Effect of soft/hard segments in poly (tetramethylene glycol)-Polyurethane for water barrier film

Kang, Kyung Seok,Jee, Chanhyuk,Bae, Ji-Hong,Jung, Hyo Jin,Kim, Byeong Joo,Huh, PilHo Elsevier 2018 Progress in organic coatings Vol.123 No.-

<P><B>Abstract</B></P> <P>A series of thermoplastic polyurethanes (TPUs) with the same molecular weight but different soft/hard ratios were synthesized by in-situ condensation polymerization using poly (tetramethylene glycol) (PTMG) as the polyol and methylene diphenyl diisocyanate (MDI) as the isocyanate. The weight fractions of the hard segments were varied from 0.0 to 0.4. The structures of the TPU series were analyzed by Fourier transform infrared spectroscopy and gel permeation chromatography. The changes in the thermal and optical properties due to the hard segment crystallinity were also measured by differential scanning calorimetry and UV–vis spectroscopy. Increasing the hard content promoted phase separation and served as absorption blocks in the TPU. The water vapor permeability of the TPU films with different soft/hard ratios ranged from 223.63 to 116.26 g/m<SUP>2</SUP> day.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Synthesis of thermoplastic polyurethanes with the similar molecular weight but different soft/hard segment ratios. </LI> <LI> Different soft/hard segment ratio used as a key to control the phase separation and absorption blocks of thermoplastic polyurethanes. </LI> <LI> Effects of soft/hard ratios on the water-vapor barrier property, which leads to the reinforcing encapsulation performance of thermoplastic polyurethane. </LI> </UL> </P>

Plasticizer 적용에 따른 thermoplastic polyurethane의 열적, 기계적 특성연구

전호균,박현주,오상택 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

Thermoplastic polyurethane(TPU)은 고무와 유사한 탄성을 가지고, 유연성, 기계적 물성 및 내구성, 내마모성이 우수한 소재로 산업 전분야에 걸쳐 널리 사용되고 있다. 일반적으로 TPU는 isocyanate와 polyol, chain extender 등의 3성분의 조합에 의해서 구성되며, 사출, 압출, calendar, blow 성형 등 가공방법에 따라 다양한 용도로 적용된다. 본 연구에서는 핫멜트 접착제용으로서 thermoplastic polyurethane을 합성 후, plasticizer적용을 통한 열적, 기계적 특성을 연구하였다. 핫멜트 접착제는 열에 의해 용융시켜 적용하는 접착제로, 휘발성 유기용제의 배출이 적어 친환경 접착제로서 사용이 증가되고 있으며, 최근에는 지구온난화를 방지하기 위한 노력의 일환으로 환경보호의 관점에서도 제도화 되고 있다. 일반적으로 핫멜트 접착제는 실온에서 고체물질이지만 열을 가하면 액체 상태로 용융되어 피착재에 대해 접착력을 갖게 되고, 용융된 상태의 핫멜트 접착제를 냉각시키면 고체형태로 회복되어 응집력을 회복한다. 접착력은 표면의 구멍이나 요철에 의해 액상의 접착제가 흘러 들어가 접착력을 높이는 투묘 효과(anchoring effect)에 영향을 받는데, 이 효과를 잘 이용하기 위해서 핫멜트 접착제는 용융되었을 때, 충분한 흐름성을 확보해야 한다. 종래의 범용 핫멜트 접착제는 주로 EVA를 주성분으로 하고, 접착력 향상을 위한 증점착제 및 점도개선 목적으로 왁스를 첨가하여 제조 된다. 그러나 EVA와 왁스의 상용성이 좋지 않으면 점도를 효과적으로 낮추지 못할 뿐더러, 상분리가 일어나 접착력이 현저히 감소하게 된다. 본 연구에서는 EVA 대비 접착특성이 우수한 thermoplastic polyurethane을 적용하고, plasticizer를 적용하여 종래의 접착력을 유지하면서도 상대적으로 낮은 온도에서도 취급이 용이한 핫멜트 접착제 조성물의 특성을 연구하였으며, 아울러 이들의 열적, 기계적 특성을 확인하였다.

1P-49 Surface hydrophobicity and thermal stability of dynamically vulcanized thermoplastic polyurethane/silicone rubber blends

김수빈,장영욱 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

Dynamically vulcanized thermoplastic polyurethane(TPU)/silicone rubber(Q) blends were prepared in internal mixer using dicumyl peroxide as a curative and two-different type of coagents. Effects of silicone rubber content and dynamic vulcanization on surface morphology, wettability, and mechanical properties of the blends were characterized by water contact angle measurement, atomic force microscopy(AFM), and tensile test. Thermo-oxidative stability of the blend was examined using TGA, and the kinetic analysis was performed by using Kissinger method to obtain apparent activation energy and related parameters for the thermo-oxidative degradation.

Photopolymerization of Thermoplastic Polyurethane/Acrylate Blends

최영선,박시영,김원호,박대원 한국화학공학회 2005 Korean Journal of Chemical Engineering Vol.22 No.5

The kinetics of photopolymerization of thermoplastic polyurethane/acrylate blends have been studied usingin nature at the initial stage of reaction; then a retardation of the reaction conversion occurred gradually as the polymermatrix became vitrified and the reaction became difusion controlled. A kinetic rate equation with a difusion controlfactor term has been employed to characterize the difusion-controlled reaction behavior. As the reaction conversionreaches the transition point, at which the maximum value of kp/kt0.5 in the rate expresion is obtained, the reaction be-comes to be controlled by difusion due to the restricted mobility of acrylate macromonomers, resulting in the rapiddrop of the polymerization rate even keeping the same reactivity of all the double bonds of acrylate macromonomers.TPU content in the formulations. As the content of thermoplastic polyurethane increased, the polymerization rate in-creased in the early stage of cure reaction. Blends containing polyurethane up to 30 phr have single glass transitiontemperature, which indicates that they are miscible in blends and no phase separation has been observed.

Morphological and physical properties of a thermoplastic polyurethane reinforced with functionalized graphene sheet

Nguyen, Duc Anh,Lee, Yu Rok,Raghu, Anjanapura V,Jeong, Han Mo,Shin, Cheol Min,Kim, Byung Kyu John Wiley Sons, Ltd. 2009 Polymer international Vol.58 No.4

<P>BACKGROUND: Functionalized graphene sheet (FGS) was recently introduced as a new nano-sized conductive filler, but little work has yet examined the possibility of using FGS as a nanofiller in the preparation of polymer nanocomposites. In particular, there are currently no published papers that evaluate polyurethane/FGS nanocomposites. The purpose of this study was to prepare a polyurethane/FGS nanocomposite and examine the morphological and physical properties of the material.</P><P>RESULTS: A cast nanocomposite film was prepared from a mixture of thermoplastic polyurethane (TPU) solution and FGS suspended in methyl ethyl ketone. The FGS dispersed on the nanoscale throughout the TPU matrix and effectively enhanced the conductivity. A nanocomposite containing 2 parts of FGS per 100 parts of TPU had an electrical conductivity of 10<SUP>−4</SUP> S cm<SUP>−1</SUP>, a 10<SUP>7</SUP> times increase over that of pristine TPU. The dynamic mechanical properties showed that the FGS efficiently reinforced the TPU matrix, particularly in the temperature region above the soft segment melt.</P><P>CONCLUSION: Our results show that FGS has a high affinity for TPU, and it could therefore be used effectively in the preparation of TPU/FGS nanocomposites without any further chemical surface treatment. This indicates that FGS is an effective and convenient new material that could be used for the modification of polyurethane. It could also be used in place of other nano-sized conductive fillers, such as carbon nanotubes. Copyright © 2009 Society of Chemical Industry</P>

사출성형 열가소성 폴리우레탄의 물리적 성질에 미치는 금형 온도 영향

김성근 ( Seong Geun Kim ),구엔빈칸 ( Vinh Khanh Nguyen ),이명걸 ( Ming Ji Lee ),방수진 ( Su Jin Pang ),이대수 ( Dai Soo Lee ) 한국고무학회 2004 엘라스토머 및 콤포지트 Vol.39 No.4

경도를 달리하는 에스테르계 및 에테르계 열가소성 폴리우레탄(thermoplastic polyurethane: TPU)의 사출에서 금형 온도가 물리적 성질에 미치는 영향을 조사하였다 TPU의 연질부 유리전이온도는 금형 온도 변화에 따라 거의 변화하지 않았으며, 연질부와 경질부의 상분리는 금형온도의 영향을 별로 받지 않는 것으로 판단되었다. 그러나 에스테르계와 에테르계 TPU는 종류에 관계없이 공통적으로 경도가 높은 TPU들은 금형온도를 높이는 경우 결정성, 고무상 평탄 온도영역, 인장강도가 감소하였으나, 경도가 낯은 TPU들은 오히려 결정성, 고무상 평탄 온도영역, 인장강도의 증가를 보였다. TPU의 사출 성형 금형 온도에 따른 물리적 성질의 차이를 결정성경질부의 결정화와 물리적 가교효과 차이로 해석하였다. Ester- and ether-based thermoplastic polyurethanes of different hardness were injection molded at different mold temperatures and effects of mold temperature on the physical properties of TPUs were investigated. Glass transition temperatures of soft segments of TPUs were hardly changed by mold temperatures. The phase separation of soft and hard segments of injection molded TPUs were affected little by mold temperatures. However, crystallinity of hard segments, temperature range of rubbery plateau, and tensile strength of injection molded TPUs decreased with increasing mold temperatures for TPUs of high hardness. However, injection molded TPUs of low hardness showed increases of crystallinity of hard segments, temperature range of rubbery plateau, and tensile strength with increasing mold temperatures. Different physical properties of injection molded TPUs depending on mold temperatures were attributed to different crystallization and physical crosslinking effects of hard segments.

Mechanical, Tensile Creep and Viscoelastic Properties of Thermoplastic Polyurethane/Polycarbonate Blends

Alper Kasgoz 한국섬유공학회 2021 Fibers and polymers Vol.22 No.2

This study investigated the morphological, mechanical and solid-state creep properties of thermoplasticpolyurethane/polycarbonate blends. Blend film samples were prepared via the solution-mixing method. The morphologicaland mechanical properties of the samples were investigated by scanning electron microscope (SEM) and universal testmachine. Solid-state creep tests were also performed by dynamic mechanic analyzer (DMA) under a stress value of 3 MPa atdifferent temperatures (30, 40, and 50 °C). Morphological observations indicated that the blend samples had a compatiblestructure due to the polar nature of PC and TPU. In the mechanical tests, it was found that the tensile modulus value improvedsignificantly by incorporation of PC, whereas the strain at break and toughness values reduced. Accordingly, the blendsample that contained PC at the rate of 10 % (wt.) showed a higher tensile modulus and lower toughness than neat TPU by2.85 and 0.56 times, respectively. In the creep strain analyses, the viscoelastic structure and long-term creep performance ofthe samples were analyzed by the Burger model, time-temperature superposition (TTS) approach and Findley model. Theexperimental values and the model predictions indicated that incorporation of PC into the TPU phase improved the creepresistance of TPU significantly. For example, the creep strain value of neat TPU could be reduced by 68 % and 98 % in therespective cases of the PC concentrations of 10 % (wt.) and 50 % (wt.). Finally, the experimental creep-recovery behavior ofthe samples was investigated, and the permanent strain values were determined by the Weibull Distribution Function (WDF).

Morphology and Mechanical Properties of Thermoplastic Polyurethane/Colemanite Composites

Ferhat ?en,Seyfullah Madakba?,Emre Ba?turk,Memet Vezir Kahraman 한국고분자학회 2017 폴리머 Vol.41 No.6

The aim of this study was to improve thermal stability, mechanical and surface properties of thermoplastic polyurethane (TPU) with the addition of colemanite. The TPU/colemanite composites having various ratios of TPU and colemanite were prepared. The chemical structure of the prepared composites was investigated by Fourier transform infrared spectroscopy (FTIR). Thermal properties of the samples were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Mechanical properties of the samples were characterized with stress-strain test. Hydrophobicity of the samples was determined by the contact angle measurements. Moreover, the surface morphology of the samples was investigated by a scanning electron microscopy - energy dispersive spectrometer mapping (SEMEDS). Finally, the obtained results prove that the prepared composites have good thermal, mechanical and surface properties and that they can be used in many applications such as the electronic devices, materials engineering and other emergent.

Controlling properties of thermoplastic polyurethane-based foam through adopting different type of oligomers

박상현,이경진 한국고분자학회 2024 Macromolecular Research Vol.32 No.3

Thermoplastic polyurethane (TPU) has been widely utilized in varied fields due to their excellent properties such as flexibility, stretchability, thermal stability, resilience, etc. However, it is relatively difficult to control their properties comparing to PU because most of TPU properties are decided in synthetic level. Herein, aromatic polyols were introduced into desired TPU in synthetic level to overcome the issue and improve mechanical properties of TPU. Furthermore, the optimization condition is suggested by controlling the molar ratio of aliphatic/aromatic polyols. Finally, porous TPU sheets were fabricated via VIPS method using synthesized TPU. Tensile and compression testing were executed to compare the mechanical properties of each TPU and porous TPU sheet according to the molar ratio of aliphatic/aromatic polyols.

Materials (Organic, Inorganic, Electronic, Thin Films), Polymer, Fluidization, Particle Technology : Photopolymerization of Thermoplastic Polyurethane/Acrylate Blends

( Young Son Choe ),( Si Young Park ),( Won Ho Kim ),( Dae Won Park ) 한국화학공학회 2005 Korean Journal of Chemical Engineering Vol.22 No.5