• Title/Summary/Keyword: polyurethane

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3-Methyl-1,5-Pentanediol (MPD)을 함유한 폴리올을 이용한 수분산 폴리우레탄의 합성 및 특성 비교 (Synthesis and Comparison of Properties of Waterborne Polyurethanes Using Polyols Containing 3-Methyl-1,5-Pentanediol (MPD))

  • 김나영;서석훈
    • 접착 및 계면
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    • 제22권2호
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    • pp.39-46
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    • 2021
  • 가지형 구조의 3-Methyl-1,5-pentanediol (MPD)을 함유한 폴리에스테르 폴리올 및 폴리카보네이트 폴리올을 이용하여 수분산 폴리우레탄(WPU)을 합성하였다. 물리적 특성 비교를 위하여 1,4-butanediol (BD)과 adipic acid로부터 얻어진 폴리에스테르 폴리올 및 1,6-hexane diol (HD)/ 1,4-butanediol (BD)로부터 얻어진 폴리카보네이트 폴리올을 이용하여 수분산 폴리우레탄 수지를 합성하였다. 본 연구는 폴리올 분자구조(소프트 세그먼트의 분자구조)가 WPU의 물리적 특성에 미치는 영향을 조사하였으며, MPD가 함유된 폴리올을 이용하여 합성된 WPU의 경우가 MPD를 함유하지 않은 경우보다 100% 탄성률 및 인장 강도는 낮게 나타났으며, 신장률은 높게 나타났다. MPD 성분을 함유한 WPU 필름의 투명도는 MPD 성분을 함유하지 않은 WPU 필름보다 광 투광도가 우수함을 알 수 있었다.

Nanoengineered, cell-derived extracellular matrix influences ECM-related gene expression of mesenchymal stem cells

  • Ozguldez, Hatice O.;Cha, Junghwa;Hong, Yoonmi;Koh, Ilkyoo;Kim, Pilnam
    • 생체재료학회지
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    • 제22권4호
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    • pp.337-345
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    • 2018
  • Background: Human mesenchymal stem cells (hMSCs) are, due to their pluripotency, useful sources of cells for stem cell therapy and tissue regeneration. The phenotypes of hMSCs are strongly influenced by their microenvironment, in particular the extracellular matrix (ECM), the composition and structure of which are important in regulating stem cell fate. In reciprocal manner, the properties of ECM are remodeled by the hMSCs, but the mechanism involved in ECM remodeling by hMSCs under topographical stimulus is unclear. In this study, we therefore examined the effect of nanotopography on the expression of ECM proteins by hMSCs by analyzing the quantity and structure of the ECM on a nanogrooved surface. Methods: To develop the nanoengineered, hMSC-derived ECM, we fabricated the nanogrooves on a coverglass using a UV-curable polyurethane acrylate (PUA). Then, hMSCs were cultivated on the nanogrooves, and the cells at the full confluency were decellularized. To analyze the effect of nanotopography on the hMSCs, the hMSCs were re-seeded on the nanoengineered, hMSC-derived ECM. Results: hMSCs cultured within the nano-engineered hMSC-derived ECM sheet showed a different pattern of expression of ECM proteins from those cultured on ECM-free, nanogrooved surface. Moreover, hMSCs on the nano-engineered ECM sheet had a shorter vinculin length and were less well-aligned than those on the other surface. In addition, the expression pattern of ECM-related genes by hMSCs on the nanoengineered ECM sheet was altered. Interestingly, the expression of genes for osteogenesis-related ECM proteins was downregulated, while that of genes for chondrogenesis-related ECM proteins was upregulated, on the nanoengineered ECM sheet. Conclusions: The nanoengineered ECM influenced the phenotypic features of hMSCs, and that hMSCs can remodel their ECM microenvironment in the presence of a nanostructured ECM to guide differentiation into a specific lineage.

3D 프린팅을 활용한 재료조합에 따른 온습도 변화 분석 (Analysis of Changes in Temperature and Humidity by Material Combination Using 3D Printing)

  • 이희란;김소영;이예진;이옥경
    • 한국의류산업학회지
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    • 제24권1호
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    • pp.127-137
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    • 2022
  • Recently, various clothing items are being developed using 3D printing technology, but comfort has become an issue while wearing them for a long time. Therefore, this study researched on how the temperature and humidity of the devices developed by 3D printing change depending on the material combination. Five types of material combinations (EVA foam, TPU density 10%, TPU density 30%, EVA foam+TPU density 10%, and EVA foam+TPU density 30%) were selected as variables, and the experiment was conducted for two different cases with and without a cover. All the ten types of samples were placed on the hot plate set at 36℃, and the surface temperature and humidity were measured at three different points for 10 minutes. As a result, the case with only TPU showed the greatest temperature change while the case with 100% EVA foam showed the least temperature change. The humidity of the surface layer gradually decreased with time for 100% EVA foam. For the case with TPU materials, the moisture was transferred to the surface layer at first, thereby increasing the humidity but then dropped significantly. Meanwhile, the cases with the cover on showed similar tendencies of change in both temperature and humidity where the overall temperature and humidity delivery were slow.

동작 가변적 3D 프린팅 충격보호패드의 설계 (Design of motion-adaptable 3D printed impact protection pad)

  • 박정현;이진숙;이정란
    • 복식문화연구
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    • 제30권3호
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    • pp.403-413
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    • 2022
  • The purpose of this study was to develop a 3D mesh-type impact protection pad with excellent motion adaptability and functionality by applying 3D printing technology. The hexagonal 3D mesh, which constitutes the basic structure of the pad, comprises two types: small and large. The bridge connecting the basic units was designed as the I-type, V-type, IV-type, and VV-type. After evaluating the characteristics of the bridge, it was found that the V-type bridge had the highest flexibility and tensile elongation. The hip joint pad and knee pad were completed by combining the hexagonal 3D mesh structure with the optimal bridge design. The impact protection pad was printed using a fused deposition modeling-type 3D printer with a filament made of thermoplastic polyurethane material, and the protection pad's performance was evaluated. When an impact force of approximately 6,500N was applied to the pad, the force attenuation percentage was 78%, and when an impact force of approximately 8,000N was applied, the force attenuation percentage was 75%. Through these results, it was confirmed that the 3D-printed impact protection pad with a hexagonal 3D mesh structure connected by a V-shaped bridge developed in this study can adapt to changes in the body surface according to movement and provides excellent impact protection performance.

자외선 경화형 디지털 프린팅을 이용한 3D 프린팅 TPU 소재의 색채 특성 (Color Characteristics of 3D-Printed TPU Material Applied with Ultra-Violet Curable Digital Printing Process)

  • 이선희;박소연;정임주;이정순
    • 한국의류학회지
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    • 제45권6호
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    • pp.1052-1062
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    • 2021
  • This study aims to confirm the possibility of Ultra-Violet (UV)-printed 3D printing materials using thermal polyurethane (TPU) with CMYK colors by applying an eco-friendly UV digital printing process. A UV-printed 3D printing TPU material was prepared with cycles of UV printing and CMYK colors. Dyeability of the 3D TPU samples with cycles of UV printing and CMYK were analyzed for thickness, weight, surface roughness, reflectance, colorimetry, and K/S values. The thickness and weight of 3D-printed TPU samples with cycles of UV printing are increased with overprints from 1 to 5. The surface roughness of 3D-printed TPU samples with increasing UV prints were decreased, meaning that the surface of TPU samples becomes gradually smoother. The reflectance spectra of CMYK UV-printed TPU samples showed the surface reflectance within each characteristic wavelength of CMYK. The 3D-printed TPU samples, subjected to UV printing twice or more, showed low surface reflectance. After examining the L*a*b* of the 3D-printed TPU samples by the cycles of UV printing, the study found that the more UV got printed more than 2 times, the closer the color to each CMYK.

Comparison of 3D accuracy of three different digital intraoral scanners in full-arch implant impressions

  • Ozcan Akkal;Ismail Hakki Korkmaz;Funda Bayindir
    • The Journal of Advanced Prosthodontics
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    • 제15권4호
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    • pp.179-188
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    • 2023
  • PURPOSE. This in vitro study aimed to evaluate the performance of digital intraoral scanners in a completely edentulous patient with angled and parallel implants. MATERIALS AND METHODS. A total of 6 implants were placed at angulations of 0°, 5°, 0°, 0°, 15°, and 0° in regions #36, #34, #32, #42, #44, and #46, respectively, in a completely edentulous mandibular polyurethane model. Then, the study model created by connecting a scan body on the implants was scanned using a model scanner, and a 3D reference model was obtained. Three different intraoral scanners were used for digital impressions (PS group, TR group, and CS group, n = 10 in each group). The distances and angles between the scan bodies in these measurement groups were measured. RESULTS. While the Primescan (PS) impression group had the highest accuracy with 38 ㎛, the values of 104 ㎛ and 171 ㎛ were obtained with Trios 4 IOSs (TR) and Carestream 3600 (CS), respectively (P = .001). The CS scanner constituted the impression group with the highest deviation in terms of accuracy. In terms of dimensional differences in the angle parameter, a statistically significant difference was revealed among the mean deviation angle values according to the scanners (P < .001). While the lowest angular deviation was obtained with the PS impression group with 0.185°, the values of 0.499° and 1.250° were obtained with TR and CS, respectively. No statistically significant difference was detected among the impression groups in terms of precision values (P > .05). CONCLUSION. A statistically significant difference was found among the three digital impression groups upon comparing the impression accuracy. Implant angulation affected the impression accuracy of the digital impression groups. The most accurate impressions in terms of both distance and angle deviation were obtained with the PS impression group.

여군 전투복 내 관절 부위 보호 패드 개발을 위한 설계 변인 조합에 따른 물성 평가 (Evaluation of Physical Properties of Material Combination for Fabricating Protection Pads for Women's Army Combat Uniforms )

  • 이옥경;이희란;김소영;이예진
    • 한국의류학회지
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    • 제47권2호
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    • pp.311-322
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    • 2023
  • In this study, the properties of various material combinations were evaluated and an ideal material for fabricating protection pads for women's army combat uniforms was determined. Eight specimens were used for the evaluation: two types of materials, namely thermoplastic polyurethane for 3D printing, T and ethylene-vinyl acetate, E; two infill densities, namely 10%, 10 and 30%, 30; two types of pad designs, i.e., without holes, A and with holes, B; 2×2×2=8 and control E. The tensile strength, flexural strength, impact absorption, and weight of these specimens were evaluated. Results revealed that E was the most flexible material; however, its tensile strength and impact absorption were very low. Protection pads made from T (T-10A, T-10B, T-30A, and T-30B) had excellent tensile strength and impact absorption; however, they had low performance in ease of movement. Alternatively, protection pad with holes and an infill density of 30% produced using a combination of T and E had a high initial tensile modulus and exhibited excellent impact absorption. Moreover, it was flexible and light, which satisfies the standards and conditions required by protection pads. However, if T-E-10A and T-E-30B exhibited low impact absorption, as required, they can be regarded as appropriate materials for protection pads.

공항용 조인트 충진재의 성능 및 내유저항특성 비교연구 (Comparison of Performance & Jet Fuel Oil Resistance of Joint Sealant Materials for Airside)

  • 박태순;이근식;이수희
    • 대한토목학회논문집
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    • 제26권4D호
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    • pp.587-592
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    • 2006
  • Airside 지역 콘크리트 포장의 조인트에 사용되는 충진재는 항공기 이 착륙시 엔진에서 뿜어져 나오는 고열의 후폭풍과 계류장에서 항공기의 정비 및 주유시 항공유 유출에 대한 저항성을 가지고 있어야 한다. 이러한 특성 때문에 공항용 조인트 충진재는 도로포장용과는 다른 충진재의 사용이 요구되고 있다. 본 연구에서는 국내외에서 사용되고 있는 3 종류의 충진재에 대하여 물리적 특성 시험과 성능시험을 실시하였다. 시험재료는 폴리썰파이드, 폴리우레탄, 실리콘을 사용하였다. 시험결과 폴리썰파이드 충진재는 내열성과 내유성에 대한 저항성이 가장 우수하였으며, 폴리우레탄, 실리콘 충진재의 순으로 시험결과가 나타났다. Airside 지역별 특성을 고려했을 때, 폴리썰파이트 충진재는 활주로와 계류장에, 폴리우레탄 충진재는 유도로에 사용하는 것이 적절하며 실리콘 충진재는 Airside 지역 충진재로는 부적합한 것으로 나타났다.

폼 충전 FRP 바닥판의 약축방향 정적거동 특성에 관한 실험적 연구 (An Experimental Study on the Static Behavior in Weak Axis of FRP Bridge Deck Filled with a Foam)

  • 김병민;지광습;황윤국;이영호
    • 대한토목학회논문집
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    • 제26권6A호
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    • pp.943-953
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    • 2006
  • 본 연구에서는 섬유강화 플라스틱(FRP) 소재로 제작된 사각형 중공 교량 바닥판의 약축방향 거동을 보완하기 위해서 바닥판의 중공 내부를 구조용 폼(foam)으로 충전하였다. 충전폼의 유무와 폼의 강도에 따른 약축방향 정적거동 특성을 실험적으로 분석하여 충전폼의 역할을 검토하였다. FRP에 비하여 탄성계수가 현저히 낮은 구조용 폼으로 바닥판 내부를 충전하여 도 본래의 경량성을 유지하면서 공칭강도, 강성 등의 횡방향 구조성능이 획기적으로 개선되었다. 웨브의 개수에 따른 파괴거동을 비교하여 내부충전 FRP 바닥판에서 웨브의 역할을 파악하였다. 웨브가 내부충전 FRP 바닥판의 약축방향 강도에 미치는 영향은 미미하였으나, 폼 내부에서 발생한 균열의 전파를 차단함으로써 파괴모드의 취성을 경감시켰다.

부분층화상을 입은 외래 환자에서 이부프로펜 방출성 드레싱 제재(Biatain Ibu®)의 창상부위 통증의 경감 효과에 대한 연구 (Pain Relief Efficacy of Ibuprofen Releasing Foam Dressing (Biatain Ibu®) on Outpatient Patient with Partial Thickness Burn Wound)

  • 이준호;최봉규;이진호;김재원
    • 대한화상학회지
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    • 제22권1호
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    • pp.15-19
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    • 2019
  • Purpose: Pain management in burn treatment is important in improving wound healing and quality of life. Ibuprofen is a proven pain relieving agent in patients with partial thickness burn by intraveous injection. The purpose of this study is to evaluate the efficacy of Biatain Ibu® (polyurethane foam containing ibuprofen) in pain control for outpatients with partial thickness burns. Methods: A prospective randomized clinical trial was performed in outpatients with partial thickness burn from August 1, 2017 to July 31, 2018. Acute pain, chronic pain, complications, days for re-epithelialization and patient's satisfaction were compared between Biatain Ibu® and Biatain® groups. Results: A total of 20 patients (Biatain Ibu®, n=10; Biatain®, n=10) were assessed in the trial. On Burn days 3, 5, 7, 11, 13, and 15, the acute pain levels were significantly lower in the Biatain Ibu® group than in the Biatain® group. Complications, chronic pain levels and days for re-epithelialization were not significantly different between the two groups. Patient's satisfaction was not statistically significant but was higher in the Biatain Ibu® group. Conclusion: Biatain Ibu® is effective in relieving pain in outpatients with partial thickness burn without decreasing patient satisfaction, wound healing ability or developing any complications.