• Journal of Conservation Science
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• 제27권2호
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• pp.201-209
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• 2011

While consolidants based on tetraethoxysilane (TEOS) have been widely used for the consolidation of decaying stone heritages, TEOS-based consolidants suffer from practical drawbacks, such as crack formation of the gel during the drying phase due to the developed capillary force. We have prepared new TEOS-based consolidants containing flexible (3-glycidoxypropyl) trimethoxysilane (GPTMS) in order to reduce capillary force development during gel drying. In this study, we have prepared TEOS/GPTMS-based consolidants containing ETEOS in order to improve the surface hydrophobisity. The physical properties of the TEOS/GPTMS/ETEOS solution with different hydrolysis were compared with those of the commercial products Wacker OH$^{(R)}$. The contact angle of the surface increased with the addition of the ETEOS, which is higher than that of Wacker OH$^{(R)}$. The sol-gel mechanism was manipulated by the degree of hydrolysis as well as the amount of ETEOS. The properties and the applicability of the developed consolidants for the decayed Korean granites are also investigated.

• Journal of the Korean Applied Science and Technology
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• 제35권2호
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• pp.367-377
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• 2018

Swimming crab(Ovalipes punctatus) is produced in Korea and utilized as semi-processed food at streamed cooked state. Recently, protein hydrolysates have been known as having function such as antioxidant, suppression of hypertension, immunodulatory, alleviation of pain, and antimicrobial activity. This research was investigated to find the functional antioxidant from crab hydrolysates. To fine optimal protease enzyme, alcalase, bromelain, flavourzyme, neutrase, papain, and protamex were selected to evaluate the DPPH radical scavenging activity and finally bromelain to show the best activity was selected. The molecular weight of bromelain hydrolysates were distributed with range from 500 to 3,200 Da and 7 different molecules or more. The amino acids related to antioxidant capacity was about 42.54%. The processes optimization study used was the response surface methodology. The ranges of processes were the reaction temperature of 40 to $60^{\circ}C$, pH 6 to 8, and enzyme concentration 1 to 3%(w/v). As a result, the optimization of process was determined at temperature of $55^{\circ}C$, pH of 6.5, and enzyme concentration of 3%(w/v). In these conditions, degree of hydrolysates were maximum 71.60%. Therefore, we expect that those products are useful as functional food ingredients.

• Journal of the Society of Cosmetic Scientists of Korea
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• 제30권2호
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• pp.189-195
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• 2004

Carbon black have not been used as pigment material in cosmetic because of very low density and dispersity, but carbon black have applicable character as black pigment because of non-toxic, stable physico-chemical property, and black colority. In this study, mesoporous silica samples were synthesized by sol-gel reaction using surfactants-template method; TEOS (tetraethoxysilane) - a) PEO/lecithin, b) PEO/polyethylene glycol, c) lecithin/polyethylene glycol in ethanol/water solution. Synthesized organic-inorganic hybrid - silica were heat-treated in N2 condition at 500$^{\circ}C$. Mesoporous silica with black carbon in pore have the effective density and show the good dispersity in both hydrophilic and hydrophobic solvent. Properties of the samples were measured; specific surface area (750㎡/g) and pore size (4-6nm) using BET, pore structure (cylindrical type) using XRD, morphology (spherical powder with 0.1-0.5$\mu\textrm{m}$ partical size) of the samples using SEM. Carbon-silica black color applied to mascara, it shows a dark black colority and good dispersity as compared with the general black color titania pigment. Moreover, it is possible to control the density of black color pigment because it is possible to control pore volume and particle size of mesoporous silica properly. It show the good volume effects in mascara. That is why possible to apply all kinds of cosmetic products.

• Applied Chemistry for Engineering
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• 제22권2호
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• pp.173-177
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• 2011

In this study, the formation of $AlPO_4$-type porous materials from alum sludge was investigated. The materials were synthesized by the reaction of aluminum hydroxide and phosphoric acid with an organic template. Cationic surfactant, natural humic acid, and amino acids were used for the organic template. The residual organic templates were removed by calcination at $600^{\circ}C$ in the air. Powder X-ray diffraction patterns showed the charicteristic patterns of the $AlPO_4$-type porous materials. The morphology of the material was examined using a scanning electron microscopy. The coordination environment of $Al^{3+}$ ion was investigated by $^{27}Al$ MAS NMR technique. Both tetrahedrally and octahedrally coordinated$Al^{3+}$ ions were found in the as-synthesized samples while all $Al^{3+}$ ions were tetrahedrally coordinated in the calcined products. The development of mesopore in the solid material was confirmed by the measurement of BET specific surface area. Finally, they were used for removal of toxic formaldehyde from the air and the formaldehyde molecules were adsorbed on the surface of pores. In conclusion, $AlPO_4$-type porous materials from alum sludge might be applicable in the removal of toxic volatile organic compounds from the air.

• Korean Chemical Engineering Research
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• 제49권3호
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• pp.330-337
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• 2011

In this research, the preparation processes for making a series of $\omega$-mercapto alkylamine 1 and $\omega$-mercapto alkanoic acid 2 useful for studying of the self-assembled monolayer(SAM) are described. The preparation methods of the first goal materials, $\omega$-mercapto alkylamines 1 were carried out as follows: First, $\omega$-phthalimide alkanol 3 was synthesized from commercially available potassium phthalimide derivatives and $\omega$-bromoalkanol in DMF at $80{^{\circ}C}$ via substitution reaction. After refluxing $\omega$-phthalimide alkanol 3 with hydrazine hydrate in ethanol followed by treating with c-HCl, $\omega$-aminoalkanol 4 was obtained in 76-98% yield, accompanied with side-product 5. Bromination of hydroxyl moiety of $\omega$-aminoalkanol 4 using aqueous hydrobromic acid furnished $\omega$-bromoamine 6 in 34-97% yields. Substitution reaction 6 with thiourea in 95% ethanol gave $\omega$-aminoalkanthiuronium 7, which was treated with aqueous strong base and aqueous strong sulfuric acid gave desired products, $\omega$-mercapto alkylamines 1 through overall 5 steps. The second target material, $\omega$-mercapto alkanoic acid 2 was prepared via 2 steps. $\omega$-bromo alkanoic acid was reacted with thiourea to give $\omega$-thiourea alkanoic acid 7 in 69-85%, which was treated with aqueous strong base and strong acid to furnish $\omega$-mercapto alkanoic acid 2 in 50-98%. The fabricated long-chain alkylthiol(LCAT) can be used as linkers to immobilize protein, enzyme and various kinds of biomolecules on the surface of metallic materials(Au, Pt, Ti) by SAM, and can be useful chemical tools for the application study on the surface modification of metallic materials.

• Journal of Korean Society of Environmental Engineers
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• 제31권1호
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• pp.1-8
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• 2009

This research was performed to assess a Fenton-like oxidation using naturally present iron in the field to treat remained oils throughout silty clay residues which finally resided even after a series of soil washing process. Biodegradability was thus tested for reaction products to investigate a possible treatment of the Fenton-like oxidation coupled with a biological treatment process. For those purposes, two types of field soil samples (e.g., dewatered cake after conditioning with a polymer and not-dewatered residue) were tested to remove TPH by adding the various concentration of hydrogen peroxide ($H_2O_2$). Moreover the biodegradability of treated samples was observed based on the ratio of $BOD_5/COD_{Cr}$ after Fenton-like oxidation. The Highest removal of TPH was at 1% of hydrogen peroxide ($H_2O_2$) when hydrogen peroxide ($H_2O_2$) was continuously injected for a period of time rather than that of spot introduction with the same amount of it. For the dewatered cake, TPH was effectively treated when the ratio of solid and water was mixed at 1 : 2. Employing cooking oil could increase solubility of TPH due to enhanced surface-active escalating TPH desorption from silty clay. Nonetheless, the biodegradability was decreased as long as the oxidation duration being extended regardless of operational conditions. It was therefore proved that Fenton-like oxidation using $H_2O_2$ and natural iron minerals was able to remove adsorbed oils in silty clay but the removal efficiency of TPH was low. And if a biological treatment process followed after Fenton-like oxidation, microorganisms would need enough time for acclimation.

• Journal of the Korean Applied Science and Technology
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• 제34권2호
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• pp.338-348
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• 2017

Protein hydrolysates derived from plants and animals having antioxidant, suppression of hypertension, immunodulatory, alleviation of pain, and antimicrobial activity has been known as playing important role like hormone. This study was performed to optimize the hydrolysis of protein of sea of cucumber by a flavourzyme. The ranges of processes were the reaction temperature of 40 to $60^{\circ}C$, pH 6 to 8, and enzyme concentration 0.5 to 1.5%(w/v). As a result, the optimization of process was determined at temperature of $48-50^{\circ}C$, pH of 7.0-7.2, and enzyme concentration of 1.0-1.1%(w/v), and degree of hydrolysis was 43-45 at above conditions. The molecular weight of hydrolysate was distributed to 500-3,500 Da and showed typical peptides. Inhibition concentration ($IC_{50}$) of peptides of DPPH radical scavenging activity, Superoxide anion radical scavenging activity, Hydroxy radical scavenging activity, $Fe^{2+}$ cheating activity was 1.25, 3.40, 10.3, and 22.11 mg/mL, respectively. Therefore, we expect that those products are useful as functional food ingredients.

• Korean Journal of Materials Research
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• 제4권6호
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• pp.669-680
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• 1994

Oxidation behaviour of TiAl intermetallic compounds with the addition of Cr, V, Si, Mo, or Nb was investigated at 900~$1100^{\circ}C$ under the atmospheric environment. The reaction products were examined by XRD, SEM equipped with WDX. The weight gain by continuous oxidation increased with the addition of Cr or V, but there was less weight gain when Mo, Si or Nb was added individually. he oxidation rate of Cr- or V-added TiAl was always larger than that of TiAI. However, oxidation rate of Si-, Mo- or Nb-added TiAl was almost same or smaller than that of TiAI. Thus, it is concluded that the addition of Cr or V did not improve the oxidation resistance, whereas the addition of Si, Mo or Nb improved the oxidation resistance. Oxides formed on TiAl with Mo, Si, and Nb were found to be more protective, resulting from the decrease in diffusion rate of the alloying elements and oxygen. Nb strengthened the tendency to form $AI_{2}O_{3}$ in the early stage of oxidation, due to the continuous $AI_{2}O_{3}$ layer formation and dense $Tio_{2}+AI_{2}O_{3}$ layer. According to the Pt-marker test of TiAI- 5wt%Nb, oxygen diffused mainly inward while oxides were formed on the substrate surface. Upon thermal cyclic oxidation at $900^{\circ}C$, it is shown that the addition of Cr or Nb improved the adherence of oxide scale to the substrate.

• Polymer(Korea)
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• 제29권2호
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• pp.177-182
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• 2005

Montmorillonite (MMT) modified with siloxane diamine was reacted with a reactant obtained from 4,4'-diphenyl methane diisocyanate (MDI) and polyester type polyol, $Nippollan4010(\bar{M}_n2000)$. Finally, polyurethane (PU)/MMT composites were prepared by using 1,4-butane diol as a chain extender in $25\;wt\%$ solution of N,N-dimethyl acetamide (DMAc). It was expected that these nanocomposites had superior exfoliation property to that of MMT dispersed polyurethanes produced by simple mixing due to insertion of siloxane main chain to the silicate interlayer of MMT. Extent of reaction and formation of final products were analysed by using FT-IR spectroscopy. Dispersion into the PU and intercalation of MMT were identified by applying X-ray diffraction (XRD) and transmission electron microscopy (TEM). Tensile data were acquired by universal test machine (UTM). Thermal stability and variation of surface energy were characterized by thermal gravimetric analysis (TGA) method and measurement of contact angle on the synthesized composites, respectively. As the results the organo-MMT modified with siloxane diamine in the PU composites has an intercalated structure relatively well-expanded rather than a completely exfoliated structure. The tensile strengths and the moduli for the PU/organo-MMT composites were drastically enhanced in comparison to those of $PU/Na^+-MMT$ composites.

• Journal of the Korea Concrete Institute
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• 제21권1호
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• pp.3-11
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• 2009

The increased demand and consumption of coal has intensified problems associated with disposal of solid waste generated in utilization of coal. Major utilization of coal by-products has been in construction-related applications. Since fly ash accounts for the part of the production of utility waste, the majority of scientific investigations have focused on its utilization in a multitude of use, while little attention has been directed to the use of bottom ash. As a consequence of this neglect, a large amount of bottom ash has been stockpiled. However, the need to obtain safe and economical solution for its proper utilization has been more urgent. The study presented herein is designed to ascertain the performance characteristics of bottom ash, as autoclaved lightweight foamed concrete product. The laboratory test results indicated that tobermorite was generated when bottom ash was used as materials for hydro-thermal reaction. According to the analysis of variance, at the fresh state, water ratio affects on flow and slurry density of autoclaved lightweight foamed concrete, but foam ratio influences on slurry density, while, at the hardened state, foam ratio affects on the density of dry and the compressive strength but doesn't affect on flexural and tensile strength. In the results of response surface analysis, to obtain target performance, the most suitable mix condition for lightweight foamed concrete using bottom ash was water ratio of 70$\sim$80% and foaming ratio of 90$\sim$100%.