• 폴리머
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• 제32권4호
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• pp.353-358
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• 2008

EPDM에 maleic anhydride를 그래프트시켜 말레화 EPDM(MEPDM)을 제조하고 여기에 양 말단에 hydroxyl기를 갖는 $\alpha$,$\omega$-poly(dimethylsiloxane)(PDMS)을 반응시켜 MEPDM-g-PDMS 공중합체를 제조하였다. MEPDM-g-PDMS와 HDFE 및 4-ethoxybenzoic acid로 표면처리된 MWCNT를 internal mixer에 가하고 $180^{\circ}C$에서 컴파운딩하여 MEPDM-g-PDMS/HDPE/CNT 복합체를 제조하였다. 복합체에서 CNT의 모폴로지를 전자현미경으로 측정한 결과 표면처리된 CNT를 사용한 경우가 분산이 균일하게 이루어졌으며 입자의 응집현상도 감소되는 것으로 나타났다. 온도변화에 따른 전기저항은 용융온도부근에서 전기저항이 급격히 증가하였으며 EtO-CNT의 함량을 15%로 하여 제조한 복합체의 경우가 PTC intensity가 2.3으로 가장 우수한 PTC 특성을 나타내었다.

• 한국포장학회지
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• 제8권2호
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• pp.39-43
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• 2002

Increasing use of plastics in food packaging materials has led to the issue of food-plastic packaging materials's mutual interactions. Although the plastic packaging materials are generally considered as inert, migration and sorption of fatty materials are some of the problems associated with their use. So, this work investigated the compatibility of three structurally different polymers, polypropylene (PP), polyethyleneterephthalate (PET) and ethylene vinyl alcohol copolymer (EVOH) with some structurally different food fats. The main goal was to study the sorption of food fats by the plastic films and to see what extent mechanical properties of the plastic films was affected by plasticization effect due to sorption of fatty materials. PP, PET, and EVOH films was immersed in pure triglycerides, and then extracted with hexane and analyzed for the amounts of fat migrated. The sorbed films were also investigated for change in mechanical properties. Result showed that structural factor of the films and fatty materials plays important role in th migration process. The fat with the simplest structure are migrated more easily that the fat with more complex structure. However, structural effect of migration was varied according to degree of crystallinity and density of plastic films. In addition to that, polarity of plastic film was affected migration of fatty materials significantly. Additional research is needed to justify the reason why migration of fatty materials into the films was affected by polarity and structural integrity.

• 폴리머
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• 제33권5호
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• pp.490-495
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• 2009

Maleated 폴리프로필렌과 에틸렌-글리시딜 메타크릴레이트-메틸 아크릴레이트의 공중합체를 반응성 상용화제로 사용하여 무정형 알파올레핀 고분자/무정형 폴리아미드 블렌드의 반응 상용화를 시도하였다. 무정형 폴리아미드와 상용화제간의 그래프트 반응 정도는 FT-IR, SEM 및 rheometer로 조사하였다. 반응상용화에 따른 블렌드의 기계적 물성 변화 및 하이드로카본 형태의 점착부여수지를 첨가한 블렌드의 접착강도는 만능시험기로 조사하였다.

• 대한화학회지
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• 제34권2호
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• pp.197-202
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• 1990

한쪽 말단에 히드록시 혹은 양말단에 아미노기를 갖는 폴리에틸렌글리콜(PEG)을 이용한 에스테르 교환 혹은 아미노 치환반응을 행하여 (PEG) grafted poly γ-benzyl L-glutamate (PBLG)를 합성했다. 이들의 점도 특성은 진한 용액내에서는 농도 감소에 따라 점도가 감소하다가 어느 이상 묽어지게 되면, 농도 감소에 따라 점도는 다시 증가했다. PEG를 함유하는 폴리펩티드 중합체의 젖음성은 동종 중합체보다도 향상 됐고, 이들 중합체 필름을 아미노에탄올과 표면반응시킨 결과, 물의 접촉각이 대폭적으로 작아져 표면에 수화겔이 형성됨을 알 수 있었다.

• 한국응용과학기술학회지
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• 제26권3호
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• pp.288-296
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• 2009

In this study, the silica-based hybrid material with high barrier property was prepared by incorporating ethylene-vinyl alcohol (EVOH) copolymer, which has been utilized as packaging materials due to its superior gas permeation resistance, during sol-gel process. In preparation of this EVOH/$SiO_2$ hybrid coating materials, the (3-glycidoxy-propyl)-trimethoxysilane (GPTMS) as a silane coupling agent was employed to promote interfacial adhesion between organic and inorganic phases. As confirmed from FT-IR analysis, the physical interaction between two phases was improved due to the increased hydrogen bonding, resulting in homogeneous microstructure with dispersion of nano-sized silica particles. However, depending on the range of content of added silane coupling agent (GPTMS), micro-phase separated microstructure in the hybrid could be observed due to insufficient interfacial attraction or possibility of polymerization reaction of epoxide ring in GPTMS. The oxygen barrier property of the mono-layer coated BOPP (biaxially oriented polypropylene) film was examined for the hybrids containing various GPTMS contents. Consequently, it is revealed that GPTMS should be used in an optimum level of content to produce the high barrier EVOH/$SiO_2$ hybrid material with an improved optical transparency and homogeneous phase morphology.

• Journal of Pharmaceutical Investigation
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• 제31권1호
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• pp.1-5
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• 2001

The aggregation behavior of nystatin (NYS) in the presence of pluronic F127, triblock copolymer of poly (ethylene oxide) (PEO) and poly (propylene oxide) (PPO), was measured and correlated with hemolytic activity. Antifungal activity was also studied using Saccharomyces cerevisiae as a model strain. The critical aggregation concentrations (CAC) of the drug were 50.1, 108.0, 134.2, 154.3, and $217.9\;{\mu}M$ at 0.1%, 0.5%, 1.0%, 1.5%, and 2.0% pluronic F127 solution, respectively. The levels of NYS required to start lysis of erythrocytes were about 80, 100, 125, 150, and $200\;{\mu}M$ at 0.1%, 0.5%, 1.0%, 1.5%, and 2.0% pluronic F127 solution, respectively. It was $50\;{\mu}M$ in the absence of the polymer. Minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of NYS-pluronic F127 lyophilizate were same at $3\;{\mu}g/ml$, while MIC and MFC of pure NYS are $3\;{\mu}g/ml$ and $12\;{\mu}g/ml$, respectively. By modulating the aggregation behavior of NYS, pluronic F127 was able to reduce the toxicity of the drug without compromising the MIC and MFC.

• Macromolecular Research
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• 제14권1호
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• pp.73-80
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• 2006

Sulfonated poly(ethylene glycol) (PEG-$SO_{3}$) grafted polyrotaxanes (PRx-PEG-$SO_{3}$) were prepared in order to utilize the unique properties of PEG-$SO_{3}$ and the supramolecular structure of PRx, in which PEG-$SO_{3}$ grafted $\alpha$-cyclodextrins ($\alpha$-CDs) were threaded onto PEG segments in a PEG-b-poly(propylene glycol) (PPG)-b-PEG triblock copolymer (Pluronic) chain capped with bulky end groups. Some of the PRx-PEG-$SO_{3}$ demonstrated a higher anticoagulant activity in case of PRx-PEG-$SO_{3}$ (P 105), and compared with the control they showed a lower fibrinogen adsorption in PRx-PEG-$SO_{3}$ (F68) and a higher binding affinity with fibroblast growth factor. The obtained results suggested that polyrotaxane incorporated with PEG-$SO_{3}$ may be applicable to the surface modification of clinically used polymers, especially for blood/cell compatible medical devices.

• Bulletin of the Korean Chemical Society
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• 제25권8호
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• pp.1182-1188
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• 2004

Polydisperse oligo(PO-b-EO) allyl ether siloxane surfactants were synthesized by the hydrosilylation reaction of OMTS with Allyl-oligo(PO-b-EO) series. The surface tension of siloxane surfactants increased with increasing the EO chain length while it decreased with increasing the PO ratio. However, the sedimentation time of the aqueous solution showed opposite trend to the surface tension data. Both the surface tension and sedimentation time of the aqueous solution containing inorganic electrolyte gradually decreased as the content of inorganic electrolyte increased because of the surface arrangement of surfactant molecules. However, they increased with an increase of pH values due to the hydrolysis of the siloxane backbone. The $C_p$ values tended to increase with the increase in the EO chain length and decrease of the PO ratio. It seems that intermolecular interaction between PO/EO block copolymer and water affects the variation of transition temperature.

• 한국산학기술학회논문지
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• 제12권4호
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• pp.1988-1992
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• 2011

폴리프로필렌(polypropylene, PP)-SEBS(styrene-ethylene/butylene-styrene triblock copolymer)/실리케이트 복합체를 PP의 조성을 35, 40 그리고 45wt%로 변화시키며 실험실 규모의 Brabender Mixer를 이용하여 $200^{\circ}C$에서 용융상태에서 제조하였다. 실리케이트 조성은 5wt%로 고정하였다. PP-SEBS/실리케이트 복합체의 열적특성을 DSC와 TGA를 이용하여 분석하였다. PP-SEBS 콤파운드의 용융온도는 SEBS 함량에 따라 $141^{\circ}C$까지 감소하였다. 실리케이트가 PP-SEBS에 첨가되었을 때 분해온도가 증가하는 것을 TGA 결과로부터 확인할 수 있었다. 콤파운드의 유변학적 특성을 동적유변측정기를 이용하여 측정하였다. PP-SEBS/실리케이트 복합체는 PP-SEBS 콤파운드보다 shear thinning과 탄성특성이 증가하였다. 탄성특성 증가를 확인하기 위해 Van Gurp-Palmen 분석을 이용하였다.

• Macromolecular Research
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• 제16권2호
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• pp.169-177
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• 2008

This paper reports a facile synthesis of new water-soluble poly(ethylene oxide) (PEO)-based amphiphilic block copolymers showing pH sensitive phase transition behaviors. The copolymers were prepared by atom transfer radical polymerization (ATRP) of methacrylamide type of monomers carrying a sulfonamide group using a PEO-based macroinitiator and a Cu(I)Br/$Me_6TREN$ catalytic system in aqueous media. The resulting polymers were characterized by a combination of $^1H$-NMR, size exclusion chromatography, and UV/Visible spectrophotometeric analysis. The micellization of the block copolymers as a drug-loading mechanism in aqueous media using fluorescein salt was examined as a function of pH. The stable micelle formation and its loading efficacy suggest that the block copolymers can be used as precursors for drug-nanocontainers.