• 한국의류학회지
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• 제48권2호
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• pp.312-327
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• 2024

In this study, a rehabilitation 3D printed wearable device was developed by combining an assembly-type robot hand and an integral-type robot hand through fused deposition 3D printing manufacturing with various hardness TPU (Thermoplastic Polyurethane) filaments. The hardware configuration of the robot hand includes a controller designed with four motors, one small servo motor, and a circuit board. In the case of the assembly-type robot hand model, a 3D printed robot hand was assembled using samples printed with TPU of hardness 87A and 95A. It was observed that TPU with a hardness of 95A was suitable for use due to shape stability. For the integrated-type robot hand model, the external sample using TPU of hardness 95A could be modified through a cutting method, and the hardware configuration is the same as the assembly-type. The system structure of the 3D printed robot hand was improved from an individual control method to a simultaneous transmission method.Furthermore, the system architecture of an integrated 3D printed robotic hand rehabilitation device and the application of the rehabilitation device were developed.

• Journal of Advanced Marine Engineering and Technology
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• 제39권1호
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• pp.99-104
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• 2015

현재 국내에서 사용되고 있는 구명뗏목은 국제항해 선박용으로 SOLAS 협약 규정에 적합하도록 개발된 제품이며, 20m 미만의 소형어선이나 레저선박, 평수구역을 항해하는 화물선에 적합한 크기와 용도로 개발된 제품은 전무한 실정이다. 그러나 선진국에서는 이러한 소형선박 및 연안 선박에 적용하기 위한 자국 규정을 개발하거나 ISO 9650에 충족하는 구명뗏목을 개발하여 보급하고 있으며, 열가소성 폴리우레탄(Thermoplastic polyurethane, TPU) 등 경량화 소재와 열접착(Heat sealing), 고주파접착(Radio-frequency welding, RFW) 등의 경제적인 생산방법을 적용하여 성능이 우수한 제품을 시장에 보급함으로써 이들 선박의 인명안전에 기여하고 있는 상황이다. 본 논문에서는 소형선박의 해양사고 시 인명피해 저감을 위한 방안으로 경량화된 열가소성 폴리우레탄 재료를 사용하고 고주파 접착 등의 제조공법을 이용하여 소형선박용 구명뗏목을 개발한 내용을 소개하고자 한다.

• Advances in nano research
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• 제10권1호
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• pp.59-69
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• 2021

Electrospinning is a cost-effective and versatile method for producing submicron fibers. Although this method is relatively simple, at the theoretical level the interactions between process parameters and their influence on the fiber morphology are not yet fully understood. In this paper, the aim was finding optimal electrospinning parameters in order to obtain the smallest fiber diameter by using Taguchi's methodology. The nanofibers produced by electrospinning a solution of Thermoplastic Polyurethane (TPU) in Dimethylformamide (DMF). Polymer concentration and process parameters were considered as the effective factors. Taguchi's L9 orthogonal design (4 parameters, 3 levels) was applied to the experiential design. Optimal electrospinning conditions were determined using the signal-to-noise (S/N) ratio with Minitab 17 software. The morphology of the nanofibers was studied by a Scanning Electron Microscope (SEM). Thereafter, a tensile tester machine was used to assess mechanical properties of nanofibrous scaffolds. The analysis of DoE experiments showed that TPU concentration was the most significant parameter. An optimum combination to reach smallest diameters was yielded at 12 wt% polymer concentration, 16 kV of the supply voltage, 0.1 ml/h feed rate and 15 cm tip-to-distance. An empirical model was extracted and verified using confirmation test. The average diameter of nanofibers at the optimum conditions was in the range of 242.10 to 257.92 nm at a confidence level 95% which was in close agreement with the predicted value by the Taguchi technique. Also, the mechanical properties increased with decreasing fibers diameter. This study demonstrated Taguchi method was successfully applied to the optimization of electrospinning conditions for TPU nanofibers and the presented scaffold can mimic the structure of Extracellular Matrix (ECM).

• Elastomers and Composites
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• 제54권3호
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• pp.225-231
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• 2019

Bio-based polyester polyol was synthesized via esterification between azelaic acid and isosorbide. After esterification, bio-based polyurethanes were synthesized using polyester polyol, 1,3-propanediol as the chain extender, and 4,4'-diphenylmethane diisocyanate, in mixing ratios of 1:1:1.5, 1:1:1.8, 1:1:2, and 1:1:2.3. The bio TPU (Thermoplastic Polyurethane) samples were characterized by using FT-IR (Fourier Transform Infrared Spectroscopy), TGA (Thermal Gravimetric Analysis), DSC (Differential Scanning Calorimetry), and GPC (Gel Permeation Chromatography). The mechanical properties (tensile stress and hardness) were obtained by using UTM, a Shore A tester, and a Taber abrasion tester. The viscoelastic properties were tested by an Rubber Processing Analyzer in dynamic strain sweep and dynamic frequency test modes. The chemical resistance was tested with methanol by using the swelling test method. Based on these results, the bio TPU synthesized with the ratio of 1:1:2.3, referred to as TPU 4, showed the highest thermal decomposition temperature, the largest molecular weight, and most compact matrix structure due to the highest ratio of the hard segment in the molecular structure. It also presented the highest tensile strength, the largest elongation, and the best viscoelastic properties among the different bio TPUs synthesized herein.

• Composites Research
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• 제30권3호
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• pp.181-187
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• 2017

나노 및 마이크로 크기의 철(Fe), 마그네타이트($Fe_3O_4$) 및 니켈(Ni) 입자가 분산된 열가소성 폴리우레탄(TPU) 접착필름에서 각 금속의 크기 및 형상 그리고 피착재의 종류에 따른 접착필름의 유도가열 거동을 연구하였다. 연구결과 동일한 첨가량 및 유사한 입자 크기에서 철과 니켈이 분산된 열가소성 TPU 접착필름에 비해 마그네타이트가 분산된 TPU 접착필름의 발열이 높게 나타났다. 철과 니켈의 입자 크기가 자기장의 표면 침투 깊이(Penetration skin depth) 보다 클 경우 와전류에 의한 발열로 인해 입자 크기가 커질수록 초기 승온속도와 최고 온도가 증가하는 것을 확인하였다. 서로 다른 형태를 갖는 니켈 입자를 사용한 유도가열 실험 결과 편상(flake)의 입자가 TPU 접착필름에 분산되었을 때 자기이력(Magnetic hysteresis)에 의한 열 발생으로 가장 높은 발열이 나타남을 알 수 있었다. 또한 금속 입자가 분산된 TPU 접착필름이 서로 다른 피착재에 적용되었을 때 발열현상이 상이하게 나타났으며 피착재의 열전도도에 따른 결과를 확인하였다.

• 한국염색가공학회지
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• 제35권1호
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• pp.20-28
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• 2023

In this study, TPU resin for coating was prepared by varying the mixing ratio of antistatic TPU and recycled TPU to manufacture permanent antistatic materials. The coated yarn was prepared by coating on the nylon yarn, and then the thermal, rheological, mechanical properties and antistatic properties were analyzed. In addition, antistatic properties and durability were confirmed after manufacturing UD fabrics using coated yarns. The mixing ratio of antistatic TPU and recycled TPU was most appropriate at 4:6, and the antistatic property had a surface resistance of 2.20 × 10⁹ Ω and a static charge of 398 V. In the coating process, the coating speed was most appropriate at 0.21 m/s, and the surface resistance of the UD fabric manufactured with the coated yarn manufactured under this condition was 6.80 × 10⁹ Ω and the static charge was 484 V. The UD fabric had a surface resistance of 7.21 × 10⁹ Ω and a static charge of 517 V after washing 10 times, and it was confirmed that the permanent antistatic property was excellent.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2008년도 제39차 학술발표회
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• pp.149-150
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• 2008

인체에 무해한 친환경 소재인 TPU수지를 인조합성피혁에 채용하여 기존에는 없던 통기성을 부여하였으며 PU 소재의 제품보다 내가수분해성이 뛰어나면서 기본물성이 우수한 고감성 인조합성 피혁 제품을 개발하였다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2002년도 봄 학술발표회 논문집
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• pp.243-246
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• 2002

자동차 차체 제작을 위해서는 차체의 견고성과 승객의 안전성을 동시에 고려하여 너무 강하거나 너무 무르지 않은 재질의 선택과 차체 설계의 최적화가 요구된다. 본 논문에서는 차량 충돌 시 자동차의 안전도를 향상시키면서 차량의 손상을 최소화 함으로써 수리비를 절감하기 위한 목적으로 TPU(Thermoplastic Polyurethane Elastomer)에 공기를 채워서 만든 에어백 자동차 범퍼를 개발하였다. (중략)

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2006년도 임시총회 및 추계학술발표회
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• pp.78-81
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• 2006

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2003년도 춘계학술대회 논문집
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• pp.162-166
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• 2003

탄성체는 크게 열경화성 탄성체(thermosetting elastomer)와 열가소성 탄성체(thermoplastic elastomer)로 분류할 수 있다. 이러한 탄성체들 가운데 대표적인 소재로 반복하여 재사용이 가능하여 경제적인 소재이며 환경친화적인 소재인 열가소성 폴리우레탄에 대한 관심이 높아져 왔고 그에 따른 연구도 활발히 진행되어 왔다. 이러한 열가소성 폴리우레탄(TPU)은 가공의 용이성과 양호한 물리적 ㆍ화학적 성질 때문에 섬유용 소재에서 엔지니어링 플라스틱에 이르기까지 광범위한 산업용 소재로의 개발을 통하여 사용량이 지속적으로 증가를 보이고 있다. (중략)