• Fibers and Polymers
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• 제4권4호
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• pp.156-160
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• 2003

Poly(ethylene 2,6-naphthalate) (PEN)/Poly(ethylene glycol) (PEG) copolymers were synthesized by two step reaction during the melt copolymerization process. The first step was the esterification reaction of dimethyl-2,6-naphthalenedicarbox-ylate (2,6-NDC) and ethylene glycol (EG). The second step was the condensation polymerization of bishydroxyethylnaphthalate (BHEN) and PEG. The copolymers contained 10 mol% of PEG units with different molecular weights. Structures and thermal properties of the copolymers were studied by using $^1{H-NMR}$, DSC, TGA, etc. Especially, while the intrinsic viscosities of PEN/PEG copolymers increased with increasing molecular weights of PEG, but the glass transition temperature, the cold crystallization temperature, and the weight loss temperature of the copolymers decreased with increasing molecular weights of PEG. Consequently, the hydrophilicities by means of contact angle measurement and moisture content of the copolymer films were found to be significantly improved with increasing molecular weights of PEG.

• 폴리머
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• 제30권6호
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• pp.512-518
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• 2006

양친성 블록공중합체는 생분해성 고분자인 poly((R)-3-hydroxybutyrie acid), PHB와 친수성 고분자인 poly(ethylene glycol), PEG를 이용하여 제조되었다. 미생물에 의해 생산된 분자량이 수십만인 PHB는 약물전달용 재료로 적합하지 않으므로 산 촉매 가수분해를 통해 분자량이 $3000{\sim}30000$을 가지도록 조절되었다. 공중합체를 수용액에 넣으면, 고분자들은 자기 조립에 의해 친수성인 PEG가 소수성인 PHB를 감싸는 형태의 고분자 미셀을 형성한다. 형성된 고분자 미셀은 생분해성과 생체적합성을 가지면서 생체 내에서 낮은 독성과 환자 친화적인 특성을 가지므로 약물 전달체로의 이용이 가능하다. 양친성 블록 공중합체는 PHB에 PEG를 도입한 것으로 에스테르교환(transesterification) 반응을 통해 유도되었다. PEG는 친수성 블록의 형성과 반응성을 향상시키기 위해 말단의 작용기를 개질한 후 사용되었다. 양친성 블록 공중합체 형성에 대한 열적 특성과 화학적 구조 분석은 DSC, FTIR, $^1H-NMR$을 사용하여 알아보았다. 임계 미셀 농도(critical micelle concentration, CMC)는 고분자 미셀이 형성되는 시점으로 형광 분광기를 사용하여 분석한 결과 $5{\times}10^{-5}g/L$ 부근에서 측정되었다. 수용액 상의 고분자 미셀은 냉동 건조 후, 분말형태의 나노입자를 얻었다. 고분자 미셀의 크기는 dynamic light scattering으로 측정한 결과 약 130 nm 정도로 나타났다. 또한 atomic force microscopy 측정을 통해 크기가 약 130 nm 정도인 구형 입자를 확인하였다. 나노입자가 형성된 고분자 미셀은 소수성 약물을 담지하여 수동적 표적지향형 약물 전달용 수송체로 이용이 가능할 것이다.

• 멤브레인
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• 제29권4호
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• pp.223-230
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• 2019

본 논문에서는 이산화탄소 친화적인 PBEM-POEM (PBE) 공중합체를 기반으로 고분자 블렌드 분리막을 제조하는 방법을 제시한다. PBE 공중합체는 자유 라디칼 중합 반응을 통해 손쉽게 합성이 가능하며, 이를 상용 고분자인 PEG와 다양한 비율로 혼합하여 이산화탄소/질소 분리막을 제조하였다. 이산화탄소/질소 분리 성능을 테스트한 결과, PEG의 함량이 높을수록 이산화탄소 투과도는 감소하는 반면 이산화탄소/질소 선택도는 크게 증가하는 상충(trade-off) 관계가 나타났다. 그러나 PBE/PEG (9 : 1)과 PBE/PEG (7 : 3)을 비교하면 이산화탄소 투과도는 단지 8.3% 감소한 반면에 질소 투과도는 69.1%나 감소하였다. 따라서 이산화탄소/질소 선택도가 33.8에서 100.3으로 크게 증가하였다. 이것은 PBE 공중합체의 80%를 차지하는 POEM 사슬이 PEG와 상호작용하여 더욱 조밀한 구조가 되었기 때문이며, 이를 FT-IR, XRD, SEM 분석으로 확인하였다. PBE/PEG (7 : 3) 블렌드 막이 가장 최적의 기체 분리 성능을 가졌고, 이산화탄소투과도는 170.5 GPU, 이산화탄소/질소 선택도는 100.3이었다.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.263-263
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• 2006

Poly (ethylene glycol)(PEG) - Poly (${\varepsilon}-caprolactone(CL)$) - Poly (D,L lactide(LA) (PCLA-PEG-PCLA) was synthesized by ring-opening polymerization to form temperature sensitive hydrogel triblock copolymer. The triblock copolymer was acrylated by acryloyl chloride. ${\beta}-amino$ ester was used as a pH sensitive moiety, in this study ${\beta}$- amino ester obtained from 1,4-butandiol diacrylate, and 4, 4' trimethylene dipiperidine, it have pKb around 6.6. pH/temperature sensitive penta-block copolymer (PAE-PCL-PEG-PCL-PAE) was synthesized by addition polymerization from acrylated triblock copolymer, 1,4-butandiol diacrylate, and 4, 4' trimethylene dipiperidine. Their physicochemical properties of triblock and penta-block copolymers were characterized by $^1H-NMR$ spectroscopy and gel permeation spectroscopy. Sol-gel phase transition behavior of PAE-PCL-PEG-PCL-PAE block copolymers were investigated by remains stable method. Aqueous media of the penta-block copolymer (at 20 wt%) changed from a sol phase at pH 6.4 and $10^{\circ}C$ to a gel phase at pH 7.4 and $37^{\circ}C$. The sol-gel transition properties of these block copolymers are influenced by the hydrophobic/hydrophilic balance of the copolymers, block length, hydrophobicity, stereo-regularity of the hydrophobic of the block copolymer, and the ionization of the pH function groups in the copolymer depended on the changing of environmental pH, respectively. The degradation and the stabilization at pH 7.4 and $37^{\circ}C$, and the stabilization at pH 6.4 and $10^{\circ}C,\;5^{\circ}C,\;0^{\circ}C$, of the gel were determined. The results of toxicity experiment show that the penta block copolymer can be used for injection drug delivery system. The sol?gel transition of this block copolymer also study by in vitro test ($200{\mu}l$ aqueous solution at 20wt% polymer was injected to mouse). Insulin loading and releasing by in vitro test was investigated, the results showed that insulin can loading easily into polymer matrix and release time is around 14-16days. The PAE-PCL-PEG-PCL-PAE can be used as biomaterial for drug, protein, gene loading and delivery.

• Macromolecular Research
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• 제12권4호
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• pp.342-351
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• 2004

Poly(ethylene glycol) (PEG1K) and sulfonated PEG (PEG1K-SO$_3$) methacrylate (MA) copolymers have been prepared and characterized. The structures of the synthesized copolymers were confirmed by $^1$H and $^{13}$ C NMR spectroscopy and elemental analysis. The bulk characteristics of the copolymers were evaluated by viscosity and thermal analysis. The surface properties of the copolymers were investigated using dynamic contact angle measurements and electron spectroscopy for chemical analysis. The hydrophilicity of the surfaces modified with PEG1KMA or PEG1K-SO$_3$MA increased, possibly as a result of the orientation of the hydrophilic PEG1KMA/PEG1K-SO$_3$MA chains into the water phase. Platelets adhered less to the surfaces of the copolymers than they did to a polyurethane control. In addition, adhesion of platelets to the copolymer surfaces decreased upon increasing the chain density of PEG1KMA and sulfonated PEG1KMA in the copolymers. Both bacterial adhesion and protein adsorption were significantly reduced on the copolymer surfaces and their levels differ depending on the kind of surface or media.

• Journal of Electrochemical Science and Technology
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• 제1권1호
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• pp.57-62
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• 2010

The lithium ion concentration dependant ionic conductivity and thermal properties of poly(ethylene glycol) methyl ether methacrylate (PEGMA)/acrylonitrile-based copolymer electrolytes with $LiClO_4$ have been studied by differential scanning calorimetry (DSC), linear sweep voltammetry (LSV) and AC complex impedance measurements. In systems with 11 wt% of acrylonitrile all liquid electrolytes were obtained regardless of lithium ion concentration. Complex impedance measurements with stainless steel electrodes give ambient ionic conductivities $8.1\times10^{-6}\sim1.4\times10^{-4}S cm^{-1}$. On the other hand, a hard and soft films at ambient temperature were obtained in copolymer electrolyte system consists of 15 wt% acrylonitrile with 6 : 1 and 3 : 1 of [EO] : [Li] ratio, respectively. DSC measurements indicate the crystalline melting temperature of poly(PEGMA) disappeared completely after addition of $LiClO_4$ in this system due to the complex formation between ethylene oxide (EO) unit and lithium salt. As a result, free standing film with room temperature ionic conductivity of $1.7\times10^{-4}S cm^{-1}$ and high electrochemical stability up to 5.5V was obtained by controlling of acrylonitrile and lithium salt concentration.

• Macromolecular Research
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• 제11권5호
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• pp.341-346
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• 2003

A poly(ethylene oxide)-b-poly(L-lactide) diblock copolymer (PEO-b-PLLA) is characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and a block length distribution map is constructed. Although the MALDI- TOF mass spectrum of PEO-b-PLLA is very complicated, most of the polymer species were identified by isolating the overlapped isotope patterns and by fitting the overlapped peaks to the Schulz-Zimm distribution function. Reconstructed MALDI-TOF MS spectrum was nearly identical to the measured spectrum and this method shows its potential to be developed as an easy and fast analysis method of low molecular weight block copolymers.

• Bulletin of the Korean Chemical Society
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• 제19권9호
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• pp.962-967
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• 1998

Block copolymers consisting of poly(rbenzyl L-glutamate) (PBLG) as the hydrophobic part and poly(ethylene oxide) (PEO) as the hydrophilic part were synthesized and characterized. Polymeric micelles of the block copolymers (abbreviated GEG) were prepared by a dialysis method. The GEG block copolymers were associated in water to form polymeric micelles, and the critical micelle concentration (CMC) values of the block copolymers decreased with increasing PBLG chain length in the block copolymers. Transmission electron microscopy (TEM) observations revealed polymeric micelles of spherical shapes. From dynamic light scattering (DLS) study, sizes of polymeric micelles of GEG-1, GEG-2, and GEG-3 copolymer were 106.5±59.2 nm, 79.4±46.0 nm, and 37.9±13.3 nm, respectively. The drug loading contents of GEG-1, GEG-2 and GEG-3 polymeric micelles were 12.6, 11.9, and 11.0 wt %, respectively. These results indicated that the drugloading contents were dependent on PBLG chain length in the copolymer; the longer the PBLG chain length, the more the drug-loading contents. Release of norfloxacin (NFX) from the nanoparticles was slower in higher loading contents of NFX than in lower loading contents due to the hydrophobic interaction between PBLG core and NFX.

• 대한화학회지
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• 제59권2호
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• pp.142-147
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• 2015

Two new chitosan derivatives, polyamine grafted chitosan copolymers have been synthesized for corrosion protection of carbon steel in acidic medium. First, methyl acrylate graft chitosan copolymer (CS-MAA) was prepared by the reaction of chitosan (CS) and methyl acrylate (MAA) via the Michael addition reaction. Then, CS-MAA was reacted with ethylene diamine (EN) and triethylene tetramine (TN) respectively to synthesize ethylene diamine grafted chitosan copolymer (CS-MAA-EN) and triethylene tetramine grafted chitosan copolymer (CS-MAA-TN), and the structures were characterized by Fourier-transform infrared spectroscopy (FT-IR). At last, the corrosion inhibition activities on Q235 carbon steel were investigated by using gravimetric measurements, metallographic microscope, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. The compounds CS-MAA-EN and CS-MAA-TN show an appreciable corrosion inhibition property against corrosion of Q235 carbon steel in 5% HCl solution at $25^{\circ}C$. It has been observed that CS-MAA-EN shows greater corrosion inhibition efficiency than CS-MAA-TN. The inhibition efficiency of CS-MAA-EN was close to 90% when the mass fraction concentration was 0.2%~0.3%; the inhibition efficiency of CS-MAA-TN was close to 85% when the mass fraction concentration was 0.02%. The present work provided very promising results in the preparation of green corrosion inhibitors.

• 한국포장학회지
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• 제16권1호
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• pp.5-7
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• 2010

Two kinds of polymer coating (acrylic polymer and vinyl acetate ethylene copolymer) added with 5% nisin were fabricated on the paperboards and tested in their antimicrobial activity against Micrococcus flavus ATCC 10240 inoculated into water contacting the coating at $10^{\circ}C$. Vinyl acetate ethylene copolymer giving faster and higher nisin migration presented the greater reduction in the microbial count than the other coating, which endorsed that the migrated nisin is mainly responsible for the microbial inhibition or destruction. There was also a slight effect of the coating polymer itself in the microbial inhibition.