• Journal of Welding and Joining
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• 제33권4호
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• pp.44-49
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• 2015

The structural epoxy adhesive used in car body assembly needs the highest level of joint mechanical strength under lap shear, T-peel and impact peel conditions. In this study, the effect of nano functionalized block copolymer addition on the impact peel strength of epoxy adhesive was investigated. DSC analysis showed that the addition of nano functionalized block copolymer did not affect the curing reaction of epoxy adhesive. From single lap shear test, it was found out that the addition of nano functionalized block copolymer slightly decreased the cohesive strength of cured adhesive layer. The addition of nano functionalized block copolymer showed beneficial effect on T-peel strength by changing the adhesive failure mode to the mixed mode. However, the addition of nano functionalized block copolymer just decreased the room temperature impact peel strength. It was considered that the addition of nano functionalized block copolymer could have effect on disturbing the crack propagation only for the case of slow strain rate.

• 대한화학회지
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• 제27권3호
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• pp.189-193
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• 1983

리튬동위원소의 분리 실험이 염산과 양이온 교환 수지를 사용하여 행하여졌다. 이 실험에서는 porous sulfonated styrene-divinylbenzene copolymer와 Dowex 50w-x8의 양이온 교환수지가 사용되었다. 리튬의 양은 원자 흡광 분석기를 사용하여 측정되었다. 리튬 동위 원소의 상대적 질량은 질량 분석기로 측정하였다. 동위 원소의 분리인자는 분별된 용출액의 동위 원소 조성으로 부터 계산되었다. 분리 인자의 값은 염산과 porous sulfonated styrene-divinylbenzene copolymer system에서 1.0020이었고, 염산과 Dowex 50w-x8 system에서 1.0011${\om}$0.0002이었다. 이와 같은 결과로부터 우리들은 분리 인자의 값이 Dowex 50w-x8에서 보다 porous sulfonated styrene-divinylbenzene copolymer에서 더 크게 나타남을 알 수 있었다.

• 대한의용생체공학회:의공학회지
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• 제12권1호
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• pp.57-62
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• 1991

ABA type block copolymers composed of poly($\gamma-benzyl$ L-glutamate) (PBLG) as the A component and poly (ethylene glycol) as the B component were obtained by polymerization of $\gamma-benzyl$ L-gletamate N -carboxyanhydride, initiated by amino groups at both ends of poly(ethylene glycol) . From circular dichroism measurements in ethylene dichloride solution as well as from infrared spectTa measurements in solid state, it was found that the polypep- tide block exists in the a-helical conformation, as in PBLG homopolymer. $Poly-N^5$ (3-hydroxypropyl glutamine) (PHPG)/poly(ethylene glycol)block copolymer hydrogel was obtained by the treatment of PBLG/PBG block copolymer with the mixture of 3-ammine-1-propanol and diamlnooctane. The water content of PHPG/PEG block copolymer hydrogel was about 80wt% when the concentration of crosslinking agent was below 5 mole % per polymer.

• 대한의용생체공학회:의공학회지
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• 제8권2호
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• pp.199-204
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• 1987

ABA type block copolymers composed of r benzyle L-glutamate as the A component and poly(ethylene glycol) as the B components were obtained. Platelet adhesion on their sunfaces was investigated by a column elusion method to examine the effects of microdomain and secondary structure. The number of platelets adhered from whole blood and plasma rich platelet was smaller for the block copolymer systems than for the homopolymers. In the block copolymer system, the number of platelets adrered on their surfaces increased with increasing the content of PEG, that is, with decreasing of a-helix of block copolymers. A thick thrombus formation on the PBLG homopolymer was observed than block copolymer by scanning electron micrographs. The platelets adhesion increased with increasing the critical surface tension of the block copolymer.

• 한국응용과학기술학회지
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• 제19권4호
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• pp.273-280
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• 2002

Thermal decomposition of the copolymer of butyl methacylate(BMA) with styrene(St) was investigated. The copolymer Was obtained at 80 $^{\circ}C$ in a continuous stirred tank reactor(CSTR) using toluene and benzoyl peroxide(BPO), as solvent and initiator, respectively. The reactor volume was 0.3 liters and residence time was 3 hours. The thermal decomposition followed the second order kinetics for BMA/St copolymer. The activation energies of thermal decompositon were in the ranges of 38 ${\sim}43$ kcal/mol for BMA with St copolymer and a good additivity rule was observed with the composition of copolymer. The thermogravimetric trace curve agreed well with the theoretical calculation.

• Journal of Microbiology and Biotechnology
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• 제14권1호
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• pp.193-196
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• 2004

The peptide Arg-Gly-Asp (RGD) was immobilized through their amino terminus to ends of a sugar bearing copolymer, producing a functional hybrid copolymer. Poly(N-p-vinylbenzyl-D-maltonamide-co-6-(p-vinylbenzamido)-hexanoic acid-g-GRGDS) [p(VMA-co-VBGRGDS)] promoted the attachment and growth of NIH fibroblast cells. The interaction between fibroblast cells and p(VMA-co- VBGRGDS) copolymer resulted in effective cell attachment, proliferation, and morphological changes by introduction of a GRGDS sequence. Moreover, when pretreated with soluble RGD monomer, attachment of fibroblast cells was suppressed approximately 50% from that of the p(VMA-co-VBGRGDS) surface.

• Korean Chemical Engineering Research
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• 제46권1호
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• pp.15-22
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• 2008

최근 메탈로센 촉매를 통한 올레핀 합성 기술의 발달로 폴리올레핀 블록공중합체를 제조할 수 있는 기술이 개발되었으며 향후 고분자 산업에 크게 기여할 것으로 기대되고 있다. 하지만 현재까지 폴리올레핀 블록공중합체의 특성에 대한 체계적인 연구가 보고되고 있지 못한 실정이다. 본 리뷰 논문에서는 결정질의 poly(ethylene) (E) 블록과 고무질(rubbery)의 블록을 가지는 선형 폴리올레핀 블록공중합체를 통하여 폴리올레핀 블록공중합체의 열가소성 탄성체로서의 열역학적, 기계적 특성 및 분자 구조의 효과 특성 등에 관하여 살펴보고자 한다.

• Macromolecular Research
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• 제11권1호
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• pp.42-46
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• 2003

Cell attachment and proliferation on the polymer films of triblock copolymer(ester-ether)s comprising po1y (L-1actide) (PLLA) and poly (oxyethylene-co-oxypropylene)(PN) were investigated using 3T3 fibroblasts. It was found that on the tissue culture polystyrene(TCPS) and the PLLA control film the cells could spread well while on the copolymer films the cells showed a rounded morphology without spreading and proliferated weakly. Especially, little cells proliferated on the films of copolymer having a LN composition of 20 wt%. While the water absorption of the copolymer films increased with increasing PN content, the contact angle against water of copolymer films immersed in aqueous medium was almost identical, being slightly lower than that of the PLLA film. These properties were compatible with the results of cell attachment. The in vitro hydrolysis of the films of triblock and multiblock type copolymers was faster with increasing PN content. The increased hydrolyzability, the flexibility and the decreased cell attachment suggested that these copolymers may have high potential as biodegradable materials for medical use.

• Macromolecular Research
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• 제17권4호
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• pp.271-275
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• 2009

This paper describes the out-of-plane order of a liquid crystalline(LC) methacrylate copolymer(3) comprised of a methacrylate(1) with a 4-styrylpyridine moiety as the photo-cyclodimerizable group and a benzoate moiety as the mesogenic group in the side chain, and another methacrylate(2) with a 4-(4-methoxyphenyl)benzoate moiety as the mesogenic group. The composition of 1 and 2 units in 3 was estimated to have a molar ratio of 54.2:45.8 by $^{1}H$ NMR spectroscopy. The X-ray diffraction study revealed that the copolymer forms a partial bilayer smectic structure. The copolymer gave rise to a high out-of-plane order parameter of about 0.74 in a wide LC temperature range of $110{\sim}160^{\circ}C$ after linearly polarized, UV light irradiation and subsequent annealing. Moreover, the external reflection IR analysis indicated that excess UV-light irradiation makes the out-of-plane LC structure of the copolymer appear in a higher and wider temperature range.

• 공업화학
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• 제29권4호
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• pp.395-398
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• 2018

전기장 하에서 유기물은 전기장에 의해 부여된 여러 가지 힘의 영향을 받아서 특이한 거동을 나타낸다. 본 연구에서는, 지금까지 개별적으로 고찰되어 왔던 전기장 하에서의 블록 공중합체와 고분자 블렌드의 미세 거동을 비교 분석하여 특징적인 차이점을 알아보고자 한다. 두 가지 고분자가 공유결합으로 연결된 블록 공중합체와 약한 상호작용으로 혼합된 고분자 블렌드 시스템을 비교대상으로 하였다. 이때, 구성 고분자로는 비슷한 유전상수를 갖는 폴리아크릴로 나이트릴과 폴리메틸메타아크릴레이트를 도입하였다. 유사한 분자량, 같은 농도, 같은 전기장 세기하에서 고분자 블렌드가 전기장에 더욱 민감하게 반응하는 것을 알 수 있었다. 이는 공유결합이 분자의 운동성을 제약하여 전기장에 덜 민감하게 반응하도록 거동하기 때문이다. 본 연구는 고분자 물질의 전기장 하에서의 거동을 이해하는 중요한 정보를 제공할 것이다.