수정진동자의 폴리우레탄 합성반응 해석에 응용

조홍식,한대상,박진영,김종민,박지선,김광,장상목 동아대학교 생산기술연구소 1999 生産技術硏究所硏究論文集 Vol.4 No.2

In this study, we investigated the reaction characteristics of polyurethane synthesis by measuring simultaneously resonant frequency and resonant resistance with a quartz crystal analyzer. Polyurethane synthesis gives the rapid decrease of resonant frequency by automatic catalyst effect due to the production of polyurethane at the initial stage. In prepolymer(PP) synthesis, the resonant frequency is slowly stabilized after the rapid decrease at any point of time. But in segmented polyurethane synthesis that chain-extender was added, the resonant frequency increased again after the rapid decrease at any point of time. It is believed that this tendency takes place because the chain-extender, 1,4-butandiol, changes soft segment into hard segment. As the result, we suggest that the reaction characteristics of polyurethane synthesis can be analyzed in on-line using a quartz crystal analyzer, and the systhesis mechanism can also be interpreted.

Thermal Sensitive Polyurethane Membranes with Desirable Switch Temperatures

Hu Zhou,Jianxian Zeng,Haojun Fan,Yuansen Liu,Jian Zhou 한국고분자학회 2010 Macromolecular Research Vol.18 No.11

Chemical synthesis and physical blending methods were used to prepare thermal sensitive polyurethanes (TSPU) with single or double thermal switches. In the design of the formula, polycaprolactone diol (PCL) with a molecular weight 10,000 and 4,000 and polytetramethylene glycol (PTMG) with a molecular weight 3,000 and 2,000 were used as the soft segments. The effects of the crystallinity and compatibility of the soft segments on the phase transition temperatures of the soft segments of TSPU (defined as switch temperature, Ts) were investigated in detail. To examine the thermal sensitivity of the thermal switch, water vapor permeability (WVP) experiments were performed to investigate the mass transport as a function of temperature. Differential scanning calorimetry (DSC)indicated that all the original TSPUs had a phase separated structure that was independent of the phase transition temperature of the soft and hard segments. The Ts values are determined mostly by the melting temperatures of the soft segments. On the other hand, for their blends, the Ts values are determined by the compatibility of the soft segments and the blending weight ratio. The blends of the PCL-based TSPUs showed good compatibility and single Ts due to the similar structure of the soft segments (just a difference in molecular weight), whereas for the PCL-based and PTMG-based TSPUs (the molecular structure is very different) blends, the Ts two independent values and blending weight ratio-dependent features due to the difference in the structure of the soft segments. Water vapor permeability analysis revealed the mass transport showed switching features to thermal stimuli, i.e. when the temperature reached the Ts, the WVPs of membranes showed rapid changes. On the other hand, the sensitivity of the thermal switch characterized by WVP improvement showed a dependence on the degree of crystallinity of the soft segments,i.e. well-organized soft segment structure is beneficial for improving the thermal sensitivity. Overall, TSPU membranes with a single Ts and different thermal sensitivity can be prepared using different crystalline poly-diols as the soft segments and blending two types of TSPUs with similar soft segments in the molecule structure, whereas TSPU with a double Ts can be achieved easily by blending two types of TSPUs with different soft segments.

Effect of Polymerization Procedure on Thermal and Mechanical Properties of Polyether Based Thermoplastic Polyurethanes

Kim, Seong-Geun,Lee, Dai-Soo The Polymer Society of Korea 2002 Macromolecular Research Vol.10 No.6

Thermoplastic polyurethanes (TPUs) with different hard segment length has been prepared from a fixed molar ratio of poly(tetramethylene ether glycol), 4,4'-diphenylmethane diisocyanate, and 1,4-butanediol by different polymerization procedures. Results reveal that the on-set temperature of endotherms ( $T_{cc}$ ) due to the crystallization of hard segments by cooling the TPUs from melt and the peak temperature of endotherms due to the melting of hard segments ( $T_{mh}$ ) by heating the TPUs increased and levelled off with increasing the hard segment length of TPUs. It has also been observed that soft segment glass transition temperature ( $T_{gs}$ ) of TPU decreased slightly with increasing the hard segment length, which explains less mixing of soft segments and hard segments. In tensile measurement of TPUs, strain hardening is observed with increasing the hard segment length, which is attributed to the strain induced crystallization of soft segments.

Color Depth Enhancement and Improved Rubbing Color Fastness of Cotton Knitted Fabrics via Polyurethane with PCL/PCDL Polyester Soft Segment

Yan Xie,Shaofeng Lu,Wenzhao Shi,Haizhu Wang,Kuang Wang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.9

Water-based polyurethane (WPU) provides a number of benefits over typical solvent-based polyurethane. WPU ismore environmentally friendly, safe, and reliable. The WPU with polycaprolactone diol/polycarbonate diol (PCL/PCDL)complex soft segment was developed using a prepolymer technique to enhance the color depth of cotton knitted fabrics dyedwith reactive dyes. The appearance, particle size, zeta potential, and viscosity of WPU emulsions were analyzed. Thechemical structure, thermal stability, phase change performance, and topography of WPU films were characterized byFourier-transform infrared (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and atomicforce microscopy (AFM), respectively. The tensile and hydrophilic properties of the WPU films were examined by anelectronic universal testing machine and contact angle goniometer, respectively. The K/S value, rubbing fastness, washingfastness, and wearability of finished and unfinished dark cotton knitted fabrics were measured. Simultaneously, the chemicalstructure and morphology of fabrics were investigated using FTIR and scanning electron microscopy (SEM). The resultsshow the WPU-2 emulsion demonstrated excellent stability, and the WPU-2 film showed superior thermal stability. The K/Svalue of the dark cotton knitted fabric finished with WPU-2 emulsion (40 g/l) increased by 18.58 %, and the wet rubbingcolor fastness of the resulting fabric was enhanced. The SEM results show a layer of film covered the surface of the finishedfabric. In summary, the WPU can provide a new technique for enhancing the color depth of fabrics.

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>

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.

soft segment의 함량에 따른 폴리우레탄의 물리적 특성 변화

오현진,박희웅,신승한 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1

Temporary Protective Coating은 다양한 제품의 제조공정, Shipping공정 등에서 널리 이용되고 있다. 이러한 코팅기술은 단지 제거 / 재코팅하는 것 만으로도 편리하게 scratching, nicking, pitting, staining, corrosion 등으로부터 표면 손상을 막아주며 외부로의 오염을 막아 세척도 쉽게 할 수 있다. 이 코팅기술은 다양한 분산성 용액을 이용하여 접근되고 있다. 그 중 수분산성 폴리우레탄 용액을 이용한 응용이 쉽고 다양한 어플리케이션에 적용할 수 있으며, 유기 용매를 사용할 필요가 없어 친환경적이라는 장점이 있다. 본 연구에서는 이러한 Temporary Protective Coating에 응용가능한, 다양한 조성의 수분산성 폴리우레탄을 제조하고 물리적 특성을 Dynamic mechanical analysis(DMA), Differential scanning calorimetry(DSC)와 Thermal gravimetric analysis(TGA)의 분석을 통하여 그 가능성을 타진해보았다.

Effect of NCO/OH equivalent ratio on the properties of polyurethane dispersion

김진명,권용록,김은진,김정수,김동현 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

Water-based polyurethane dispersion (PUD) is being researched to reduce the amount of volatile organic compound emissions and environmental issues, and to improve the working environment. The physical properties of polyurethane were changed according to the ratio of the hard segments and the soft segments, and the molecular weight. The molecular weight and mechanical properties of polyurethane prepared by adjusting the NCO/OH equivalent ratio were compared with each other. The structure of synthesized polyurethane was confirmed by FT-IR analysis. Reactivity of polyol and isophorone diisocyanate with chain extender of dimethylol propionic acid were confirmed by dibutylamine inverse titration. The molecular weights of polyurethane was measured using GPC. The Mechanical properties of polyurethane was obtained using universal testing machine.

Synthesis and properties of the GAP-co-PBO based energetic thermoplastic polyurethane

설양호,권정옥,노시태,강신춘,권순길 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0

We perform a comparative study to investigate the properties of the energetic thermoplastic polyurethane (ETPU). A series of glycidyl azide polymer (GAP) / random copolymer of GAP and butylene oxide (GAPco-BO) based energetic thermoplastic polyurethane (GAP/GAP-co-BOESPU) with different hard segment content, which is from 25% to 50%,was synthesized by solution polymerization in tetrahydrofuran (THF) and their properties were investigated. The ETPUs were characterized with Fourier transform infrared-attenuated total reflection spectroscopy (ATR FT-IR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and universal testing machine (UTM).

The effect of hard segment content on the properties of the Glycidyl Azaid Polyol based polyurethane foam

김태성,강신춘,권정옥,노시태,권순길 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0

최근 신기술 재료로서 발포체에 대한 개발이 에너지 절감 소재 분야, 극저온 단열 소제분야등에의 응용을 목적으로 새롭게 연구하고 있다. 이와 같이 발포체는 과거에는 전통적 소재 개발을 목표로 한 연구들이 이루어 졌으며, 최근에는 특수 분야에의 응용을 목적으로 신발포체 소재 개발에 대한 산업적 학문적 연구개발이 이루어지고 있다. 무기체계분야에서도 발포체의 다양성의 장점과 발포구조를 포함하여 연소속도의 제어 및 높은 연소속도의 장점을 이용한 발포추진제가 개발되었다.본 연구에서는 물리적 발포제인 Cyclopentane를 이용하여 아자이드기 함유 글리 시딜아자이드(Glycidyl Azaid Polmer)계 폴리우레탄 발포체를 합성하였으며,발포체의 하드세그먼트의 함량에 따라 폴리우레탄 발포체의 발포거동 변화와 이에 따른 열적 성질, 발포체의 모폴로지 및 셀의 크기 변화에 미치는 영향을 각각 Foam qualification system, 시차주사열량계(DSC), 주사전자 현미경(SEM)등을 이용하여 고찰하였다.