• 한국응용과학기술학회지
• /
• 제26권3호
• /
• pp.288-296
• /
• 2009

In this study, the silica-based hybrid material with high barrier property was prepared by incorporating ethylene-vinyl alcohol (EVOH) copolymer, which has been utilized as packaging materials due to its superior gas permeation resistance, during sol-gel process. In preparation of this EVOH/$SiO_2$ hybrid coating materials, the (3-glycidoxy-propyl)-trimethoxysilane (GPTMS) as a silane coupling agent was employed to promote interfacial adhesion between organic and inorganic phases. As confirmed from FT-IR analysis, the physical interaction between two phases was improved due to the increased hydrogen bonding, resulting in homogeneous microstructure with dispersion of nano-sized silica particles. However, depending on the range of content of added silane coupling agent (GPTMS), micro-phase separated microstructure in the hybrid could be observed due to insufficient interfacial attraction or possibility of polymerization reaction of epoxide ring in GPTMS. The oxygen barrier property of the mono-layer coated BOPP (biaxially oriented polypropylene) film was examined for the hybrids containing various GPTMS contents. Consequently, it is revealed that GPTMS should be used in an optimum level of content to produce the high barrier EVOH/$SiO_2$ hybrid material with an improved optical transparency and homogeneous phase morphology.

• 한국포장학회지
• /
• 제3권2호
• /
• pp.3-16
• /
• 1996

This study was investigated to the effect of oxygen barrier of four different packaging films of the shelf life of proessed meat product by the simulated distribution test and storage test. The microbial growth, pH, VBN content, TBA value, color change and sensory evaluation were compared during the 2-month storage period at 4, 10, $20^{\circ}C$ after finished the simulated distribution test. The oxygen transmission rates ($cc/m^2$ day) were BF001: 27,88; BF003; 12.30;NY; 77.98; EVOM; 0.41 respectively. The packaging films were not effected on the changes of pH, VBN content, TBA value and color during the storage period. The aerobic microbial growth was increased only at $20^{\circ}C$ in the order of growth rate in the following films;NY > BF001 > BF003 > EVOH. Therefore, the microbial growth was affected significantly by the properties of oxygen barrier off packaging films and it should be an indicator of establishing the shelf life processed meat product.

• Journal of Applied Biological Chemistry
• /
• 제54권3호
• /
• pp.190-196
• /
• 2011

Effectiveness of edible coatings containing soy protein isolate (SPI), in reducing oxidative browning and moisture loss during storage ($4^{\circ}C$) of cut apples, potatoes, carrots, and onions was investigated. The SPI coatings were shown to have antioxidative activity. Furthermore, addition of carboxymethyl cellulose (CMC) to the formulations significantly improved its antioxidative activity. Oxidative discoloration, as determined by Commission Internationale De I'Eclairage (CIE) lightness ($L^*$), redness ($a^*$), and yellowness ($b^*$) color scale, was significantly reduced (p <0.05) by SPI coating treatments over a storage time of 120 min. Loss of lightness was reduced by SPI coatings with and without CMC. These respectively showed 4.03 and 3.71% change of $L^*$ value compared to 8.56% for control. Browning of the control in cut potatoes was significantly increased by 106.6% in contrast to 34.3 and 35.2% for SPI coatings with and without CMC, respectively. The $b^*$ values also reflected effectiveness of SPI. Moisture barrier effect was significantly better for the treatments, compared to the control. SPI coatings reduced moisture loss in apples and potatoes, respectively, by 21.3 and 29.6% over the control. Cut onions did not show any treatment effect both in terms of browning and moisture loss. SPI coatings prove to be good moisture barrier and antioxidative property.

• 한국포장학회지
• /
• 제24권1호
• /
• pp.13-16
• /
• 2018

Powdered infant formula is susceptible to oxidation in the presence of oxygen. Even though the product is usually packaged in nitrogen atmosphere, the oxygen ingress through the package layer may occur in case of flexible pouches and affects the oxidation of the product. $O_2$ barrier of the package is thus important variable to protect the product from oxidative deterioration. $O_2$ barrier property was investigated for aluminum-laminated small pillow packs of $3.5{\times}17.5cm$. Storage temperature and combination of primary and secondary packages were evaluated as variables affecting the barrier for conditions of empty pouch flushed with nitrogen. Apparent oxygen transmission rate of the primary package exposed to air was $2.32{\times}10^{-3}mL\;(STP)\;atm^{-1}\;d^{-1}$ at $30^{\circ}C$ and its temperature dependence could be explained by activation energy of $28.5kJ\;mol^{-1}$ in Arrhenius relationship. The additional secondary package of nylon/PE film containing 20 primary packages was ineffective in modulating package $O_2$ transmission and was only marginally helpful when combined with oxygen scavenger. The same was true in suppressing the product oxidation when the primary package was filled with 14 g of the formula.

• 전기학회논문지
• /
• 제63권1호
• /
• pp.80-84
• /
• 2014

The discharge characteristics of Surface Dielectric Barrier Discharge (SDBD) reactor are investigated to find optimal driving condition with adjusting various parameter. When the high voltage with sine wave form is applied to SDBD source, successive pulsed current waveforms are observed owing to multiple ignitions through the long discharge channel and wall charge accumulation on the dielectric surface. The discharge voltage, total charge between dielectrics, mean energy and power are calculated from measured current and voltage according to electrode gap and dielectric thickness. Discharge mode transition from filamentary to diffusive glow is observed for narrow gap and high applied voltage case. However, when the diffusive discharge is occurred with high applied voltage, the actual firing voltage is always lower than that with low driving voltage. The $Si_3N_4$, $MgF_2$, $Al_2O_3$ and $TiO_2$ are considered for dielectric protection and high secondary electron emission coefficient. SDBD with $MgF_2$ shows the lowest breakdown voltage. $MgF_2$ thin film is proposed as a protection layer for low voltage atmospheric dielectric barrier discharge devices.

• 전기학회논문지P
• /
• 제67권4호
• /
• pp.214-220
• /
• 2018

Light sources induced by gas discharge using rare gases have been widely used in the thin film deposition, the surface modification and the polymer etching. A dielectric barrier discharge (DBD) has been developed in order to consistently emit light and control the wavelength of the emission light. However, much research on the characteristics of the movement of discharge particles is required to improve the efficiency of the light lamp and the life-time of the light apparatus in detail. In this paper, we developed a He DBD discharge simulation tool and investigated the characteristics of discharge particles which were electrons, two positive ions ($He^+$, $He_2^+$) and 5 excited particles ($He^*(1S)$, $He^*(3S)$, $He^*$, $He^{**}$, $He^{***}$). The discharge currents showed the transition from pulse mode to continuous mode with the increase of power. With the accumulated charges on the barrier walls, the discharge current was rapidly increased and caused oscillation of the discharge voltage. As the gas pressure increased, $He_2^+$ and $He^*(3S)$ became the dominant activated particles. The input power was mostly consumed by electrons and $He_2^+$ ion. And the change curve showed that power consumption by electrons increased more with gas pressure than with source voltage or frequency.

• 한국진공학회지
• /
• 제6권2호
• /
• pp.143-150
• /
• 1997

본 연구에서는 1000$\AA$두께의 Molybdenum화합물(Mo, Mo-N,$MoSi_2$, Mo-Si-N)의 Cu에 대한 확산방지막으로서의 특성을 면저항측정장비(four-point-probe), XRD, XPS, SEM, RBS 분석을 통하여 조사하였다. 각 박막층은 dc magnetron sputtering장비를 이용하 여 증착되었고 $300^{\circ}C$-$800^{\circ}C$의 온도구간에서 30분동안 진공열처리하였다. Mo 및 $MoSi_2$ 방지 막은 낮은 온도에서 확산방지막으로서의 특성파괴를 보였다. 결정립계를 통한 Cu의 확산과 Mo-실리사이드내의 Si의 Cu와의 반응이 그 원인인 것으로 사료된다. 질소를 첨가한 시편의 경우 확산방지특성 파괴온도는 Mo-N방지막의 경우 $650^{\circ}C$-30분, Mo-Si-N방지막의 경우 $700^{\circ}C$-30분으로 향상되었다. Cu와 Si의 확산은 방지막의 결정립계를 통하여 더욱 빠르게 확 산된다. 따라서 증착시 결정립계를 질소와 같은 물질로 채워 Cu와 Si의 확산을 저지할 수 있을 것으로 사료된다. 본 실험결과에서의 질소첨가는 이와 같은 stuffing 효과외에도 Mo- 실리사이드 박막의 결정화 온도를 다소 높인 것으로 나타났고, 그 결과 결정립계의 밀도를 감소시켜 확산방지막으로서의 특성을 향상시킨 것으로 사료된다. 또한 질소첨가는 실리사이 드내의 금속과 실리콘과의 비를 변화시켜 확산방지막의 특성에 영향을 미친 것으로 보인다. 본 실험에서 조사된 확산방지막 중에서는 Mo-Si-N박막이 Cu와 Si간의 확산을 가장 효과적 으로 저지시킨 것으로 나타났으며 $650^{\circ}C$-30분까지 안정한 특성을 보였다.

• 멤브레인
• /
• 제33권6호
• /
• pp.447-453
• /
• 2023

컴퓨터 시스템의 성능 및 다양한 전산모사 프로그램의 발전으로 더 복잡한 원소로 이루어진 화학시스템의 해석이 가능해지고, 그에 따라 분자동역학 전사모사를 활용한 연구가 활발히 이루어지고 있다. 특히, 기존에는 실험위주로 진행되던 고분자 막에 대한 기체 투과 특성을 계산하는 연구가 관심을 받고 있고, 식품포장, 의약품등에 사용되고 있는 기체차단성 막에 대한 분자동역학 연구가 많이 이루어지고 있다. 최근 실크 피브로인을 이용해 코팅막을 만들었을 때 기체 차단 효과가 나타난다는 보고가 있었고, 본 연구에서는 이러한 실크 피브로인을 활용해 복합막을 만들었을 때 산소 차단 효과가 나타나는지 확인하고자 분자동역학 전산모사를 이용해 연구를 진행하였다. 단일 모델을 제작하고 기체 투과 특성을 계산하고 실험값과 비교를 통해 모델이 실제 실험 결과를 반영하는 것을 확인하였고, 실제 복합막 모델을 만들어 고분자 내에서 기체 이동경로 분석을 진행한 결과 산소 분자가 피브로인 영역을 통과하지 못하고 막히는 것을 보여주었다. 따라서, 실크 피브로인이 도입된 복합막이 산소 차단 성능이 우수하여, 식품포장 등에 유용할 것으로 기대된다.

• 한국화재소방학회논문지
• /
• 제24권2호
• /
• pp.21-30
• /
• 2010

본 연구는 화학보호복 원단들에 대하여 내화학성 및 난연성을 조사하기 위하여 ASTM 및 ISO의 방법을 이용하여 내화학성 및 화재위험성시험을 실시하였다. 시험결과 폴리에틸렌의 경우 전혀 난연성이 없는 것으로 분석되었지만 고무에 데카브롬 등 난연성 물질이 첨가된 불소고무 원단이 뛰어난 난연성을 보였다. 특히 현재 소방용 방열복으로도 사용되고 있는 알루미늄 필름에 아라미드원단을 라미네이팅한 원단이 가장 뛰어난 난연성을 보였다. 하지만 내화학성에 있어 알루미늄은 4% NaOH에 부식되는 결과를 보이고 있어 이를 극복하기 위한 방안으로는 다층의 베리어성 필름을 사용하는 것이 좋을 것으로 사료된다. 아울러 난연성 시험결과 알루미늄필름과 폴리머 베리어성 필름을 소재로 만든 Dual skin과 불소고무에 난연성 물질이 포함된 것을 소재로 만든 Single skin이 화학보호복으로 적합한 것으로 판단된다. 또한 열방호실험과 열전달지수실험결과 두께의 증가와 다층구조일수록 TPP와 HTI 증가하는 것으로 나타났다. 향후 화학 보호복 원단의 화재위험성 및 내화학성시험 등 지속적 연구와 보완이 적절한 화학보호복 원단 성능개선에 기여할 것으로 기대된다.

• 한국진공학회지
• /
• 제9권3호
• /
• pp.221-226
• /
• 2000

졸겔법 및 진공증착법으로 $WO_3$ 및 $V_2O_5$ 박막을 제조하고, 리튬이온을 이용하여 전기변색 소자를 제작한 후 광학적 특성을 조사하였다. 측정결과 졸겔법으로 제조된 $WO_3$ 박막과 $V_2O_5$ 박막을 수증기 분위기에서 $500^{\circ}C$로 1시간 열처리한 경우 가장 우수한 투과율 변화량을 나타내었다. 정.역방향 동작을 거듭할수록 $WO_3$막의 텅스텐과 ITO막의 인듐이 상호 확산하는 것을 관찰할 수 있었으며 이를 방지하기 위해 수백 $\AA$의 텅스텐 박막을 ITO와 $WO_3$막 사이에 삽입한 결과, cyclic voltamogram의 peak의 감소량이 1/10 이하로 감소하였으며, 리튬이온의 흐름에 의한 인듐과 텅스텐의 이동을 효과적으로 방지할 수 있었다.