• 폴리머
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• 제24권2호
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• pp.211-219
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• 2000

액정성을 가지는 플로렌계 발광고분자에 비버정성 플로렌계 발광고분자를 첨가한 블렌드를 제조하여 에너지전달 효과와 흡광 및 발광 이방성에 대하여 고찰하였다. 비액정성 고분자를 액정성 고분자에 0.5wt% 첨가하고 360nm로 여기한 결과, 420nm에서 관찰되었던 액정성 고분자의 발광피크는 거의 사라졌으며 대신 비액정성 고분자에 의한 480nm에서의 새로운 발광피크가 관찰되었다. 블렌드 시료의 480nm 발광은 비액정성 고분자가 2.0wt% 첨가되었을때 가장 강했으며, 발광강도는 블렌딩 이전의 각 고분자보다 13배 증자하였다. 블렌드내의 분자들을 마찰 폴리이미드 기판상에서 가열-냉각시켜 배향시키면 시료의 발광 이방성과 order parameter는 각각 2.0 및 0.25를 나타내었다. 시간 상관 단광자 계수법 (TCSPC)에 의해 고찰한 결과, 마찰 폴리이미드 기판상에서의 배향에 의해 두 발광고분자간의 에너지전달에 필요한 시간은 93 ps만큼 단축되며 에너지전달 효율은 9% 증가함을 알 수 있었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.641-644
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• 2009

We demonstrated a solvent-assisted soft-lithographic patterning method for producing patterned structure and patterned ordering with lyotropic liquid crystalline polymer (LCP) film. Experimental results showed that the liquid crystalline ordering of lyotropic film could be controlled by shearing effects of the fluidic solvent though the patterned mold channels. In this work, two types of lyotropic LCPs were used to investigate the effects of the alkyl chain length of the lyotropic LCP on producing liquid crystalline ordering through the solvent-assisted fluidic patterning.

• Macromolecular Research
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• 제11권4호
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• pp.224-230
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• 2003

The blends of polypropylene (PP) with glass filled thermotropic liquid crystalline polymer (LCP-g) have been prepared by melt mixing techniques at different blend ratios. The thermal, dynamic mechanical, crystalline and morphological characteristics of these blends were investigated. Higher percent crystallinity was observed for 10% level of LCP-g in the blend in comparison to that of other blend ratios. The thermal stability increased with LCP-g concentration in the blend with PP. The variation of storage modulus, stiffness and loss modulus as a function of blend ratios suggested the phase inversion at the 50% level of LCP-g in the blend. The scanning electron microscopy (SEM) photographs showed the creation of voids and destruction of the fiber structures during the dynamic mechanical measurements. Processing behavior of the blends depended on the fiber forming characteristics of LCP-g, which again varied with the molding temperatures.

• 폴리머
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• 제35권2호
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• pp.176-182
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• 2011

방향족 액정 폴리에스테르는 열방성 액정 중합체의 대표저인 예로 지금까지 구조-물성 관계가 많이 연구되었다. 본 연구에서는 유기 용매에 녹일 수 있는 가용성 방향족 액정 폴리에스테르를 합성하고, 아세틸렌 말단기를 갖는 열경화성 수지와 복합화하여 제반 물성을 비교하였다. 가용성 방향족 액정 폴리에스테르는 6-hydroxy-2-naphthoic acid, terephthalic acid, isophthalic acid 및 4-aminophenol을 단량체로 하여 에스테르 및 아미드 교환 반응에 기초로 한 축합 중합법을 이용하여 합성하였다. 아세틸렌 말단기를 갖는 열경화성 수지는 4-ethynylaniline과 terephthaloyl dichloride, isophthaloyl clichloride, 4,4'-biphenyldicarbonyl dichloride 등과 각각 반응시켜 합성하였다. 가용성 방향족 액정 폴리에스테르와 열경화성 수지를 용액 블렌딩하고 열처리하여 복합체를 제조하였으며, 복합체의 열적 안정성, 열팽창계수, 유전특성 등을 조사하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1266-1267
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• 2008

Liquid crystalline polymer BB-3(1-methyl) takes two kinds of glass phases which are liquid crystalline glass and liquid glass below the glass temperature. This study is aimed to analyze the phase transitions of those samples with variation of temperature. For the analyzing temperature dispersion of dielectric constants was measured and the results were analyzed.

• Fibers and Polymers
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• 제1권2호
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• pp.83-91
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• 2000

Thermotropic liquid crystalline polymer made up of poly(p-hydroxybenzoate) (PHB)-poly(ethylene terephthalate)(PET) 8/2 copolyester, poly(ethylene 2,6-naphthalate) (PEN) and PET were mechanically blended to pursue the liquid crystalline phase of ternary blends. Complex viscosities of blends decreased with increasing temperature and PHB content. DSC thermal analysis indicated that glass transition temperature (Tg) and melting temperature (Tm) of blends increased with increasing PHB content. Both tensile strength and initial modulus increased with raising PHB content and take-up speed of monofilaments. In the WAXS diagram, only PEN crystal reflection at 2Θ=$15.5^{\circ}C$ appeared but PET crystal reflection was not shown in all compositions. The degree of transesterification and randomness of blends increased with blending time but sequential length of both PEN and PET segment decreased.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.90-90
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• 2006

Mesogen-Jacketed Liquid Crystalline Polymers, MJLCPs, are polymers with mesogenic side groups directly attached to main-chains without using flexible connecting spacers and are able to form liquid crystalline structures. Later work on structure-property of the polymers revealed that the side groups are not necessarily mesogenic for the polymers to form a mesophase so long as that the side groups are directly attached to the backbones and the side groups are large enough. Because of its inherent chain stiffness and that the monomers of MJLCPs are readily polymerizable by "living" free radical polymerizations, MJLCP offered a unique handy tool for making block copolymers. In addition, MJLCP offered also new opportunities for novel functional materials.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.345-345
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• 2006

It is well known that poly(glutamate)s with long n-alkyl side chains form thermotropic liquid crystalline state by melting of the side-chain crystallites and also poly(glutamate)s such as poly(${\gamma}-benzyl\;L-glutamate$ )(PBLG), poly(${\gamma}-n-alkyl\;L-glutamate$), etc. in solvent form the isotropic, biphasic and liquid crystalline phases which contains cholesteric and columnar liquid crystalline forms depending on the polypeptide concentration. Although there is no diffusion study for PBLG in liquid crystalline state, because it is difficult to observed $^{1}H$ spectrum of PBLG in liquid crystalline state for its very short $^{1}H\;T_{2}$. In this study, the diffusional behavior of rodlike PBLG in concentrated solution is successfully elucidated as studied by the field-gradient $^{1}H$ NMR methods.

• Macromolecular Research
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• 제13권1호
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• pp.19-29
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• 2005

Polymer composites based on a thermotropic liquid-crystalline polymer (TLCP) and poly(butylene terephthalate) (PBT) were prepared using a melt blending process. Polymer composites consisting of bulk cheap polyester with a small quantity of expensive TLCP are of interest from a commercial perspective. The interactions between the PBT chains and the flexible poly(ethylene terephthalate) (PET) units in the TLCP phase resulted in an improvement in the compatibility of PBT/TLCP composites. TLCP droplets deformed and fragmented into smaller droplets in the PBT/TLCP composites, which resulted in TLCP fibrillation through the effective deformation of the TLCP droplets. The nucleation activities of the PBT/TLCP composites increased by adding even a small amount of the TLCP component.

• Elastomers and Composites
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• 제52권3호
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• pp.173-179
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• 2017

Side-chain liquid crystalline polymers having polysiloxane skeletons were synthesized by a thiol-ene reaction, using two kinds of mesogenic groups: a cholesteryl group for induction into a cholesteric liquid crystal phase and a triazomesogenic group for imparting light-sensitivity. All the synthesized polymers were crystalline, except the one with a single cholesteryl group. Crystallinity, glass transition temperature, and melt transition temperature increased with increasing content of the azomesogenic group. The polymer (P-C10A0) with a single cholesteryl group has a cholesteric phase, the one (P-C0A10) with a single azomesogenic group has a smectic phase, and those with both types of mesogenic groups showed both smectic and cholesteric phases. The temperature ranges of the two liquid crystalline phases in the co-polymers were independent of the contents of the two types of mesogenic groups. The rate of photoisomerization of the light-sensitive azobenzene group in the polymer decreased with increasing azobenzene content due to steric hindrance between the azomesogenic groups.