, and composition of inside and outside of the composite particle is confirmed by TEM photograph. The synthesized polymer has two glass transition temperatures, suggesting that the polymer is composed of core polymer and shell polymer unlike general copolymers. It is considered that each core-shell composite particle can be used as a high functionality adhesion binder by the measurement of tensile strength and elongation.

• YAKHAK HOEJI
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• v.37 no.4
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• pp.370-382
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• 1993

In order for formulation of rectal containing OMZ, the OMZ suppositories were prepared using water-soluble base, PEG 4000 base and oil-soluble base, Witepsol H 15. Chemical stability of OMZ in suppositories was increased when Witepsol H 15 was used as a suppository base and arginine was added as a stabilizer. The decomposition of OMZ in suppository bases followed the first-order kinetics and their rate constants were 0.11 day $^{1}(t_{1/2}$=/6.25 days) for Witepsol H 15 suppository and 0.48 day $^{1}(t_{1/2}$=/1.43 days) for PEG 4000 suppository, respectively. On the other hand, the decomposition rate constants of Witepsol suppository and PEG suppository stabilized with arginine were 3.89$\times$10$^{-3}$(t$_{1/2}$=171.1 days) and 8.76$\times$10$^{-3}$ day $^{1}(t_{1/2}=79.9 days), respectively. Shelf-lives of the Witepsol and PEG suppositories stabilized with arginine were t$_{90%}$=291.8 days and t$_{90%}$=282.1 days at $35^{\circ}C$ and 75% RH, respectively. The dissolution test of OMZ suppositories was performed by rotating dialysis cell(RDC) method and the release rate constant was calculated by the simplified Higuchi's equation, Q'=K' t$^{1/2}$. Dissolution of OMZ from suppositories was augmented as arginine was added, particle size of OMZ was reduced and a suitable surfactant such as SLS was added. RDC method was more appropriate and available than Paddle method to evaluate the dissolution rate of lipophilic-base suppositoies. Arginine was found to be a very useful exipient for the enhancement of stability and dissolution of OMZ in suppositories.

• Journal of the Korean Institute of Gas
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• v.8 no.4 s.25
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• pp.23-29
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• 2004

This work carried out experiment to change characteristics of hydrate formation using various chemicals which are acetone, dimethylbutane, polyvinylalcohol, methanol and ethlyene glycol as additives in gas hydrate formation. Gas storage ability of formed hydrate with acetone, firnethylbuthane and polyvinylalcohol in gas hydrate formation increased higher than that obtained with pure water. Among them polyvinylalcohol showed best gas storage ability, so it is a more useful promoter Methanol and Ethylene gl?col in using additives showed the characteristics of inhibitor and methanol is lower gas storage ability than ethylene gl)rcol as a inhibitor in hydrate formation, so it is a more useful inhibitor. But, low concentration of methanol and ethylene glycol showed considerably higher gas storage ability of hydrate than that obtained with Pure water and showed the characteristics of promoter in gas hydrate formation.

• Applied Biological Chemistry
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• v.50 no.1
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• pp.12-17
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• 2007

A biosurfactant-producing strain, Bacillus subtilis TBM 3101 was isolated from the soil sample at Tae-Baek Mountain through an antifungal test and emulsification assessment. The strain was assessed, regarding to the microbial growth, by physical and chemical test, surface tension, emulsification activity and stability. The surface tension of the isolate sharply decreased to the minimum 29mN/m at 48 h growth. Of note, its emulsification was stabilized to the highest degree when tributyrin was utilized as a substrate, indicating that in comparison to a variety of synthetic surfactants, the biosurfactant produced by the isolate was significantly similar to synthetic surfactant, tween 20. In addition, the biosurfactant showed high emulsification activity when soybean oil, crude oil and tetradecane were used as a substrate. Thus, these studies could contribute to the detection and development of biosurfactant beneficial to the environment and humans.

• Advances in nano research
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• v.15 no.4
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• pp.295-304
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• 2023

In this paper, a powerful photocatalyst based on carbon nanocomposite is developed in order to obtain a new material applicable in water treatment and especially for the discoloration of effluents used in the textile industry. For that, TiO₂-graphene nanocomposites have been successfully synthesized by a mixture of Functionalized Graphene Sheet (FGS) and tetrachlorotitanium complexes to form FGS-TiO₂ nanocomposite. In the presence of an anionic surfactant, we used a new chemical process to functionalize graphene sheets in order to make them an excellent medium for blocking and preventing the aggregation of TiO₂ nanoparticles. The components of these nanocomposites are characterized by means of X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), which confirms the successful formation of the FGS-TiO₂ nanocomposite. It was found that the TiO₂ nanoparticles were dispersed uniformly on the graphene plane which possesses better charge separation capability than pure TiO₂. The FGS-TiO₂ nanocomposites exhibited higher photocatalytic activity compared to pure TiO₂ for the removal of three dyes: such as Methylene Blue (MB), Bromophenol Blue (BB) and Alizarin Red-S (AR) in water. The removal process was fast and more efficient with FGS-TiO₂ nanocomposite in daylight (in the absence of UV irradiation) compared to pure TiO₂ nanoparticles without and under UV in all pH range.

• Korean Chemical Engineering Research
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• v.47 no.5
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• pp.608-614
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• 2009

In this work, ruthenium substituted SBA-15's(Ru-SBA15's) of various Si/Ru ratios were prepared using a non-ionic triblock copolymer surfactant, $EO_{20}PO_{70}EO_{20}$, as template. We investigated the nitrogen or oxygen adsorption/desorption behaviors of the Ru-SBA-15's for their future applications as catalysts or selective adsorbents, etc. The pore size of the Ru-SBA-15's was determined by both the Barrett-Joyner-Halenda(BJH)($D_{BJH}$) and the Broekhoff-de Boer analysis with a Frenkel-Halsey-Hill isotherm(BdB-FFF) method($D_{BdB-FHH}$). The $D_{BJH}$ and $D_{BdB-FHH}$ of the Ru-SBA-15 having 50/1 ratio of Si/Ru were 3.9 nm and 4.7 nm, respectively. The transmission electron microscope(TEM) image of the Ru-SBA 15 of the Si/Ru mole ratio of 50 showed that the pore size is 4.7 nm, which is consistent with the $N_2$ adsorption results with the BdB-FHH method. The surface area of pores form oxygen adsorption/desorption isotherm was higher than that from the nitrogen adsorption/desorption isotherm by the Brunauer-Emmett-Teller(BET) method, which were respectively $612.7m^2/g$, and $573.3m^2/g$. X-ray diffraction(XRD) patterns and TEM analyses showed that the mesoporous materials possess well-ordered hexagonal arrays.

• Journal of the Korean Applied Science and Technology
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• v.34 no.1
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• pp.152-162
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• 2017

A hydrophilic coating solution was prepared by adding a silane coupling agent and a nano-inorganic oxide in aqueous surfactant solution to increase the efficiency of photovoltaic power generation due to the introduction of antifogging and antifouling properties on the glass surface of the solar cell module. Addition of $Ludox^{(R)}$, a nano-inorganic oxide, to 1% hydrophilic coating solution showed improved hydrophilicity and excellent antifogging effect regardless of $Ludox^{(R)}$ concentration. However, the antifouling effect on the glass surface was showed only when Ludox was added more than 10%. In the case of addition of 0.7% of hydrolyzed TEOS at pH 4, the antifogging effect was maintained as a result of the steam test as well as the antifouling effect even after the coated glass surface was rubbed 100 times with a wet Kimwipe. In addition, from the surface roughness ($R_q$) calculated using AFM data, the higher surface roughness with irregular surface shape was obtained with the higher concentration of TEOS. The addition of 0.7% of TEOS showed relatively high surface roughness and well organized surface condition which can help to improve transmittance of light. In conclusion, $Ludox^{(R)}$ is not required only for the antifogging property. However, at least 10% of Ludox should be added to show antifouling effect and 0.7% of TEOS should be added for good durability.