• Title/Summary/Keyword: bio-degradable

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Porous Bio-degradable Nano-fiber Machining by Femtosecond Laser (다공성 친바이오 나노섬유 극초단 레이저 가공특성 연구)

  • Choi, Hae-Woon
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.3
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    • pp.339-345
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    • 2012
  • Electrospun meshed poly-caprolactone PCL was patterned by femtosecond laser with linear grooves. As parametric variables, focus spot size, pulse energy, and scanning speed were varied to determine the affects on groove size and the characteristics of the electrospun fiber at the edges of these grooves. The femtosecond laser was seen to be an effective means for flexibly structuring the surface of ES PCL scaffolds and the width of the ablated grooves was well controlled by laser energy and focus spot size. The ablation threshold was measured to be $14.9J/cm^2$ which is a little higher than other polymers. These affects were attributed to optical multiple reflections inside nano-fibers. By the laser-induced plasma at higher pulse energies, some melting of fibers was observed.

Bio-degradable 3D-scaffold fabrication using rapid-prototyping system (쾌속조형시스템을 이용한 생체 조직 재생용 지지체 제작과 특성분석)

  • Kim, Ji-Woong;Park, Ko-Eun;Lee, Jun-Hee;Park, Su-A;Kim, Wan-Doo
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1697-1699
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    • 2008
  • The purpose of tissue engineering is to repair or replace damaged tissues or organs by a combination of cells, scaffold, suitable biochemical and physio-chemical factors. Among the three components, the biodegradable scaffold plays an important role in cell attachment and migration. In this study, we designed 3D porous scaffold by Rapid Prototyping (RP) system and fabricated layer-by-layer 3D structure using Polycarprolactone (PCL) - one of the most flexible biodegradable polymer. Furthermore, the physical and mechanical properties of the scaffolds were evaluated by changing the pore size and the strand diameter of the scaffold. We changed nozzle diameter (strand diameter) and strand to strand distance (pore size) to find the effect on the mechanical property of the scaffold. And the surface morphology, inner structure and storage modulus of PCL scaffold were analyzed with SEM, Micro-CT and DMA.

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A Study of PCL and PET ablation by ultrashort laser (극초단 레이저를 이용한 PCL 및 PET 가공에 대한 연구)

  • Choi, Hae-Woon;Shin, Hyun-Myung
    • Laser Solutions
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    • v.11 no.4
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    • pp.1-6
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    • 2008
  • This paper describes microscale laser structuring of electrospun(ES) PCL and PET nanofiber meshes. Electrospinning produces non-woven meshes of synthetic or natural materials fibers with diameters ranging from micron down to the nanometer scales that are advantageous for the supporting the growth of the small scale structures. Ultrashort laser found to be effective on the fabrication of engineeredtissue scaffold with minimum heat affect and ultra precision ablation patterns. The affect of energy range for ablation quality was analyzed and ablation characteristics of PCL and PET were compared.

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Synthesis of Cyclic Type Semi-Fluorinated Disodium Alkanesulfonate

  • Chirumarry, Sridhar;Ko, Yohan;Jang, Kiwan;Shin, Dong-Soo
    • Journal of the Korean Chemical Society
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    • v.60 no.4
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    • pp.257-260
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    • 2016
  • A new perfluorobutyl substituted cyclic type disodium alkanesulfonate is designed, synthesized and characterized as alternative substance to perfluorooctane sulfonic acid (PFOS, 1), a well-known surfactant. Cylic type sulfonate was accomplished from commercially available 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol in four steps. Bio-degradable perfluorobutyl moiety was introduced from fluorous diol, which is symmetrically substituted amphiphile via installation of an intermediate trifluoromethanesulfonyl ester and easily manipulated by double displacement of triflate using potassium malonate and further reduction followed by nucleophilic ring opening are key reactions to get target disodium alkanesulfonate. The efficiency and simplicity in the synthesis of this material offer a new strategy to design PFOS alternatives.

Preparation of Tuna Skin Byproduct Film Containing Pinus thunbergii Cone Extract

  • Bak, Jing-Gi;Kim, Jin;Ohk, Seung-Ho
    • Biomedical Science Letters
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    • v.26 no.4
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    • pp.360-367
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    • 2020
  • Tuna skin byproduct extract (TSB) was used as a biocompatibility film base material, and its composite film with gellan gum (GG) was prepared. In addition, Pinus thunbergii cone extract (PTCE) was incorporated into the film to provide anti-oxidant and anti-bacteria activities. The tensile strength (TS) of the TSB/GG composite films increased with increasing GG content, whereas elongation at break (E) decreased. TSB/GG film at a ratio of 0.5:0.5 (w/w) showed the most desirable TS and E values. Based on scavenging free radical potentials and disc diffusion method results against growth of bacteria, antioxidant and anti-bacteria activities of films increased with increasing PTCE concentration. Accordingly, this study showed that TSB/GG could be used as a film material while the TSB/GG composite film containing PTCE can be utilized as functional packaging.

A Study on the Fabrication and Mechanical Properties Evaluation of Natural Fiber Composites added Eco-friendly Materials (친환경 소재를 첨가한 천연섬유 복합재의 제조 및 기계적 물성 평가 연구)

  • Kim, Jae-Cheol;Lee, Dong-Woo;Prabhakar, M.N.;Song, Jung-Il
    • Composites Research
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    • v.33 no.4
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    • pp.213-219
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    • 2020
  • Recently, global facing environmental issues have been raised caused by plastic waste. Hence, increasing the demand for interest in environmentally friendly materials. In this row, research on engineering composite materials also replacing the synthetic reinforcement by introducing natural fibers. However, focus on the strength and interfacial adhesion between matrix and reinforcement is very essential in natural fiber composite, which is insufficient in the literature. There are number of approaches for improving the mechanical strength of the composites, one of the common methods is to reinforce additive nanoparticles. The present investigation, bio-additives were synthesized utilizing bio-waste, cheap, bio-degradable sea-weed powder that could replace expensive nanomaterials and reinforced into the CFRP composite through Hand lay-up followed by a vacuum process. Mechanical properties were evaluated and analyzed through microanalysis. The results concluded that synthesized additives are effective for improving mechanical properties such as tensile, flexural, impact, and shear strength. Overall, the results confirmed that the fabricated composites have potential applications in the field of engineering applications.

Development of Biodegradable Polymeric Membrane for Interventional Procedure: Preliminary Study (인터벤션 시술을 위한 생분해성 고분자막의 개발 : 예비연구)

  • Bang, Jung-Wan;Hyun, Chang-Yong;Kim, Tae-Hyung;So, Woon-Young;Kim, Jin-Tae;Kim, Sang-Sub;Jung, Hee Dong;Heo, Yeong Cheol
    • Journal of radiological science and technology
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    • v.37 no.1
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    • pp.15-20
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    • 2014
  • This study was to evaluate clinical feasibility of biodegradable polymeric membrane for interventional procedure in preliminary study. Bio-degradable polymetric membrane was produced into a solution by mixing hyaluronic acid powder with NaOH solution in a heating mantle. Three different concentrations of contrast media (10, 20, and 30 vol%) were added to the produced soluble powder, and vertical agitation was performed for 12 hours at a speed of 100 to 200 rpm at a room temperature. It was freeze dried for 24 hours at a temperature $80^{\circ}C$. Pressure on the freeze dried sample was exerted by a hydraulic press in order to form the freeze dried sample into a membrane. The membrane produced with varying contrast medium concentration was visually examined by a scanning electron microscope and radiographically inspected. Under the visual examination, the higher the concentration of contrast medium, the rougher the surface. Radiographic transparency was similar under all conditions of fluoroscopic radiography, simple radiography, and serial radiography. In conclusion, this preliminary study verified that bio-degradable membrane produced with hyaluronic acid was a material with clinical usability.

Study on the Improving Thermal and Mechanical Properties of Eco-friendly Materials used for Training Ammunition (연습용 탄약 친환경 재료의 내열성 및 기계적 특성 향상에 관한 연구)

  • Kim, Myung-Hyun;Shon, Byoung-Chul;Lee, Young-Tae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.5
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    • pp.557-562
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    • 2018
  • Unlike live ammunition which has killing power due to the use of high explosives, training ammunition has only the limited explosive effect needed for training purposes, so the risk of accidents is lowered. Because training ammunition is used in large quantities during military drills, the problem of environmental pollution occurs. As most of the waste is left out in the training field, using bio-degradable polymers such as Polylactic Acid (PLA) can provide a solution to these environmental issues. However, bio-degradable polymers such as PLA usually have poor thermal and mechanical properties compared with other general purpose polymers, so they need to be improved before they can be used for military purposes. In this study, Talc is added to the PLA used for the parts of Training Grenades to improve some of their properties and the changes of their thermal and mechanical properties were verified. In the case of the 1 wt.% ~ 5 wt.% PLA/Talc blends, the thermal properties were improved in proportion to the content of Talc, but the best mechanical properties were observed for the 1 wt.% and 3 wt.% PLA/Talc blends.

Prospect for 3D Printing Technology in Medical, Dental, and Pediatric Dental Field (의료 3D 프린팅 기술의 전망 및 소아치과분야에서의 활용)

  • Lee, Sangho
    • Journal of the korean academy of Pediatric Dentistry
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    • v.43 no.1
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    • pp.93-108
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    • 2016
  • One of the fields to which the 3D printing technology can be applied is the field of medicine. Recently, the application of 3D printing technology to the bio-medical field has been gradually increasing with the commercializing of the bio-compatible or bio-degradable materials. The technology is currently contributing to the biomedical field by reducing times required for operations or minimizing adverse effects through preoperative identification of post-surgical consequences or model surgery with artificial bones and organs. This technology also enables the production of customized biomedical auxiliary products like hearing aids or artificial legs etc. For the field of dentistry, the 3D printing technology is also expected to elevate the level of dental treatment by making the customized orthodontic models, crown, bridge, inlay, and surgical guides for implant and surgery. However, issues remaining unidentified or incomplete in printing materials, modeling technology, software technology associated with CAD, verification of bio-stability and bio-effectiveness of materials or in compatibility and standardization of the technology are yet to be solved or be clarified for the full-scale application of the 3D printing technology, thus, it seems such issues should be resolved through further studies.

Characteristics of LED Lighting Device Using Heat Sinks of 7.5 W CMP-PLA (7.5 W CMP-PLA 방열판을 적용한 LED 등기구 특성)

  • Kim, Young-Gon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.12
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    • pp.920-923
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    • 2013
  • In this paper, the characteristics of a carbon nanotube composite heat sink proposed to replace the advanced Al heat sinks for LED lighting devices were studied. Proposed CMP-PLA heat sink was made by mixing 20~70 wt% carbon nanotube, 20~70 wt% bio-degradable polymer of melt-blended PLA (poly lactic acid) and PBS (poly butylene succinate) and PLA nucleating agents composed of the mixture of soybean oil and biotites, at $150{\sim}220^{\circ}C$ with 1,000~1,500 rpm. Optical and electric characteristics of 7.5 W LED lighting devices using heat sinks with such prepared CMP-PLA were investigated. And, the properties of the heat, which was not released from the CMP-PLA type heat sinks, was also investigated. The color temperature of LED lighting devices using the CMP-PLA heat sinks was 5,956 K, which is x= 0.32 and y= 0.34 in the XY chromaticity, and the color rendering index was 75. The luminous flux and the luminous efficiency of LED lighting devices using the CMP-PLA heat sinks was 540.6 lm and 72.68 lm/W respectively. Measured initial temperature of the heat sinks was $27^{\circ}C$, and their temperature increased as time to be saturated at $52^{\circ}C$ after an hour.