• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.2
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• pp.71-77
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• 2023

Absorbable periodontal tissue regeneration barrier membranes (total 6; domestic 4; import 2) were comparatively analyzed. In the case of the xenograft barrier membrane, the collagen product had excellent tensile strength but low strain, and the porcine pericardial membrane had good mechanical properties, but its thickness was too thick to control. The synthetic PLLA membrane manufactured by the electrospinning had a relatively low water absorption capacity. However, the hybrid barrier membrane was able to control mechanical properties and biocompatibility through proper mixing of synthetic polymer and natural polymer. DA02 (PLLA/gelatin), a newly developed hybrid absorbable periodontal tissue regeneration membrane that is entirely dependent on imports, can be applied to an absorbable periodontal tissue regeneration barrier membrane due to suitable mechanical properties and biocompatibility.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.99-99
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• 2011

최근 건강에 대한 관심이 높아지면서 천연 기능물질을 이용한 고기능 및 고부가가치 상품개발이 여러 산업분야에서 일반화되는 추세이다. 대표적으로 마이크로캡슐은 원하는 기능을 발휘할 수 있는 기능성 물질을 다양한 방법으로 다양한 제품에 부여함으로써, 기능성 물질을 오랜 기간 동안 외부로 방출하거나 외부의 환경으로부터 보호하는 수단으로 각광받고 있다. 이러한 마이크로캡슐은 의약분야 제초제, 멸충제, 곰팡이 방지제, 살균제로 적용되는 농약분야, 식품 분야, 화장품 분야 등의 전반에 걸쳐 응용 및 연구가 활발히 이루어지고 있다. 이에 본 연구에서는 다양한 나노 합성기술과 유/무기 하이브리드를 이용해 서방화 관련 기술을 개발하여 보습성, 항균, 노화방지, 외부 유해물질로부터의 피부보호 특성을 가진 인체 친화형 복합기능성 섬유 가공조제를 개발하여 다양한 섬유소재에 적용하고자 하며, 궁극적으로 기존 선진국 제품의 기능을 뛰어넘는 원천기술, 즉 새로운 가공제 합성과 응용성, 그 성능평가와 동시에 최적의 처리기술을 개발함으로써 섬유제품의 부가가치를 높이는 계기를 마련하고자 한다. 본 연구에서는 나노미터 직경을 갖는 침상형의 주형(hydroxyapatite)을 이용하여 중공 나노구조체를 제조 한 후 이에 천연고분자를 혼합하여 초음파처리 후 유/무기 하이브리드 기술을 이용한 서방성 가공제를 합성하였다. 중공의 나노구조체 확인은 투과전자현미경(TEM)을 이용하였으며, 주형의 나노구조체는 주사전자현미경(FE-SEM)으로 확인하였다. 이상의 결과를 통해 본 연구에서 제안한 방법이 나노구조체의 새로운 합성방법으로써 가능성을 확인할 수 있었다.

• Korean Journal of Microbiology
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• v.28 no.3
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• pp.229-235
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• 1990

A rapid and sensitive method to detect the extracellular enzymatic activity of bacteria colonies grown on agar plates is described. Selective agar media supplemented with protein, starch, chitin, Tween-80, etc. are conventionally used to detect biochemical properties of bacteria. It has been experimentally demonstrated with bacteria pure cultures that fluorogenic Methylumbelliferyl (MUF)-substrates are excellent substrate analogues for normally occurring polymers. Based on MUF-substrate hydrolysis the new method provides reliable qualitative estimates of extracellular enzymatic properties of bacteria within minutes using pure cultures as well as agar p;ates prepared for colony counts. Extracellular enzyme activities of heterotrophic bacteria from freshwater ecosystems and marine sediment using this method are discussed.

• Membrane Journal
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• v.29 no.4
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• pp.231-236
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• 2019

In this study, alginate-based hydrogel membranes composed of hydrogel beads and highly tough hydrogel matrix including moisturizing oil and natural emulsifier were prepared and their elution characteristics were evaluated. As a result, it was confirmed that the elution rate of the moisturizing oil component can be controlled within a desired range by controlling the composition of the hydrogel bead and the tough hydrogel matrix. In particular, it has been confirmed that by combining tough hydrogel having a structure of interpenetrating polymer network (IPN) and hydrogel beads, the physical stability of the membranes can be improved and the elution rate of the moisturizing oil can also be controlled more finely.

• Clean Technology
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• v.7 no.4
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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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• v.29 no.2
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• pp.147-154
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• 2018

Currently, to overcome low therapeutic efficiencies and side effects of anticancer agents, the study of drug carrier based on polymers have been consistently investigated. Although the traditional drug carrier based on polymers displayed an excellent result and significant progress, there has been a problem with the side effect and low therapeutic efficiency because of the premature drug release before reached to the targeted region by the low stability in blood stream and sustained drug release. In this review article, to improve the problem of inefficient drug release, methods were suggested, which can maximize the therapeutic efficiency by increasing the stability in the blood stream and triggering drug release at the target site by introducing a stimuli-responsive substance to the non-toxic and biocompatible natural polymer chitosan.

• Polymer(Korea)
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• v.38 no.1
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• pp.98-102
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• 2014

Nowadays, silk fibroin receives a lot of attention as novel natural biomaterials due to its excellent biocompatibility and biodegradability. Electrohydrodynamic spraying (EHDS) is one of the method for the preparation of micro or nanoparticles by applying high voltage to the polymer solution. In this research, we fabricated silk fibroin porous microparticles by electrohydrodynamic spraying. Poly(ethylene glycol) (PEG) was added to the fibroin solution to give pores to silk fibroin microparticles. By the addition of PEG, the microparticle size was decreased despite of the decrease in conductivity and the increase of viscosity of the spraying solution. It seems that the immiscibility of silk fibroin and PEG affected much more to the microparticle size than the conductivity and viscosity. Immersing the as-sprayed microparticles into the water removed the phase-separated PEG, and finally, porous silk fibroin microparticles were prepared. The porous silk fibroin microparticles are expected to be applied as drug carriers in drug delivery or cell carriers in tissue engineering.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.221-225
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• 2023

Celluloses are naturally occurring polymers that can be easily obtained from various natural sources. Nanocellulose, a form of cellulose, can be derived from regular cellulose and has unique properties that make it ideal for multiple industrial applications. Nanocellulose is a renewable, sustainable, and eco-friendly composite material with exceptional mechanical properties and thermal stability, surpassing metal and ceramic composites. As a result, nanocelluloses are being extensively studied for their potential applications, including fillers, packaging, energy, medicine, and coatings. This review aims to summarize the current research on nanocelluloses and their applications.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.12
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• pp.662-666
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• 2016

This study investigated removal of radionuclides (Cs, Sr) in surface water by coagulation and precipitation. Jar tests were conducted with various chemical and natural coagulants to remove the stabilized radionuclides ($^{133}Cs$, $^{88}Sr$). Chemical coagulants included aluminum sulfate, poly aluminum chloride, and poly aluminum hydroxide chloride silicate (PACS); natural coagulants (minerals) included illite and zeolite. Chemical coagulant alone could achieve removals of Cs and Sr less than 10%; The removals increased up to 23.1% for Cs and 17.8% for Sr with addition of poly-dimethyldiallylammonium chloride (polyDADMAC) along with the chemical coagulants. Compared with chemical coagulants, natural coagulants (minerals) could achieve higher removals of Cs and Sr. Addition of zeolite along with PACS and polyDADMAC increased the removal rates up to 36.9% for Cs and 17.1% for Sr.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.2
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• pp.113-118
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• 2011

This study was aimed to develop blend films by rice by-product (rice-hull and rice-bran) and bio-degradable materials. The rice by-product was firstly prepared from the pulverizing for making fine powder. Bio-degradable materials could be prepared by melting at high temperature. The mixture of the fine powder of rice by-product and melted bio-degradable materials was then blended and cast into films. The obtained films were investigated on their morphology, secondary structures and properties by using SEM, ICP and ASTM, respectively. Mechanical properties and degradability of these films were measured and compared to those of the PE films. Mechanical strength of bio-films was higher than that of PE films, however elongation ratio showed lower percent than that of PE film. In addition, bio-film could be degraded into fragments within 3 months under the field condition of normal upland crop cultivation. Bio-degradable mulching film indicated great potential for agronomic use as a new source of bio-degradable material.