• Journal of the Society of Cosmetic Scientists of Korea
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• 제30권2호
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• pp.241-246
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• 2004

To develop novel anti-aging peptides from the germinated black rice, we treated with bromelain, papain and Pronase E. And we investigated the effects of the germinated black rice peptide (GBRP) as anti-aging cosmetic ingredients, and compared with the non-germinated black rice protein (NBRP). We investigated the effects on in vitro inhibition of matrix-metalloprotease (MMP), proliferation of human skin fibroblasts, stimulation of collagen synthesis and expression of UVA-induced MMPs in human skin fibroblasts, UVA induced MMP-1 expression and collagen contents in human skin fibroblasts were analyzed by enzyme-linked immunosorbent assay (ELISA). As a result, the molecular weight distributions of GBRP and NBRP were determined by gel permeation chromatography to be approximately 900 and 10,000 daltons. GBRP increased skin cell proliferation about 40% and reduced UVA-induced MMP-1 expression about 50%. Also the collagen protein level of cells, which were cultured with GBRP, was increased about 25%. These results suggest that the geminated plant seed peptides can be novel anti-aging ingredients for cosmetics.

• Polymer(Korea)
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• 제34권4호
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• pp.294-299
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• 2010

Clay-loaded polypropylene (PP) nanocomposites were fabricated via melt-compounding of two molecular weight ($M_w$) PPs (140 and 410 kg/mol) and octadecylammine-treated clay (C18MMT), with the assistance of maleic anhydride-grafted PP(PP-MAH), respectively, at $170^{\circ}C$ and $190^{\circ}C$. At both melt-compounding temperatures, the low-$M_w$ PP tends to easily diffuse into silicate layers, especially in the presence of the mobile PP-MAH, resulting in a marked increase in silicate layer spacing (above 58 $\AA$), when compared to 27 $\AA$ in the high-$M_w$ PP-based system. Due to relatively lower melt-viscosity of the low-$M_w$ PP-based system, however, there existed quasi-stacked clay aggregates with a thickness of 60~80 nm, while the high-$M_w$ PP-based nanocomposites showed relatively homogeneous dispersion of clays. The different morphologies are mainly related to changes in the viscoelastic properties of PPs, dependent on the processing temperature and their $M_{w}s$. The slight differences in nanocomposites induce discernible crystallization and mechanical behaviors. High-$M_w$ PP-based nanocomposites containing 1~3 wt% C18MMT showed improvement in both tensile strength and modulus, while maintaining the inherent ductility of pure PP.

• Membrane Journal
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• 제10권4호
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• pp.205-212
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• 2000

The true-lPN's based on silicone rubber(SR)rrubbery polymer) and polystyrenc(PS)(glass polymer) were prepared by using the sequential IP!\' method_ The characteristic of permeability of oxygen/nitrogen was investigated with the control of the amount of PSOO-70 wt%) in the true-lPN, As a results of fTlR and N1Vm. the SRIPS membrane was synthesised successfully with the IPN synthetic method, Thermal analysis resulls indicated that the degree of mixing of IPN increased with increase of the amount of PS in the IPN. Regarding the characteristic of gas permeability, the membrane showed a trend of decrease in oxygen permeability as the PS content increased, The oxygen permeability of membrane having 50 wt% of PS. however, increased momentarily, Selectivity, meanwhile, increased slightly as the contents of I'S increased. However, the maximum value of oxygen selectivity, which is 20.6% enhanced Value, was obtained with the membrane containing 50 wt% of PS. This can be explained that the behavior of lPN, i.e. mutual assistance, is pronounced in the membrane having 50 wt% of PS.

• Clean Technology
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• 제7권4호
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• pp.281-290
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• 2001

A microwave-assisted process to prepare chitosan from natural crabshells has been investigated. This study was primarily to examine the effectiveness of microwave as clean energy for chitosan preparation. Several human-edible organic acids were used as clean catalyst, possibly to improve the current HCl-based hydrolysis process of polymeric chitosan. The microwave was found to be effective substantially in reducing the reaction time. Nonetheless, no beneficial effect of microwave other than time, such as the chemical selectivity, was hardly observed. The organic acids were very effective in the hydrolysis reaction of polymeric chitosan. Their catalytic behavior was greatly improved especially when reactions were performed under pressure. In the case of autoclave reaction for 60 minutes at $120^{\circ}C$, viscous solution of polymeric chitosan (mol. wt. > 300,000) turned into thin solutions of water-like viscosity, which means chitosan molecules were decomposed to very small-sized oligomers.

• Applied Chemistry for Engineering
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• 제27권1호
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• pp.26-34
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• 2016

In this study, core-crosslinked amphiphilic polymer (CCAP) nanoparticles prepared using a reactive amphiphilic polymer precursor (RARP) were used for preparing some valuable compounds encapsulated polymer nanoparticles with high payload through nanoprecipitation process. Various solvents (acetone, ethanol, and THF) having different polarity and CCAP nanoparticles prepared using different amphiphilicity were used for the preparation of ${\alpha}$-tocopherol encapsulated polymer nanoparticles to investigate their effects on the encapsulation efficiency, payload, nanoparticle size, and stability. CCAP dissolved in hydrophobic solvent, THF, could form ${\alpha}$-tocopherol encapsulated polymer nanoparticles dispersed in water with the high payload of ${\alpha}$-tocopherol and encapsulation efficiency. Because of their physically and chemically robust nano-structure originated from crosslinking of the hydrophobic core, CCAP nanoparticles could encapsulate ${\alpha}$-tocopherol with the high payload (33 wt%) and encapsulation efficiency (97%), and form 70 nm-sized stable nanoparticles in water.

• Polymer(Korea)
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• 제29권3호
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• pp.300-303
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• 2005

Polyurethane multi-layer and foam multi-layer were prepared with PU1000 and PU2000 made by poly(propylene glycol) (PPG) having the molecular weight of 1000 and 2000 g/mol, respectively. The damping and transmission loss of these materials were compared with PU1000 used as a reference. The damping peak of polyurethane multi-layer was shifted to the lower temperature compared with PU1000, while the damping peak of polyurethane foam multi-layer was shifted to the higher temperature and broaden. In terms of noise reduction, the transmission loss of polyurethane multi-layer was effective at the specific frequency range such as less than 100 Hz and around 600 Hz compared with PU1000. The transmission loss of polyurethane foam multi-layer was most effective in the whole experimental frequency range.

• Polymer(Korea)
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• 제38권2호
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• pp.199-204
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• 2014

To prepare acrylic pressure sensitive adhesives (PSAs), quaternary copolymer syrups were photopolymerized from 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate as default constituents and isobornyl acrylate and tetrahydrofurfuryl acrylate (THFA) as variable constituents. After polymerization, 1,6-hexanediol diacrylate and photoinitiator were added and then crosslinked by UV-irradiation to prepare the PSAs. The characteristics of the syrup such as viscosity, molecular weight, and solid content were investigated. As increasing THFA contents, the relationship between molecular weight and solid content of the syrup was reciprocal. Also, the relationship between peel strength and surface energy of the PSAs showed the same tendency. All the PSA samples showed high transmittance (more than 92%), low haze (less than 1.0%) and low color-difference (less than 1.0).

• Applied Biological Chemistry
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• 제42권2호
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• pp.128-133
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• 1999

To enhance functional properties of 4 different hoki frame protein hydrolysates (30K, 10K, 5K and 1K hydrolysate) fractionated through a series of 30, 10, 5 and 1 kDa molecular weight cut-off membranes in order to decrease pore size, all hydrolysates were phosphorylated with sodium trimetaphosphate and altered phosphorylated 30K, 10K, 5K and 1K (P-30K, P-10K, P-5K and P-1K), respectively. The covalent attachment of anionic phosphate groups to polypeptide chains improved the functional properties, such as solubility, emulsifying properties and foaming properties, of hoki frame protein hydrolysates. Especially, P-30K hydrolysate with the highest molecular weight fraction possessed the most excellent functional properties among 4 different phosphorylated hydrolysates.

• Korean Journal of Food Science and Technology
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• 제32권3호
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• pp.610-617
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• 2000

The indigestible dextrin with high indigestible fraction was prepared by treating the enzyme hydrolysate of pyrodextrin with ethanol or strongly acidic cation exchange resin(UBK 530). Optimum conditions of ethanol treatment for preparing the indigestible dextrin from $\alpha-amylase$ and amyloglucosidase treated hydrolysate were determined based on the indigestible fraction, dietary fiber content, and yield. Ethanol was added 5-fold by weight to 30%(w/w) enzyme hydrolysate, and the mixture was kept at room temperature for 3 hr. Low molecular weight saccharides containing glucose and high molecular weight saccharides were separated by strongly acidic cation exchange resin. While initial enzyme hydrolysate by $\alpha-amylase$ and amyloglucosidase showed 43.6% of DPI(glucose) and 51.1% of DP4+(maltotetraose and over), the indigestible dextrin collected to 50% of initial enzyme hydrolysate by treatment of cation exchange resin showed 7.1% of DPI(glucose) and 91.2% of DP4+(maltotetraose and over). In conclusion, 44.5% of indigestible fraction of initial enzyme hydrolysate increased to 78.9% after separation of low molecular weight saccharides.

• Membrane Journal
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• 제30권4호
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• pp.260-268
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• 2020

Mixed-matrix carbon molecular sieve membranes containing conventional and hierarchically structured 5A were synthesized for application in oxygen (O₂)/nitrogen (N₂) separation. In general, incorporating 5A fillers into porous carbon matrices dramatically increased the permeability of the membrane with a marginal decrease in selectivity, resulting in very attractive O₂/N₂ separation performances. Hierarchical zeolite 5A, which contains both microporous and mesoporous domains, improved the separation performance further, indicating that the mesopores in the zeolite can serve as an additional path for rapid gas diffusion without sacrificing O₂/N₂ selectivity substantially. This facile strategy successfully and cost-effectively pushed the performance close to the Robeson upper bound. It produced high performance membranes based on Matrimid^® 5218 polyimide and zeolite 5A, which are inexpensive commercial products.