• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2002년도 봄 학술발표회 논문집
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• pp.466-469
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• 2002

Polyurethane(PU)은 segmented 블록공중합체로써 상온보다 높은 유리전이온도(glass transition temperature, Tg)를 갖는 hard segment(H.S)와 상온보다 낮은 Tg를 갖는 soft segment (S.S)로 구성되어 있다. 이들 두 segment간의 열역학적 불친화성으로 인해 미세 상분리 구조를 갖는다$^1$. 그 결과 hard segment-rich hard domain과 soft segment-rich soft matrix의 구조를 이룬다. 이중 hard domain(HD)은 상온에서 glassy한 성격을 띄므로 물리적 가교점과 충진제의 역할을 하며 soft domain(SD)은 rubbery한 성질을 가지므로 polurethane에 탄성을 부여하는 역할을 한다. (중략)

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 가을 학술발표회 논문집
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• pp.195-196
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• 2003

Polyurethane(PU)은 물리적 화학적 성질이 매우 다른 두 segment(hard/soft)로 이루어진 block copolymer로서 상온에서 미세상분리된 구조를 가진다. 이런 미세 상분리 구조는 PU의 물리적 성질을 결정하는 가장 중요한 요소이며, hard segment(H/S)의 화학적 구조에 따른 PU사슬의 강직성은 H/S의 packing및 상분리도에 큰 영향을 미친다. 본 연구에서는 H/S의 화학적 구조를 변화시켜 사슬의 강직성이 서로 다른 다양한 PU을 합성하였으며 Synchrotron SAXS와 FTIR-dichioism을 이용하여 PU 사슬의 강직성에 따른 거시적인 domain의 변형거동과 미시적인 사슬의 변형거동을 관찰 하였다. (중략)

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1998년도 봄 학술발표회 논문집
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• pp.5-8
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• 1998

Polyurethane elastomers are segmented cocoplymer with an [HS]n-type structure. Typically, these materials are two-phase systems, prepared from relatively polar and stiff component called the hard segment(H) and relatively flexible component known as the soft segment(S). Diisocyanate and chain extender together form the hard segment, which is dispersed within a matrix of the soft segment, composed of the macrodiolos.(omitted)

• 한국안광학회지
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• 제6권1호
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• pp.119-124
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• 2001

디메틸 테레프탈레이트 (DMT), 1.4-부탄디올 (1.4-BD) 그리고 분자량이 2000인 폴리테트라 메틸렌 에테르 글리콜 (PTMG)로 부터 폴리에스터계 열가소성 탄성체 (TPEE)를 합성할 수 있었다. 열적 안정성 및 기계적 물성을 증대시킬 목적으로 열처리를 하였으며, 이에 따라 결정성 hard segmen의 보다 규칙적인 배열로 인한 향상된 물성을 확인 할 수 있었다. 본 실험에서 합성된 공중합체는 soft segment의 함량이 증가함에 따라 융점 및 결정화도가 감소함을 보여 주었다. 기계적 물성의 경우, soft segment의 함량이 35%인 공중합체가 soft segment와 hard segment간 최적의 물리적 가교점 형성으로 인하여 가장 우수함이 관찰되었다.

• 폴리머
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• 제24권2호
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• pp.149-158
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• 2000

흡유성이 우수한 발포 폴리우레탄(EPU)을 제조하기 위하여 soft segment로는 친유성 polyol인 polypropyleneglycol (PPG)를 사용하고 hard segment로는 toluenediisocyanate (TDI)와 $H_2O$를 사용하였다. Soft segment 함량이 흡유성과 발포체의 기계적 특성에 미치는 영향을 조사하기 위하여 PPG 평균 분자량((equation omitted) 1000, 2000, 3000)에 따라 one-shot법으로 EPU를 제조한 결과 PPG 평균분자량이 3000에서 1000으로 감소할수록 흡유량과 인장강도는 각각 1460%에서 3010%, 0.26 $kg_{f}$ /$cm^2$에서 0.55 $kg_{f}$ /$cm^2$로 동시에 증가하였다. Hard segment 함량비인 (isocyanate index, r=[NCO]/[OH] r이 1.0에서 1.2로 증가할수록 allophanate와 biuret 결합 형성에 기인하여 EPU의 인장강도가 0.56$kg_{f}$ /$cm^2$에서 0.95 $kg_{f}$ /$cm^2$로 증가하였으나, surfactant (S-A)의 함량은 1.0 pbw에서 2.5 pbw로 증가할수록 closed cell 구조의 형성으로 인하여 흡유량이 3634%에서 3312%로 감소됨을 알 수 있었다.

• Elastomers and Composites
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• 제54권4호
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• pp.271-278
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• 2019

Polyurethane elastomers (PUEs) were synthesized using trans-1,4-bis(isocyanatomethyl) cyclohexane (1,4-H₆XDI), poly(oxytetramethylene) glycol, 1,4-butanediol (BD), and 1,1,1-trimethylol propane (TMP). To control the molecular aggregation state and mechanical properties of these PUEs, hard segment contents of 20 and 30 wt% and BD/TMP ratios of 10/0 and 8/2 were chosen. Differential scanning calorimetry and small-angle X-ray scattering measurements revealed that the degree of microphase separation increased with an increase in both hard segment content and BD ratio. The Young's modulus and strain at break of the 1,4-H₆XDI-based PUE were 6-20 MPa and 5-15, respectively. Incorporation of 20% TMP as a cross-linking agent into BD increased the melting temperature of the hard segment chains, that is, heat resistance, and decreased the Young's modulus. This could be due to the low density of the physical cross-linking network and the dispersion of hard segment chains in the soft segment matrix in the PUE in the presence of 20% TMP.

• 폴리머
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• 제36권4호
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• pp.513-518
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• 2012

열적으로 안정한 탄화수소계 액상 파라핀인 YK-D130을 분산매로 사용하여 ${\omega}$-amino carboxylic acid와 adipic aicd로부터 폴리아미드 12(PA12) 올리고머(oPA1)를 제조하였으며 이들을 통상의 벌크중합으로 제조되는 비슷한 분자량의 폴리아미드 올리고머(oPA2)로 합성하여 분자량과 기타 특성을 비교하였다. 색도 분석 결과 oPA1이 더 밝은 백색을 나타냈고, GPC 결과로부터 oPA1가 더 좁은 분자량 분포를 보였다. 나아가 oPA1과 oPA2를 hard segment로 하고 poly(tetramethylene glycol)(PTMG)을 soft segment로 하는 탄성의 poly(ether-block-amide)(PEBA)를 합성하였다. 합성된 PEBA의 분자량과 기계적 성질 등을 비교 분석하였다.

• Elastomers and Composites
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• 제27권3호
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• pp.161-173
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• 1992

A series of polyurethane block copolymers based on hydroxyterminated poly(dimethyl siloxane), poly(propylene glycol) and poly(tetramethylene glycol) soft segments of molecular weights 1,809, 2,000 and 2,000, respectively, were synthesized. The hard segments consisted of 4,4'-diphenylmethane diisocyanate and 1,4-butanediol as the chain extender. Samples with different molar ratios were prepared. We tried to synthesize poly(dimethyl siloxane)-based polyurethane(PDMS-PU) containing a hard block as major fraction and a soft block as minor fraction for preparing toughened rigid systems. After a study of the pure PDMS-PU, poly(propylene glycol)-based polyurethane(PPG-PU) and poly(tetramethylene glycol)-based polyurethane(PTMG-PU), (mixed polyol)-based block copolymers and blends between PDMS-PU, PPG-PU and PTMG-PU were prepared, and characterized by means of differential scanning calorimetry, tensile testing and scanning electron microscopy. In (mixed polyol)-based PU and in lower hard segment content blends, macro-phase separation was shown, but blends with higher hard segment contents showed significant reduction in amounts of phase separation.

• 센서학회지
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• 제29권4호
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• pp.237-242
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• 2020

This paper deals with relative position estimation using a Kalman filter (KF) based on inertial sensors that have been widely used in various biomechanics-related outdoor applications. In previous studies, the relative position is determined using relative orientation and predetermined segment-to-joint (S2J) vectors, which are assumed to be constant. However, because body segments are influenced by soft tissue artifacts (STAs), including the deformation and sliding of the skin over the underlying bone structures, they are not constant, resulting in significant errors during relative position estimation. In this study, relative position estimation was performed using a KF, where the S2J vectors were adopted as time-varying states. The joint constraint and the variations of the S2J vectors were used to develop a measurement model of the proposed KF. Accordingly, the covariance matrix corresponding to the variations of the S2J vectors continuously changed within the ranges of the STA-causing flexion angles. The experimental results of the knee flexion tests showed that the proposed KF decreased the estimation errors in the longitudinal and lateral directions by 8.86 and 17.89 mm, respectively, compared with a conventional approach based on the application of constant S2J vectors.

• Fibers and Polymers
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• 제4권3호
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• pp.114-118
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• 2003

The prepolymer and the final polyurethane (PU) block copolymer were synthesized by reacting 4,4-methylene bis(phenylisocyanate) with poly(tetramethylene glycol) and the prepolymer with 1,4-butanediol as a chain extender, respectively, to investigate the relation between phase separation and it's resulting properties. According to FT-IR data, the phase separation of hard and soft segments in the prepolymer and the PU block copolymer grew bigger by increasing the hard segment content, and the PU showed more dominant phase separation than the prepolymer. The heat of fusion due to soft segments decreased in both the prepolymer and the PU by increasing the hard segment content, whereas the heat of fusion due to hard segments increased in the PU did not appear in the prepolymers. The breaking stress and modulus of the prepolymer increased by increasing the hard segment content, and the elongation at break decreased gradually, and the PU showed the highest breaking stress and modulus at 58% hard segment content. However, the best shape recovery of the PU was obtained at 47% hard segment content due to the existence of proper interaction among the hard segments for shape memory effect. Consequently, the mechanical properties and shape memory effect of the PU were influenced by the degree of phase separation, depending on the incorporation of chain extender as well as the hard segment content.