• 공업화학
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• 제24권3호
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• pp.305-313
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• 2013

본 연구는 glycidyl azide polymer (GAP)계 에너지 함유 열가소성 폴리우레탄 탄성체(energetic thermoplastic polyurethane elastomers, ETPE)를 합성한 후 탄성체의 필름 제조 공정의 열처리 조건이 물성에 미치는 영향에 대하여 고찰하였다. GAP계 ETPE는 ATR-FTIR, DSC, 그리고 DMA를 이용하여 분석하였다. GAP계 ETPE의 물성에 대한 열처리 조건의 영향은 $80{\sim}130^{\circ}C$의 온도 범위에서 1 h과 24 h의 열처리 시간을 나누어 연구를 진행하였다. 1 h의 열처리 조건에서는 $130^{\circ}C$의 열처리 온도에서 그리고 24 h의 열처리 과정에서는 $105^{\circ}C$ 이상의 온도조건에서 아자이드기의 흡수대인 $2090cm^{-1}$ 피크의 감소가 관찰되었으며, methylene chloride와 dimethylformamide 용매에 대한 필름의 용해도 또한 감소하였다. 이것은 $100^{\circ}C$ 이상 열처리 온도조건이 아자이드기의 가교 부반응을 유도할 수 있음을 나타낸다. 또한 열처리 온도가 $80^{\circ}C$에서 $110^{\circ}C$로 증가함에 따라 온도변화에 따른 저장 탄성률 곡선의 고온 고무평탄 영역이 더 높은 온도까지 확장되었으며, 이 또한 가교반응의 결과이다.

• 청정기술
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• 제14권1호
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• pp.29-34
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• 2008

폴리올 주 사슬에 에스테르기를 도입하기 위한 방법으로 산화프로필렌 (propylene oxide, PO)과 무수 프탈산(phthalic anhydride, PA)의 공중합을 이중금속 시안염 촉매 존재 하에서 수행하였다. 이중금속 시안염 촉매는 이 공중합에 매우 효율적인 촉매임을 알 수 있었으며, 이 공중합에 대한 반응성비는 변형 Kelen $T{\ddot{u}}d{\ddot{o}}s$ 식을 이용하여 구한 결과 $r_1(PA)\;=\;0$, $r^2(PO)\;=\;0.248$이었다. 주 사슬에 함유되어 있는 PA의 함량이 1.0, 2.1, 7.52, 11.42 mol%인 4가지 폴리을 시료를 이용하여 경질부 함량이 19 wt%인 열가소성 폴리우레탄을 제조하였다. PA의 함량이 증가할수록 신율은 낮아졌으며, 인장강도와 인장탄성율은 증가하는 경향을 보였다. PO와 PA를 공중합 하여 폴리올에 도입되는 PA의 함량을 조절함으로써 결과적으로 폴리우레탄의 물성을 조절할 수 있음을 알 수 있었다.

• 한국의류산업학회지
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• 제24권3호
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• pp.333-345
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• 2022

This study developed and evaluated the motion control of 3D printed fingers applied to smart gloves. Four motions were programmed by assembling the module using the Arduino program: cylindrical grasping, spherical grasping, tip-to-tip pinch gripping, and three-jaw pinch gripping. Cap and re-entrant (RE) strip types were designed to model the finger. Two types of modeling were printed using filaments of thermoplastic elastomer (TPE) and thermoplastic polyurethane (TPU). The prepared samples were evaluated using three types of pens for cylidrical grasping, three types of balls for spherical grasping, and two types of cards for tip-to-tip pinch gripping and three-jaw pinch gripping. The motion control of fingers was connected using five servo motors to the number of each control board. Cylindrical and spherical grasping were moved by controlling the fingers at 180° and 150°, respectively. Pinch gripping was controlled using a tip-to-tip pinch motion controlled by the thumb at 30° and index-middle at 0° besides a three-jaw pinch motion controlled by the thumb-index finger-middle at 30°, 0°, and 0°, respectively. As a result of the functional evaluation, the TPE of 3D-printed fingers was more flexible than those of TPU. RE strip type of 3D-printed fingers was more suitable for the motion control of fingers than the 3D-printed finger.

• 한국기계가공학회지
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• 제17권3호
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• pp.120-126
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• 2018

In the present study, the multi-nozzle electrospinning process is investigated for the fabrication of uniform polymer nanofiber mats. Electrospinning has been one of the simple and efficient methods to manufacture polymer nanofibers and their mats. Although a typical electrospinning has many advantages such as simple system and operation, various materials, and cost-effectiveness, a relatively low productivity prevents it from being used in practical applications. Thus, the multi-nozzle electrospinning system with the adjustable nozzle position and rotating drum collector is designed and produced in this study. In particular, the effects of the inter-nozzle distance and spatial arrangement of nozzles on the uniformity of the electrospun nanofibers are investigated. With this multi-nozzle electrospinning process, the maximum flow rate of the supplied polymer solution for a uniform electrospinning increases, which indicates the enhanced productivity.

• 패션비즈니스
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• 제22권4호
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• pp.93-105
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• 2018

Using FDM 3D printing, yarn shape and composition were modeled and 3D printed with PLA and TPU filaments currently used for apparel. Based on this, mechanical characteristics were measured to determine 3D printing yarn according to type of filaments in the 3D printed output and deformation and recovery characteristics due to differences in structure type. As a result of examining tensile and shear characteristics of PLA and TPU 3D printing compiles, TPU overall was measured with significantly lower stress than PLA. This is due to high elasticity of TPU's character, revealing that it has better flexibility than PLA. In addition, during deformation due to external forces, the more freedom between the head and foot parts of the loop, and the lower the force associated with each other, the more flexible it is. TPU revealed that it was easier to tension and recovery from tensile deformation than PLA, indicating potential for clothing materials using 3D printing. If high-molecular materials, such as PLA flexibility, it is likely to provide some flexibility through development of styles, including degree of freedom in modeling. Based on this, we provide basic data for developing 3D printing textures that can be satisfied with textile for apparel.

• 한국군사과학기술학회지
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• 제12권5호
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• pp.660-666
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• 2009

Thermoplastic polyurethane elastomer(PU-TPE) and energetic thermoplastic polyurethane Elastomer(E-PU-TPE) were prepared from Hexamethylene diisocyanate(HDI), 1,4-BD/AA ester polyol and glycidyl azide polymer(GAP-2400) as an energetic material by the addition polymerization. The PU-TPE and E-PU-TPE were characterized by FT-IR and GPC. Viscometer, DSC and UTM were used to investigate the viscose behavior with a various solvent, thermal properties and mechanical properties of PU-TPE and E-PU-TPE, which are of potential interest for the development of high performance binder of energetic solid propellants. It was found that $M_w$ of PU-TPE and E-PU-TPEs are over 100,000 and decreased with increase of GAP-2400 contents. $T_m$ and ${\Delta}H$ as thermal properties decreased and also tensile strength and elongation at break as mechanical properties decreased with increase of GAP-2400 contents.

• 한국의류학회지
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• 제46권3호
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• pp.481-493
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• 2022

This study investigated process conditions for 3D printing through manufacturing thermoplastic polyurethane (TPU) samples under different infill conditions. Samples were prepared using a fused deposition modeling 3D printer and TPU filament. 12 infill patterns were set (2D: grid, lines, zigzag; 3D: triangles, cubic, cubic subdivision, octet, quarter cubic; 3DF: concentric, cross 3D, cross, honeycomb), with 3 infill densities (20%, 50%, 80%). Morphology, actual time/weight and compressive properties were analyzed. In morphology: it was found that, as infill density increased, the increase rate of the number of units rose for 2D and fell for 3DF. Printing time varied with the number of nozzle movements. In the 3DF case, the number of nozzle movements increased rapidly with infill density. Sample weight increased similarly. However, where the increase rate of the number of units was low, sample weight was also low. In compressive properties: compressive stress increased with infill density and stress was high for the patterns with layers of the same shape.

• 한국의류산업학회지
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• 제24권6호
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• pp.812-824
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• 2022

This study proposes to develop a 3D printed re-entrant(RE) strip by shape memory thermoplastic polyurethane that can be deformed and recovered by thermal stimulation. The most suitable 3D printing infill density condition and temperature condition during shape recovery for mechanical behavior were confirmed. As the poisson's ratio indicated, the higher the recovery temperature, the closer the poisson's ratio to zero and the better the auxetic properties. After recovery testing for five minutes, it appeared that the shape recovery ratio was the highest at 70℃. The temperature range when the shape recovery ratio appeared to be more than 90% was a recovery temperature of more than 50℃ and 60℃ when deformed under a constant load of 100 gf and 300 gf, respectively. This indicated that further deformation occurred after maximum recovery when recovered at a temperature of 80℃, which is above the glass transition temperature range. As for REstrip by infill density, a shape recovery properties of 100% was superior than 50%. Additionally, as the re-entrant structure exhibited a shape recovery ratio of more than 90%, and exhibited auxetic properties. It was confirmed that the infill density condition of 100% and the temperature condition of 70℃ are suitable for REstrips for applying the actuator.

• 공업화학
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• 제30권6호
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• pp.673-680
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• 2019

GAP 및 GAP-co-BO계 에너지 함유 열가소성 탄성체(ETPE)의 하드세그먼트 함량을 30~45% 범위에서 변화시켜 합성하여 열적 특성 및 기계적 특성을 비교 연구하여 고찰하였다. FTIR 분석 결과로부터 GAP-co-BO계 ETPE와 GAP계 ETPE는 하드세그먼트 함량이 증가함에 따라 수소결합을 형성하는 능력이 증가하였으며 GAP-co-BO계 ETPE의 수소 결합 능력이 GAP계 ETPE보다 크게 나타났다. DSC와 DMA 분석 결과로부터 GAP계 ETPE의 유리전이온도(T_g)는 하드세그먼트 함량이 증가함에 따라 증가하였으나, GAP-co-BO계 ETPE의 유리전이온도(T_g)는 하드세그먼트가 증가하여도 유사한 값을 유지하였다. 상온 storage modulus는 GAP-co-BO계 ETPE의 값이 GAP계 ETPE 값보다 더 크게 나타났다. 이러한 거동은 GAP-co-BO계 ETPE 내의 하드세그먼트와 소프트세그먼트의 강한 상분리 거동의 결과로 볼 수 있다. 그 결과 GAP-co-BO계 ETPE는 GAP계 ETPE보다 더 큰 파단강도와 더 낮은 파단신율 값을 나타냈다.

• 공업화학
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• 제10권1호
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• pp.35-40
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• 1999

Hard segment 함량이 35%와 53%로 서로 다른 두 개의 열가소성 폴리우레탄 시료 (각각 TPU-35와 TPU-35)와 이들을 70/30, 50/50, 30/70 wt%로 용융 블렌딩한 조성들이 annealing 온도와 시간에 따라 변화할 수 있는 유리전이온도와 용융피이크, 분자량 및 분자량 분포도의 변화를 관찰하였다. TPU의 $T_g$는 hard segment 함량이 많을수록 높은 값을 보였으며 annealing 온도와 시간에 따라 hard microdomain 구조의 미약한 관계에 의한 용융피이크의 크기와 온도 등이 변하였다. 이는 annealing에 의한 열이 long-range 혹은 short-range segmental motion의 거동, 비결정 microphase 구조의 order-disorder 전이, domain의 크기 및 결정구조의 질서도 등 여러 가지 복합적인 영향을 끼친 결과로 사료된다. 미세 결정의 용융 결과로 나타나는 $T_3$단일 피이크만이 존재하는 annealing 온도는 TPU-35, TPU-44와 TPU-53에 대해 각각 130, 170 및 $180^{\circ}C$이었다. Annealing 온도와 시간에 따른 분자량 및 분자량 분포도 변화 측정에서 TPU-35는 $135^{\circ}C$에서, TPU-44(TPU-35/TPU-53=50/50 블랜드)는 $170^{\circ}C$, 그리고 TPU-53은 $180^{\circ}C$에서 수평균 및 중량평균 분자량의 증가와 더불어 polydispersity(PI)는 감소를 보였다. 이 변화는 같은 조건의 annealing 온도에 따른 용융피이크 변화에서 $T_3$단일 피이크만 남게 되는 annealing온도와 일관성을 보이고 있는데, 이는 이들 시료가 특정한 annealing 온도에서 chain dissociation과 recombination이 동시에 일어나므로써 빚어진 결과로 추측된다.