Preparation of chitosan/polyvinyl alcohol blended films containing sulfosuccinic acid as the crosslinking agent using UV curing process

Yun, Yeon-Hum,Lee, Chang-Moon,Kim, Youn-Sop,Yoon, Soon-Do Elsevier 2017 Food Research International Vol.100 No.1

<P>This paper reports on a method of preparing chitosan-based films to which sulfosuccinic acid (SSA) is added for crosslinking agent with/without UV curing treatment and applications of a coating materials for foods. The physical, thermal, and optical properties of the UV cured chitosan-based films are investigated including their tensile strength (TS), elongation at break (%E), degree of swelling (DS), solubility (S), and water vapor absorption as well as their biodegradability in soil and applicability of the coating on a fruit. We also evaluated the physical properties of the prepared films to which glycerol (GL), xylitol (XL), and sorbitol (SO) are added to be used as plasticizers. The surface and topography of the prepared films are investigated by scanning electronic microscopy (SEM) and atomic force microscopy analysis (AFM). The results indicate that the films UV cured for 20 min possess optimal physical and thermal properties compared to that of non-cured films. The mechanical, thermal, and water barrier properties of SO-added film are also found to be superior to other films with added GL and XL. The degree of biodegradability revealed that the films are degraded by about 40-65% after 220 days.</P>

Preparation of functional chitosan-based nanocomposite films containing ZnS nanoparticles

Yun, Yeon-Hum,Youn, Hyun-Gi,Shin, Jin-Young,Yoon, Soon-Do Elsevier 2017 INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES Vol.104 No.1

<P><B>Abstract</B></P> <P>In this study, nanocomposite films were synthesized by chitosan (CH), PVA, ZnS, sulfosuccinic acid, and plasticizers. The nanocomposite films were cross-linked by the heat curing process. ZnS was synthesized by the reaction of Zn(CH<SUB>3</SUB>COO)<SUB>2</SUB> and Na<SUB>2</SUB>S2O<SUB>3</SUB>·5H<SUB>2</SUB>O in aqueous solution via a template-free hydrothermal process. The prepared ZnS and CH/PVA nanocomposite films were characterized by X-ray diffraction, Fourier transform IR spectroscopy, and scanning electronic microscopy. The results of this study confirmed the presence of specific peaks of ZnS in the prepared nanocomposite films, and the intensity of these peaks increased with increasing ZnS contents. Tensile strength, elongation at break, water barrier properties, and thermal properties of the prepared nanocomposite films were also investigated, indicating that the addition of ZnS nanoparticles improved the physical and thermal properties. In addition, the photocatalytic degradability of the prepared films containing ZnS nanoparticles was evaluated using 2,4-dichlorophenoxyacetic acid and methyl orange.</P>

Physical properties of mungbean starch/PVA bionanocomposites added nano-ZnS particles and its photocatalytic activity

Yun, Yeon-Hum,Kim, Eun-Sik,Shim, Wang-Geun,Yoon, Soon-Do THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2018 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.68 No.-

<P><B>Abstract</B></P> <P>The main objective of this study is to prepare the bionanocomposite films using mungbean starch (MBS), PVA, ZnS, and plasticizers, and to evaluate the physical properties, thermal stability, and photocatalytic activity. The bionanocomposite films were cross-linked by heat-curing process. The ZnS and bionanocomposite films were characterized by FT-IR, XRD, and SEM. The results indicated that the mechanical properties and water resistance enhanced up to 1.2–1.5 times by the addition of nano-ZnS particles, and the thermal stability was improved by the addition of nano-ZnS particles. The photocatalytic activity of the bionanocomposite films added nano-ZnS particles was examined using bisphenol A (BPA) and methyl orange (MO). In addition, the photodegradation efficiency of BPA and MO was evaluated using the pseudo-first order kinetic model (PFOK).</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

The characterization of glass-ceramics made from waste glass and fly ash

Yeon-Hum Yun,Cheon-Young Park,Soon-Do Yoon 한양대학교 세라믹연구소 2007 Journal of Ceramic Processing Research Vol.8 No.6

Glass-ceramics with well-crystallized whisker-type crystals were prepared by milling and heat treatment using fly ash from a thermal power plant and waste glass cullet. Various heat treatment temperatures [850, 900, 950 and 1000 oC] were used to obtain a glass-ceramics that have the optimum crystal phase and mechanical properties. The crystallization of a whisker-type phase in the matrix was achieved in the heat treatment temperature range of 950-1000 oC, and the whisker-type main crystal phase in the glass-ceramics was wollastonite [CaSiO3] The heat treatment temperature range [950-1000 oC] also brought about much better mechanical properties. Crystallinity, morphological properties, and chemical compositions were observed by Xray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), and an energy dispersive X-ray spectrometer (EDS). Various properties such as density, compressive strength, bending strength and chemical durability were also examined. Glass-ceramics with well-crystallized whisker-type crystals were prepared by milling and heat treatment using fly ash from a thermal power plant and waste glass cullet. Various heat treatment temperatures [850, 900, 950 and 1000 oC] were used to obtain a glass-ceramics that have the optimum crystal phase and mechanical properties. The crystallization of a whisker-type phase in the matrix was achieved in the heat treatment temperature range of 950-1000 oC, and the whisker-type main crystal phase in the glass-ceramics was wollastonite [CaSiO3] The heat treatment temperature range [950-1000 oC] also brought about much better mechanical properties. Crystallinity, morphological properties, and chemical compositions were observed by Xray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), and an energy dispersive X-ray spectrometer (EDS). Various properties such as density, compressive strength, bending strength and chemical durability were also examined.

Starch와 PVA를 이용한 생분해성 필름의 제조와 물리적 특성

윤연흠 ( Yeon Hum Yun ),윤순도 ( Soon Do Yoon ) 조선대학교 공학기술연구원 2008 공학기술논문지 Vol.1 No.1

We report on the preparation and physical properties of films using corn starch and poly(vinyl alcohol) (PVA). Starch/PVA biodegradable films were synthesized with a mixing process and casting method. Glycerol (GL), sorbitol (SO), malic acid (MA), tartaric acid (TA) and citric acid (CA) were used as additives. Gelatin (GE) was used as filler for increasing of physical properties of starch/PVA biodegradable films. The additives and the influence of filler in films on the physical properties of the films were investigated. The mechanical properties, tensile strength (TS), elongation al break (% E), degree of swelling (DS), and solubility (S) of starch/PVA blend film were examined adding GL, SO, MA, TA and CA as additives and GE as filler. The results of the measurements indicated that the GE-added films were better than the other films.

토레몰리노스 협약 발표에 따른 기대효과 및 우리나라 대응방안

이윤철(Yun-Cheol Lee),연효흠(Yyo-Hum Yeon),윤귀호(Gwi-Ho Yun) 한국해사법학회 2008 해사법연구 Vol.20 No.2

  그 동안 IMO를 위시한 어선 및 어선원관련 각종 국제기구에서는 어업부문의 안전 및 어선원의 안전성 향상의 문제를 해결하기 위하여 각종 규정들을 제ㆍ개정하여 왔다. 소형어선의 해양사고 증가로 소형어선 및 어선원을 위한 안전에 대해서도 관심이 고조되면서 그 규정의 적용범위도 점차 소형어선으로 확대되고 있다. 특히 IMO 및 ILO에서 제정된 강제 협약인 1993년 토레몰리노스협약 의정서와 2007년 통합어선원노동협약의 경우 공법적인 성질을 지니고 있어서, 관련 협약을 준수하지 아니하고는 어선의 국제적 운항이 현실적으로 불가능하다. 따라서 우리 나라는 이들 협약의 발효를 위한 긍정적 검토를 위하여 어선안전에 관한 국제적 흐름을 주도하는 IMO, FAO 및 ILO 등 관련 국제기구의 동향을 구체적으로 파악하고 이 분야의 연구를 지속적으로 수행해야 한다. 또한 우리나라와 어업현실이 비슷한 동아시아 수산강국인 한ㆍ중일의 협력을 통한 국제적인 공동대응이 필요하다. 이렇게 하여 우리 나라는 우리나라는 어선관련 협약에 대한 능동적인 관점의 변화로 창의적이고 현실적인 대안을 선점 공포함으로써 어선안전 분야에서도 선도국가로 거듭나야 할 것이다.   In this paper, it is argued that safety at sea should be reinforced with the adoption of 1993 Torremolinos Protocol(I993 Protocol) by IMO(International Maritime Organization) with regulations amendment.<BR>  Many international laws and regulations on international fishing vessels safety including 1993 Protocol and Work in fishing convention 2007(ILO Convention No.188) by ILO(International Labour Organization) have significant impact on national fishing industry because they are of mandatory nature that it is almost impossible for the fishing vessels to navigate & operate without complying with such regulations, furthermore scope of such regulations may expand even into small fishing vessels. Accordingly, considering such impact, most advanced countries in maritime and fishing industry actively engage in from the legislative stage of such regulations and carefully review before rectification or reservation even after entering into any related conventions.<BR>  However, the 1993 Protocol has serious defect to be applied internationally because at the time of drafting, only European standards for fishing vessel types and working area conditions were taken into consideration. Also 1974 SOLAS(International convention for the safety of life at sea by IMO) which was the parent of the 1993 Protocol that does not rightfully represent present maritime environments was established 14 years ago. IMO strongly demands its member countries to rectify the 1993 Protocol but perceiving such problem, it also promotes new enactment or amendment of the 1993 Protocol and enactment of ILO Convention No.188 is expected to accelerate such process.<BR>  In order for ROK to actively participate in such international trend, it is recommended that ROK, above all, advocates amendment of the Protocol. Detailed action plans can be as follows ; Firstly, ROK should closely observe the trend of international institutes in relation to maritime and fishery industry and continuously study on such movement. Secondly, International forums consisting of experts on fishing vessel safety from ROK, China and Japan should be organized in order to give organized response to any changes or movement of such institutions. Lastly, in long-term view, it should step forward to organize Pan-Asian forums for the fishing vessel safety to further systematically cope with the European countries logic.

Photocatalytic properties of ceramics TiO2 nanocomposites from waste resources

Soon-Do Yoon,이정환,Yeon-Hum Yun 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.2

Ceramics TiO2 nanocomposites were prepared by using titanium oxide (TiO2) nanoparticles, fly ash from the thermal powerplant and the mixed waste glass powder. We applied a mechanical milling method and thermal reaction in this process. Thephotocatalytic activities were estimated for methyl orange (MO), acetaldehyde (ATA), 2,4-dichlorophenoxyacetic acid (2,4-D),and methylene blue (MB) as photodegradation targets. Crystallinity, morphological properties, and chemical compositions forprepared ceramics TiO2 nanocomposites were also observed by X-ray diffraction (XRD), field emission-scanning electronmicroscopy (FE-SEM), and energy dispersive X-ray spectrometer (EDS). In addition, density, compressive strength, bendingstrength and chemical durability were measured to characterize the physicochemical properties of TiO2 nanoparticle contents (0-20 wt%). It was verified that addition of TiO2 nanoparticles considerably improves the physicochemical properties of theprepared nanocomposites samples. With increased TiO2 nanoparticle content, the photocatalytic activities of the ceramics TiO2nanocomposites for photodegradation target materials increased under UV light irradiation. The degree of photocatalyticdegradation of MO, ATA, 2,4-D, and MB in the ceramics TiO2 nanocomposites improved to about 0.264, 0.141, 0.302, and 0.368,respectively, after the UV irradiation for 240 min when 20 wt% TiO2 nanoparticle was added. In addition, the photocatalyticdegradation rate of photodegradation target materials was evaluated using the pseudo-first-order kinetics proposed by Lagergren.

Recycling of glass waste and shells by the fabrication of glass-ceramics reinforced by a whisker-type wollastonite phase

황규석,김병훈,안준형,강보안,Yeon-Hum Yun,Young-Sun Jeon 한양대학교 세라믹연구소 2004 Journal of Ceramic Processing Research Vol.5 No.2

Glass-ceramics showing a high mechanical strength reinforced by whisker-type wollastonite crystals were prepared by a milling and heat-treatment process using various glass waste and shells as starting materials. In order to blend the starting materials and to accelerate the interaction between the glass and shell during annealing, mechanical milling using a disk-type mill was employed. Formation of whisker-type β-wollastonite crystals was observed in the glass matrix using a X-ray diffraction analysis and a field emission-scanning electron microscope. On increasing the annealing temperature from 800oC and 900oC to 1000oC, the compressive strength of the specimens increased.

Calcium Phosphate Forming Ability of Thermally Oxidized Titanium Implant

Hwang, Kyu-Seog,Yun, Yeon-Hum,Min, Seon-Suk,Lee, Yong-Ryeol,Park, Yeong-Joon 대한금속학회 2002 METALS AND MATERIALS International Vol.8 No.4

Commercially pure titanium disks as-received and heat treated at 600℃ in air for 10 min were used to investigate differences in calcium phosphate forming ability. Crystallinity and surface morphology were analyzed by Xray diffraction and field emission scanning electron microscopy. Energy dispersive X-ray spectrometry and Fourier transform infrared reflection spectroscopy were used to collect information on chemical composition and chemical surface structure. TiO_2 layers with a heterogeneous structure produced by heat treatment showed high in vitro calcium phosphate forming ability in contact with Eagle's minimum essential medium.

Chemical durability of glass-ceramics obtained from waste glass and fly ash

Soon-Do Yoon,Yeon-Hum Yun 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.2

Applying the mechanical milling method and annealing procedure, we prepared glass-ceramics using fly ash from a thermal power plant mixed with waste glass cullet to resolve the environmental waste recycling problem and find out the optimum crystallizing mechanism. The chemical durability of the heat-treated specimens [850oC, 950oC and 1000oC] was investigated by measuring the weight changes, morphological properties, and chemical composition at the sample surfaces before and after acid immersion by field emission–scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectrometry (EDS). Various properties, such as density, compressive strength, bending strength and Vickers hardness of specimens [before and after acid immersion] were observed. Regardless of chemical treatment, glass-ceramics heat-treated at 850oC, 950oC and 1000oC showed sufficient mechanical properties for practical usage. Applying the mechanical milling method and annealing procedure, we prepared glass-ceramics using fly ash from a thermal power plant mixed with waste glass cullet to resolve the environmental waste recycling problem and find out the optimum crystallizing mechanism. The chemical durability of the heat-treated specimens [850oC, 950oC and 1000oC] was investigated by measuring the weight changes, morphological properties, and chemical composition at the sample surfaces before and after acid immersion by field emission–scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectrometry (EDS). Various properties, such as density, compressive strength, bending strength and Vickers hardness of specimens [before and after acid immersion] were observed. Regardless of chemical treatment, glass-ceramics heat-treated at 850oC, 950oC and 1000oC showed sufficient mechanical properties for practical usage.