• Food Science and Biotechnology
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• v.15 no.6
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• pp.925-930
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• 2006

Chitosan-based nanocomposite films were prepared using a solution intercalation method incorporating varying amounts of organically modified montmorillonite (Cloisite 30B) from 0 to 30 wt%. The nanocomposite films prepared were optically clear despite a slight decrease in the transmittance due to the spatial distribution of nanoclay. X-ray diffraction patterns indicated that a certain degree of intercalation or exfoliation formed when the amount of clay in the film was low and that microscale tactoids formed when the clay content in the sample was high (more than 10 wt%). The tensile strength (TS) of the chitosan film increased when the clay was incorporated up to 10 wt% and then decreased with further increases in the clay content of the film. The elongation at break (E) increased slightly upon the addition of low levels of clay up to 5 wt% and then decreased with further increases in the amount of the clay in the film. The water vapor permeability (WVP) decreased exponentially with increasing clay content. The water solubility (WS) and swelling ratio (SR) of the nanocomposite films decreased slightly, indicating that the water resistance of the chitosan film increased due to the incorporation of the nanoclay.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.9
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• pp.1274-1280
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• 2012

Defatted grape seed meal protein (DGP) was extracted, and DGP films containing various plasticizers were prepared. To improve the mechanical properties of DGP film, nanoclay or gelatin was incorporated in the film-forming solution to manufacture DGP composite films. Among the plasticizers of fructose (FRU), sucrose (SUC), and polypropylene glycol (PPG), DGP film containing a SUC : PPG ratio of 2.5:0.5 exhibited the best film-forming ability. Addition of Cloisite $Na^+$ improved the mechanical properties of DGP film. Tensile strength (TS) and elongation at break (E) of the film containing 5% Cloisite $Na^+$ were 1.45 MPa and 71.97%, respectively. Regarding the DGP/gelatin composite films, TS and water vapor permeability (WVP) increased with increasing gelatin amount, whereas E decreased. In particular, the DGP/gelatin (2:2) composite film exhibited 20.95 MPa TS and 12.25% E. These results suggest that the DGP film prepared from defatted grape seed meal can be used as a food packaging material.

• Journal of Adhesion and Interface
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• v.8 no.4
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• pp.1-7
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• 2007

Waterborne polyurethane (WPU) which is environment friendly has been rapidly used in coating and adhesive industries. However, the WPU is deficient in chemical resistance, thermal resistance, and mechanical property compared to solvent-based polyurethane. In this study, the WPU was synthesized from two types of polyester polyols, 4,4-dicyclohexylmethane diisocyanate ($H_{12}MDI$), dimethylolpropionic acid (DMPA), triethylamine (TEA) and ethylenediamine (EDA), organophilic nanoclay. The thermal stability, mechanical property of the WPU nanocomposite dispersion increased with increasing clay concentration. Especially, their peel strength showed their maximum value at 3 wt% of organophilic nanoclay contents.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.2
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• pp.126-130
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• 2015

In this study, some materials are organized and experimented with variables to obtain the optimum mix proportion for the mechanical property of halogen free flame resistance compound with varying addition of nano clay. Tensile strength, density and stiffness are tested in the room temperature. In this study, unlike existing layered structure, nano clay with tabular structure is used and sufficient stiffness, strength, thermal stability and gas block capability can be achieved with small amount of addition. Tensile strength and elongation test show high rupture strength only in specimens with compatibilizing agents while density test shows average measurement in all the specimens except T-9. It was confirmed that the measurement value according to the additives in compatibilizing agent or in nano clay of hardness test represents similarly.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.120-126
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• 2016

Eco-friendly acrylic resin/clay nanocomposites containing pristine montmorillonite (PM) or modified clays (30B and 25A) were prepared from acrylic and styrenic monomers using non-aqueous dispersion (NAD) polymerization. Effect of nanoclays on physical properties of polymerization product and resulting nanocomposites was investigated. In view of NAD particle stability, addition of nanoclay at the beginning of polymerization is proved to be good. Results of gel fraction, acid value and viscosity of the NAD product showed that nanocomposites containing clay 25A showed better physical properties than the ones with other clays. GPC results exhibit the increase in molecular weight and decrease in polydispersity index for the 25A nanocomposite. Increase in layer distance confirmed from XRD analysis showed good dispersion of 25A in the nanocomposite. Thermal and dynamic mechanical analysis showed that highest glass transition temperature and storage modulus for 25A nanocomposites. These results indicate that 25A nanoclay gives the best properties in the process of non-aqueous dispersion polymerization of acrylic resin/nanoclay nanocomposites.

• Elastomers and Composites
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• v.46 no.1
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• pp.37-44
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• 2011

Effect of organo nanoclay (Cloisite 30B) on the polyesterification of adipic acid (AA) with diethylene glycol(DEG) was investigated with p-toluene sulfonic acid (p-TSA) (Br${\phi}$nsted acid) and butylchlorotin dihydroxide (Lewis acid) catalyst at 383 and 423 K. The initial [OH]/[COOH] molar ratio was two and the concentration of the catalysts in the reactants was 0.14 mol% based on the total reactants. The kinetics of the polyesterification was interpreted with the conversion data that was calculated from the acid values of the reactant-product mixture. The reaction rate of the polyesterification, which was catalyzed with p-TSA, exhibited the second-order dependency on AA concentration. When Butylchlorotin dihydroxide was used, the reaction rate revealed the first-order dependency on AA concentration. The activation energy of the reactions catalyzed with p-TSA and Butylchlorotin dihydroxide were calculated at 42.2 and 63.8 kJ/mol, respectively. Addition of 5 wt% Cloisite 30B to the reactant significantly diminished the activity of p-TSA, so the reaction rate decreased and the activation energy was calculated at 72.9 kJ/mol. Butylchlorotin dihydroxide catalyst maintained its activity regardless of the addition of Cloisite 30B to the reactant and the activation energy was calculated to 61.8 kJ/mol. Lewis acid catalyst, butylchlorotin dihydroxide, was more effective than Br${\phi}$nsted acid catalyst for the esterification of AA with DEG.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.3
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• pp.157-163
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• 2022

The demands for Home Meal Replacement (HMR) products are continuously increasing owing to the convenience of instant food and online food delivery. Ready-to-heat (RTH) products have received massive attention in the HMR industry because these products can be easily warmed using a microwave oven. However, the conventional microwave packaging should be opened before microwave heating to prevent bursting or food loss owing to the steam-pressure build-up inside the package. Open packaging might lead to non-uniform food heating and cross-contamination. Therefore, packaging materials that are able to release steam without opening are of interest to the HMR industry. In this study, polylactic acid(PLA)/polyethylene glycol(PEG)/nanoclay composite films were manufactured using an extrusion method as packaging materials with a smart steam-releasing function. The introduction of PEG to the PLA imparted a steam self-releasing feature to the composite films owing to the morphology change of composite films during microwave heating. Further, PEG increased the ductility of PLA, which in turn prevented bursting caused due to the steam-pressure build-up. The uniform dispersion of nanoclay obtained by a twin-screw extrusion led to stronger mechanical properties. Therefore, the smart composite films developed here can be applied as microwave packaging materials with a self-releasing function.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2009.10a
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• pp.377-385
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• 2009

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.1
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• pp.51-56
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• 2015

The object of this study is to obtain the optimum mix proportion of halogen free compound with flame resistance and, for the purpose, thermal/electrical characteristics test are conducted using compatibilizing agents, flame resistance agents, hydroxide aluminum, sunscreen, antioxidant and silicon oil on the base resin of linear low density polyethylene (LLDPE), Ethylene vinyl acetate copolymer (EVA). Existing compound method accompanies many requirements to be satisfied including a lot of addition of flame resistance agents, prohibition of impact on mixing capability with base and property and etc. In this study, different from the existing method, the optimum mix proportion is determined and experimented by adding nano clay. Oxygen index test shows no difference between specimens while T-6, T-9 shows oxygen index of 29[%] and 26[%], respectively. This is concluded that hydroxide aluminum, which is a flame resistance agent, leads low oxygen index. From UL94-V vertical flame resistance test, the combustion behavior is determined as V-0, Fail based on UL94-V decision criteria. Viscometry shows low measurements in specimens with separate addition of compatibilizing agents or nano clay. Volume resistivity test shows low measurement mainly in specimens without compatibilizing agents. Therefore, with the flame resistance compound shows better performance for thermal/electrical property and the optimum mix proportion are achieved among many existing materials.

• Food Science and Industry
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• v.50 no.2
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• pp.52-59
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• 2017

Nano-packaging is defined as food packages produced with nanoparticles or using nanotechnology in their process. Nano-packaging has become more available in the current market because of its enhanced functional properties such as antimicrobial and barrier properties. However, consumers have worried about toxicity by migration of nanomaterials from packaging to food. Currently, many commercialized products are coated or composited with inorganic nanomaterials such as nanosilver, nanoclay, zinc oxide, titanium dioxide, and so on. In this study, nanomaterials used in food packaging were classified and the commercially available nano-packaging were screened. Study on the migration of nanomaterials in various food simulants was also summarized.