신발겉창 재료용 열가소성 폴리우레탄 (TPU)/에틸렌-프로필렌-디엔 고무와 TPU/부타디엔 고무 블렌드

김지후 ( Ji Hoo Kim ),김규현 ( Gue Hyun Kim ) 한국고무학회 2013 엘라스토머 및 콤포지트 Vol.48 No.3

본 연구의 주요 목적은 신발 겉창 재료로 사용하기 위하여 열가소성 폴리우레탄 (TPU)의 내마모성과 습윤시의 내슬립성을 에틸렌-프로필렌-디엔 고무 (EPDM) 또는 폴리부타디엔 고무 (BR)를 블렌드하여 향상시키는 것이다. 10 wt%의 EPDM 또는 BR이 TPU에 투입되었을 때 TPU/EPDM과 TPU/BR 블렌드는 TPU보다 우수한 NBS 내마모도, 인장 물성 그리고 습윤 내슬립성을 보였다. 10 wt% 이상 투입될 때는 내마모도와 인장 물성 모두 감소하였다. 10 wt% 투입시의 내마모도와 인장물성 상승은 TPU의 상분리도 증가에 기인하는 것으로 보인다. The main objective of this study is to improve abrasion resistance and wet slip resistance of thermoplastic polyurethane (TPU) by blending with ethylene-propylene-diene monomer rubber (EPDM) or polybutadiene rubber (BR) for the application of the footwear outsole materials. With addition of 10 wt% of EPDM or BR, TPU/EPDM and TPU/BR blends exhibited higher NBS abrasion resistance, tensile properties and wet slip resistance than TPU. However, with further increasing content of EPDM and BR, abrasion resistance and tensile properties of the blends decreased. Improvement in abrasion resistance and tensile properties with 10 wt% of addition of EPDM or BR may be due to better microphase separation of TPU.

Effect of Hot Pressing/Melt Mixing on the Properties of Thermoplastic Polyurethane

이영희,강보경,유혜진,김정수,허재호,정영진,이동진,김한도 한국고분자학회 2009 Macromolecular Research Vol.17 No.8

In-depth understanding of the influence of hot pressing and melt processing on the properties of thermoplastic polyurethane (TPU) is critical for effective mechanical recycling of TPU scraps. Therefore, this study focused on the effects of hot pressing and melt mixing on molecular weight (MW), polydispersity index (PDI), melt index (MI), characteristic IR peaks, hardness, thermal degradation and mechanical properties of TPU. The original TPU pellet (o-TPU) showed two broad peaks at lower and higher MW regions. However, four TPU film samples, TPU-0 prepared only by hot pressing of o-TPU pellet and TPU-1, TPU-2 and TPU-3 obtained by hot pressing of melt mixed TPUs (where the numbers indicate the run number of melt mixing), exhibited only a single peak at higher MW region. The TPU-0 film sample had the highest Mn and the lowest PDI and hardness. The TPU-1 film sample had the highest Mw and tensile modulus. As the run number of melt mixing increased, the peak-intensity of hydrogen bonded C=O stretching increased, however, the free C=O peak intensity, tensile strength/elongation at break and average MW decreased. All the samples showed two stage degradations. The degradation temperatures of TPU-0 sample (359 oC and 394 ℃) were higher than those of o-TPU (342 ℃ and 391 ℃). While all the melt mixed samples degraded at almost the same temperature (365 ℃ and 381 ℃). The first round of hot pressing and melt mixing was found to be the critical condition which led to the significant changes of Mn/Mw/PDI, MI, mechanical property and thermal degradation of TPU.

Effect of Hot Pressing/Melt Mixing on the Properties of Thermoplastic Polyurethane

Lee, Young-Hee,Kang, Bo-Kyung,Kim, Han-Do,Yoo, Hye-Jin,Kim, Jung-Soo,Huh, Jae-Ho,Jung, Young-Jin,Lee, Dong-Jin The Polymer Society of Korea 2009 Macromolecular Research Vol.17 No.8

In-depth understanding of the influence of hot pressing and melt processing on the properties of thermoplastic polyurethane (TPU) is critical for effective mechanical recycling of TPU scraps. Therefore, this study focused on the effects of hot pressing and melt mixing on molecular weight (MW), polydispersity index (PDI), melt index (MI), characteristic IR peaks, hardness, thermal degradation and mechanical properties of TPU. The original TPU pellet (o-TPU) showed two broad peaks at lower and higher MW regions. However, four TPU film samples, TPU-0 prepared only by hot pressing of o-TPU pellet and TPU-1, TPU-2 and TPU-3 obtained by hot pressing of melt mixed TPUs (where the numbers indicate the run number of melt mixing), exhibited only a single peak at higher MW region. The TPU-0 film sample had the highest $M_n$ and the lowest PDI and hardness. The TPU-1 film sample had the highest $M_w$ and tensile modulus. As the run number of melt mixing increased, the peak-intensity of hydrogen bonded C=O stretching increased, however, the free C=O peak intensity, tensile strength/elongation at break and average MW decreased. All the samples showed two stage degradations. The degradation temperatures of TPU-0 sample (359 $^{\circ}C$ and 394 $^{\circ}C$)were higher than those of o-TPU (342 $^{\circ}C$ and 391 $^{\circ}C$). While all the melt mixed samples degraded at almost the same temperature (365 $^{\circ}C$ and 381 $^{\circ}C$). The first round of hot pressing and melt mixing was found to be the critical condition which led to the significant changes of $M_n$/$M_w$/PDI, MI, mechanical property and thermal degradation of TPU.

Edge TPU에서의 실시간성 보장을 위한 실시간 DNN 프레임워크

한창헌,오상은 한국차세대컴퓨팅학회 2022 한국차세대컴퓨팅학회 논문지 Vol.18 No.5

As deep neural networks (DNNs) have been recently deployed in many safety-critical real-time embedded systems, it has become essential to meet timing requirements that DNN inference tasks must complete their execution within given deadlines. To this end, most previous studies focus on utilizing GPU or CPU in edge computing environments to support real-time DNN tasks. Meanwhile, although Edge TPU is regarded as a next-generation AI processor for edge computing, there is a lack of studies on real-time guarantee for Edge TPU. Thus, this paper presents a novel real-time DNN framework that can satisfy the timing requirements of multiple DNN inference tasks in edge TPU environments. This framework provides 1) a cache memory allocation technique that considers the deadline of each task and 2) a scheduling technique based on model segmentation to reduce priority inversion phenomena. We evaluated the performance of our framework by using Google Coral dev board, an embedded board equipped with Edge TPU, and several image classification models. The experiment result shows that our framework can provide higher schedulability by 37% than the existing Edge TPU system. 최근 심층신경망 (DNN, deep neural network) 알고리즘이 많은 안전필수 실시간 시스템에 적용되기 시작하면서 DNN 추론 태스크의 실행이 주어진 마감 시간 안에 완료되어야 하는 타이밍 요구사항이 중요해졌다. 이를 위해 대부분의 선행 연구들은 DNN의 실시간성을 보장하기 위해 엣지 컴퓨팅 환경에서 GPU나 CPU와 같은 컴퓨팅 자원을 활용하는 것에 초점을 맞춘다. 이에 반면, Edge TPU는 엣지 컴퓨팅을 위한 차세대 인공지능 프로세서로 평가받고 있음에도 불구하고, Edge TPU를 위한 실시간성 보장 연구는 전무한 실정이다. 따라서 본 논문에서는 Edge TPU 환경에서 여러 DNN 추론 태스크들의 타이밍 요구사항을 만족시키는 새로운 실시간 DNN 프레임워크를 제안한다. 이 프레임워크에서는 1) 태스크 마감 시간을 고려하여 SRAM 캐시메모리를 할당하는 기법과 2) 우선순위 역전 현상을 줄이기 위한 모델 분할 기반의 스케줄링 기법을 제공한다. 본 연구에서는 Edge TPU가 장착된 Coral 개발 보드와 이미지 분류 모델들을 이용하여 해당 프레임워크의 성능을 검증하였다. 그 결과 기존 Edge TPU 기반 시스템보다 37%만큼 더 높은 스케줄링 가능성 (scheduablity)를 제공할 수 있음을 보였다.

열가소성 폴리우레탄 (TPU)/고무 블렌드의 마찰에 의한 표면 파괴 거동

전준하 ( Jun Ha Jeon ),박상민 ( Sang Min Park ),엄기용 ( Gi Yong Um ),배종우 ( Jong Woo Bea ) 한국접착및계면학회 2013 접착 및 계면 Vol.14 No.3

본 연구에서는 열가소성 폴리우레탄(TPU)과 EPDM, NBR 및 BR을 용융 블렌딩하여 TPU/Rubber 블렌드 필름을 제조하고 이들의 조성이 마찰시 표면 파괴와의 관계를 연구하였다. TPU/EPDM과 TPU/BR 블렌드의 마찰시 표면 파괴 특성이 개선되었으며 특히 BR이 우수하였다. 또한, TPU/BR 블렌드에서 BR의 함량이 10 wt% 이상 투입될 때 표면 파괴 및 마킹 특성이 개선되었다. Scanning electron microscopy (SEM) 분석으로부터 BR 함량이 증가할수록 연질상의 증가로 인한 표면 파괴 및 마킹 특성의 개선으로 추정할 수 있었다. In this work, the thermoplastic polyurethane (TPU) was melt-blended with EPDM, NBR and BR to form TPU/Rubber blend films, their composition and friction-induced surface fracture relationship was investigated. TPU/EPDM and TPU/BR blends exhibited the improved friction-induced surface fracture, especially the effect of BR was excellent. With addition of more than 10 wt% BR, TPU/BR blends exhibited the improved friction-induced surface fracture. The increase of the soft segment with increasing BR content, which was confirmed by scanning electron microscopy (SEM) analysis enabled us to estimate the improved friction-induced surface fracture.

A highly stretchable large strain sensor based on PEDOT–thermoplastic polyurethane hybrid prepared via in situ vapor phase polymerization

Losaria, Pauline May,Yim, Jin-Heong THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2019 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.74 No.-

<P><B>Abstract</B></P> <P>Strain sensors based on percolated networks of poly(3,4-ethylenedioxythiophene) (PEDOT) in thermoplastic polyurethane (TPU) matrix fabricated through in situ vapor phase polymerization (VPP) is reported. The hybrid made of elastomer and conductive polymer shows uniform PEDOT distribution on the surface and inner side of the TPU due to the effective penetration, diffusion, and polymerization of EDOT. Performance of sensors using two kinds of oxidants (FeCl<SUB>3</SUB> or iron(III) <I>p</I>-toluenesulfonate(FTS)) are compared and the concentration is varied to obtain the best electromechanical properties. Amount of PEDOT increases with increasing amount of oxidant: thereby improving the electrical conductivity, while the elasticity of the hybrid decreases. The elasticity reduction phenomenon is diminished when FTS is used due to the plasticizer effect of the tosylate ion on the TPU. The performances of PEDOT–TPU hybrids prepared with FTS are excellent in the terms of stretchability (>300%), gauge factor (GF > 10 @ strain 100%), resistance variation reproducibility under various strain modes, small hysteresis, and durability (>1000 cycle). With the electromechanical performance, as well as cheap and scalable production, the PEDOT/TPU sensor holds tremendous prospects on flexible and stretchable devices for human motion monitoring, as well as present strategies on architecture of conductive soft materials.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The use of FTS (iron(III) <I>p</I>-toluenesulfonate) has a plasticizing effect on PEDOT–TPU strain sensor. </LI> <LI> Uniform PEDOT particle distribution inside the TPU elastomer is achieved by VPP. </LI> <LI> The sensors combine cheap and scalable production with high stretchability and attractive properties. </LI> <LI> Effect of oxidant type and concentration on electromechanical properties is investigated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>A highly stretchable strain sensor (> 300%) is fabricated by VPP-assisted hybridization between PEDOT and a thermoplastic polyurethane (TPU). Sulfur from PEDOT particles is uniformly distributed on the surface and inside the cross-section of the substrate. It would be speculated that the tosylate anion generated from FTS act as a plasticizer for the TPU matrix as well as a dopant of PEDOT.</P> <P>[DISPLAY OMISSION]</P>

A Comparative Study of the Thermoplastic Polyurethane/Carbon Nanotube and Natural Rubber/Carbon Nanotube Composites According to Their Mechanical and Electrical Properties

Lyhuong Tran,김주용 한국섬유공학회 2018 Fibers and polymers Vol.19 No.9

The present study investigated Thermoplastic Polyurethane (TPU), Natural rubber (NR) and their composites in terms of their mechanical and electrical properties for developing wearable stretch sensors. Both TPU and NR were added 2 %wt Multi-wall Carbon Nanotube (MWCNT), then in order to test their influences on TPU/CNT and NR/CNT composites. The result showed that Young’s modulus and Yield point of this experiment were higher than bare TPU and NR, whereas their stress-strain hysteresis loops were bigger than bare TPU and NR. Moreover, the Gauge factor (GF) value of TPU/CNT was much higher than NR/CNT composites at 100 % strain with 7.08. TPU/CNT composites promise to have many applications in the field of stretch sensors with good stability and durability while NR and NR/CNT were easy deformed when the stretch was applied.

3D프린팅을 이용한 편성물의 역학적 특성 연구 -PLA, TPU 필라멘트를 중심으로-

한유정 ( Yoojung Han ),김종준 ( Jongjun Kim ) 한국패션비즈니스학회 2018 패션 비즈니스 Vol.22 No.4

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.

FDM 3D 프린팅을 이용한 힌지 접힘 구조체의 압축 특성에 관한 연구

박예은,이선희 한국섬유공학회 2023 한국섬유공학회지 Vol.60 No.4

In this study, a unit hinge structure (UHG) and a multi hinge pattern (MHG) were developed using two different hardnesses of thermoplastic polyurethane (TPU) filaments and their compression behaviors were compared. It was analyzed that the modeling method, actual printing time and weight, and tensile and compression properties according to two different hardnesses of TPU filaments. As a result, three types of UHG in the form of a rectangular parallelepiped with constant hinge and frame thickness and height were developed, and based on this, three types of MHG were developed by tessellation. In the tensile properties, it was confirmed that TPU95A is a stiffer and more rigid material than TPU87A. In the case of UHG compression properties, the sample made of TPU87A did not show shear deformation, but the sample made of TPU95A showed the maximum strain at the 50% point regardless of the type. In the case of MHG compression properties, it was confirmed that the size and pressure of UHG are inversely proportional regardless of the filament, and the shear deformation appears well as the size increases. In the case of TPU95A, stronger pressure was required, which can be appropriately adjusted according to the user's experience.

압출 구형 TPU Powder 적용 파우더 슬러쉬 공법 개발

곽성복(Sungbok Kwak),주상률(Sangyul Ju),이상락(Sangrak Lee),문찬성(Chansung Moon),정기연(Giyun Jeoung),한인수(Insu Han),조성민(Sungmin Cho) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4

크래쉬 패드 분체성형 공법적용 TPU 구형 파우더 소재 개발은 세계 최초로 Micro-pelletizing 기술을 분체 성형에 도입하여 기존3단계로 제조되는 파우더 제조공정을 1단계로의 공정단축을 통한 제조비용 감소가 가능하고, 특히 고비용의 저온동결 분쇄 공정을 생략됨으로써 제조비용을 획기적으로 줄일 수 있다. 또한, 입도분포 균열화를 통한 재료 Loss율 저감, 입자 구상화로 인한 분체 흐름성 향상을 통하여 핀홀(Pin-Hole)발생 억제 등의 우수한 성형성 확보가 가능하며 저온특성이 우수하여 Invisible 에어백장착이 가능하여 고부가가치화가 가능하다. 재활용성 측면에서 보면 TPU는 PVC와는 달리 열 회수를 위한 소각 시 인체유해 성분을 배출하지 않으므로 재활용성 향상이 가능하며, TPU의 경우는 중간재인 PU Foam과의 일체화로 재활용성이 더욱 향상된다. 따라서 크래쉬 패드 분체성형 공법적용 TPU 구형 파우더 소재 개발은 제조공정 단축을 통한 제조 비용감소, 소비자들의 내구성 향상 요구 만족 그리고 재활용성을 향상시킬 수 있는 기술로서 최근에 국내 자동차 제조사가 직면한 생존경쟁에서 유리한 위치를 점 할 수 있는 획기적 기술로서 연구의 가치가 높다고 판단된다. 본 연구에서는 이러한 TPU 소재를 최적의 입자 사이즈와 분체성형공법(PSM)에 적합한 소재를 개발하고자 한다.