• 한국포장학회:학술대회논문집
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• 2006.11a
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• pp.54-73
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• 2006

Four different types of chitosan-based nanocomposite films were prepared using a solvent casting method by incorporating with four types of nanoparticles, i.e., an unmodified montmorillonite (Na-MMT), an organically modified montmorillonite (Cloisite 30B), a Nano-silver, and a Ag-zeolite (Ag-Ion). X-ray diffraction patterns of the nanocomposite films indicated that a certain degree of intercalation was formed in the nanocomposite films, with the highest intercalation in the Na-MMT-incorporated films followed by films with Cloisite 30B and Ag-Ion. SEM micrographs showed that in all the nanocomposite films, except the Nanosilver-incorporated one, nanoparticles were dispersed homogeneously throughout the chitosan polymer matrix. Consequently, mechanical and barrier properties of chitosan films were affected through intercalation of nanoparticles, i.e., tensile strength (TS) increased by 7-16%, while water vapor permeability (WVP) decreased by 25-30% depending on the nanoparticle material tested. In addition, chitosan-based nanocomposite films, especially silver-containing ones, showed a promising range of antimicrobial activity.

• Korean Journal of Food Science and Technology
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• v.36 no.3
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• pp.432-439
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• 2004

Increase in water vapor barrier properties of sodium alginate films was studied by preparing composite films with fatty acids, i.e., lauric, palmitic, stearic, and oleic acids, and by treatment with 3% $CaCl_{2}$ solution for 3 min. Film thickness, surface color, microstructure, tensile strength (TS), elongation at break (E), water vapor permeability (WVP), water solubility (WS), and sorption isotherm of films were investigated. Microstructure of films observed with SEM was changed by fatty acid and $CaCl_{2}$ treatments. TS decreased 25-70% depending on fatty acid used, and increased 1.5- to 2-fold by $CaCl_{2}$ treatment. E decreased by both fatty acid and $CaCl_{2}$ treatments. Except oleic acid, WVP decreased significantly (p<0.05) by forming composite films with fatty acids, particularly with stearic acid, WVP decreased more than two-fold. WS also decreased by fatty acid and $CaCl_{2}$ treatments. In stearic acid, WS decreased about 30-fold by combined treatment of fatty acid and $CaCl_{2}$. Sorption isotherm showed typical biphasic pattern with deliquescent point of 0.75. Results of isotherms and BET monolayer moisture content indicated hydrophilicity of film decreased by $CaCl_{2}$ treatment.

• Applied Biological Chemistry
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• v.50 no.2
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• pp.111-115
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• 2007

To modify the physical properties of alginate film, the gamma ray irradiation was performed, and alginate film properties such as elongation strength (ES), elongation rate (ER), water vapor permeability(WVP), and water solubility (WS) were measured. The film made from 1.75% alginate solution (w/w) with the addition of 2% CaCl$_2$ solution suggested a good application for a film preparation in that elongation strength(ES) increased 5 fold by CaCl$_2$ treatment and water vapor permeability was decreased by 17${\sim}$22%. A solid form of alginates were irradiated with Co$^{60}$ gamma rays in the dose range of 2 to 10 kGy to make a low molecular weight alginate film, and then the intrinsic viscosity and the molecular weight of alginates were measured. Increasing the dose range of 2 to 10 kGy produced lower intrinsic viscosity and lower molecular weight, causing the decrease in the ES and WS. However, ER increased four times compared to that of without gamma ray dose, which is an indication of the different properties of algiante film. WVP of the films did not show any significant change at different doses.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.20 no.3
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• pp.77-84
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• 2014

Biodegradable nanocomposites were fabricated with poly (lactic acid) (PLA) and Nanomer$^{(R)}$ I.44P using ultrasonication (US). Processing conditions were optimized to obtain the maximum tensile properties of the nanocomposites. Poly (ethylene glycol) (PEG) was used as a plasticizer to avoid the brittleness of nanocompsoties. In order to disperse nanoclay into the PLA matrix, PEG and Nanomer$^{(R)}$ I.44P were firstly mixed and dispersed in the chloroform and followed by ultrasonication for 1 min With 10% PEG 400, tensile stress and Young's modulus of the nanocomposites decreased from 53.5 MPa and 2225 MPa to 37.0 MPa and 1757 MPa, respectively, while the elongation was increased from 4% to 21%. Tensile stress, Young's modulus, and elongation of nanocomposites were also increased with nanoclay concentration up to 2% (w/w) and were decreased with further increase in the nanoclay concentration. Transmittance of nanocomposites were significantly decreased from 62.5% for pure PLA film to 7.8% for 5% nanoclay containing nanocomposites. Water vapor permeability of the nanocomposites was also significantly decreased with nanoclay concentration and the minimum WVP of $3.5{\times}10^{-11}g{\cdot}m/m^2{\cdot}s{\cdot}Pa$ was obtained with 5% (w/w) nanoclay concentration. The PLA/Nanomer$^{(R)}$ I.44P nanocomposites showed a great potential as a environmental friendly food packaging material.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.69-74
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• 2004

'Mixing' and 'immersion' $CaCl_{2}$ treatment methods were tested for preparation of bio-degradable films using powders of sea mustard (Undaria pinnatifida) (leaf, stem, and sphorophyll), sweet tanlge (Laminaria japonica), and fusiforme (Hizikia fusiforme) by extracting alginate through acid-alkali extraction method. Except fusiforme powder, flexible, free-standing films were produced by both methods using all marine algae powders tested. Except water solubility (WS), surface color, tensile strength (TS), elongation at break (E), and water vapor permeability (WVP) did not show distinct difference between $CaCl_{2}$, treatment methods. Although TS, WVP, and WS of marine algae powder films were lower than those of alginate films, they indicate potential in application as a new source of bio-degradable packaging materials.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1184-1190
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• 1997

Corn zein coated carrageenan films were manufactured by immersing preformed ${\kappa}-carrageenan$ films into solution of different concentrations of corn zein (CZ) solids (10, 20, and 30% in 95% ethyl alcohol) with polyethylene glycol (20% w/w of CZ), glycerol (24% w/w of CZ). For all types of films, water vapor permeability (WVP), water solubility (WS), swelling ratio (SR), tensile strength (TS), percent elongation at break (E), heat sealing strength (HS), and Hunter color values (L, a, and b) were determined. WVP of corn zein coated ${\kappa}-carrageenan$ films decreased significantly (p<0.05) as the concentration of com zein increase. Coating with corn zein also decreased film WS and SR linearly with the concentration of corn zein. TS of corn zein coated carrageenan films decreased linearly with corn zein concentration. All the com rein coated carrageenan films showed heat sealing properties even though their sealing strength was less than half of corn zein film. Obviously corn zein coating affected color of ${\kappa}-carrageenan$ films, which was mainly caused by increase in yellowness (Hunter b-value).

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.12 no.2
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• pp.117-123
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• 2006

To mass-product useful biopolymer films, chitosan/gelatin blend films were prepared by solution casting method. Effect of mixing ratio, tensile strength(TS), elongation(${\Delta}E$) at break, total color difference(E), water vapor permeability(WVP) and oxygen permeability(OP) on chitosan/gelatin blend films properties were investigated. TS, ${\Delta}E$, E, WVP and OP values of chitosan/gelatin blend films were 43.43-38.30 MPa, 9.02-15.09%, 1.28-3.81, $0.8420-0.9673ng{\cdot}m/m^2{\cdot}s{\cdot}Pa$ and $1.5472{\times}10^{-7}-1.5424{\times}10^{-7}mL{\cdot}{\mu}m/m^2{\cdot}s{\cdot}Pa$, respectively. TS of the blend films decreased, while E and E of the blend films increased with increasing chitosan content. WVP and OP of the blend films did not show any significant relationship with mixing ratio and thickness of the blend films. OP of the blend films were lower than those of low density polyethylene and oriented polypropylene.

• Korean Journal of Food Science and Technology
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• v.37 no.1
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• pp.30-37
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• 2005

To mass-produce useful biopolymer films, chitosan/gelatin blend films were prepared by solution casting method. Effects of mixing ratio, tensile strength (TS), elongation (E) at break, total color difference (${\Dalta}E$), opacity, water vapor permeability (WVP), oxygen permeability (OP), and thermal properties on chitosan/gelatin blend films properties were investigated. TS, E, ${\Dalta}E$, opacity, WVP, and OP values were 58.24-22.01 MPa, 13.11-24.67%, 1.86-17.45, 0.3104-1.2161 nmO.D./${\mu}m$, $1.6875-1.7225ng{\cdot}m/m^{2}{\cdot}s{\cdot}Pa$, and $2.2380{\times}10^{-7}-2.2975{\times}10^{-7}\;mL{\cdot}{\mu}m/m^{2}{\cdot}s{\cdot}Pa$, respectively. TS of blend films decreased, while E, ${\Dalta}E$, and opacity increased with increasing chitosan content. WVP of blend films did not show any significant relationship with mixing ratio and thickness of blend films. Miscibility of films was examined over entire composition range by thermogravimetric analyzer (TGA) and dynamic mechanical analyzer (DMA). TGA results showed gelatin is more thermally stable than chitosan and some interactions among functional groups of two biopolymers. Glass transition temperature $(T_{2})$ of films as determined by DMA decreased with increasing content of chitosan in the blend. Results of thermal analysis indicate high miscibility among polymer components in the blend.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.372-378
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• 1998

Two types of formaldehyde-treated soy protein isolate (SPI) films, formaldehyde-incorporated and formaldehyde-adsorbed films, and control SPI films were prepared. Cross-linking effect of formaldehyde on selected film properties such as color, tensile strength (TS), elongation at break (E), water vapor permeability (WVP), and water solubility (WS) were determined. Physical properties of formaldehyde-incorporated films were not geneally different from those of control films, while almost all of those among formaldehyde-adsorbed films were significantly different. Through cross-linking development within formaldehyde-adsorbed films, WS decreased significantly (P<0.05) from 26.1% to 16.6%, and TS increased two times while E decreased two times compared with control films. This was caused by insolubilization and hardening of protein by cross-linking most likely attributed to the significant changes in properties of protein films reacted with formaldehyde.

• Applied Biological Chemistry
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• v.46 no.2
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• pp.113-116
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• 2003

Color value, total color difference $({\triangle}E)$, puncture strength (PS), tensile strength (TS), percent elongation(%E) at break values, and water vapor permeability (WVP) were determined for water-soluble chitosan films added with soy protein isolate (SPI) and $CaCl_2$. Mechanical and water vapor barrier properties of the chitosan films were affected by SPI and $CaCl_2$ concentrations. PS value $(174.5-448.8\;g_f)$ of the chitosan films increased with increasing concentration of $CaCl_2$ TS value of 0.05% $CaCl_2$-added chitosan films significantly increased to 1.58 MPa compared to 0.06 MPa of the control. %E values ranged from 12.25 to 44.80% and increased with increasing concentration of $CaCl_2$. WVP of $CaCl_2$-added films was lower than that of SPI-added films.