• Bulletin of the Korean Chemical Society
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• 제22권1호
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• pp.110-112
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• 2001

• Macromolecular Research
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• 제12권1호
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• pp.32-37
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• 2004

The atom transfer radical polymerization (ATRP) of hexadecyl acrylate (HDA) was carried out in Ν,Ν-dimethylformamide (DMF) in the presence of CuSCN/Ν,Ν,Ν′,Ν"Ν"-pentamethyldiethylenetriamine (PMDETA). The results indicate that the polymerization is well-controlled: a linear increase of molecular weights occurs with respect to conversion and the polydispersities are relatively low. In particular, the use of CuSCN as the catalyst resulted in faster polymerization rates for hexadecyl acrylate than did those using either CuBr or CuCl; the polydis-persity, however, was larger than those obtained in the cases when CuBr and CuCl were used. In addition, we report the thermodynamic data and activation parameters for the solution ATRP of hexadecyl acrylate.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.320-320
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• 2006

The authors report the synthesis and radical ring-crossover polymerization of macrocycles with radically exchangeable dynamic covalent bonds. The macrocyclic compounds with alkoxyamine units were designed and synthesized by condensation from alkoxyamine-based diol and the corresponding acid chlorides in the presence of pyridine under high-dilution condition. The macrocycles can thermally polymerize by intermolecular radical crossover reaction. Furthermore, the poly(alkoxyamine)s depolymerized to the monomers principally by the intramolecular radical exchange process under high-dilution conditions.

• Korean Chemical Engineering Research
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• 제49권5호
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• pp.676-680
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• 2011

스티렌과 메틸아크릴레이트(methyl acrylate, MA)를 원자라디칼이동 중합(atom radical transfer polymerization, ATRP)에서 주요한 중합공정 조건인 투입되는 MA 몰분율, 중합 온도, 중합 시간이 미치는 영향을 조사하였다. MA 몰분율이 증가할수록 분자량은 증가하고 중합시간이 3시간일 때 중합용액의 초기 모노머 몰 비와 생성되는 고분자의 조성비가 거의 선형 관계를 갖는다. 중합시간이 증가함에 따라 공중합체의 분자량은 증가하고, 공중합체의 MA 조성비가 감소함을 알 수 있다. 이를 통해 스티렌-MA 공중도 ATRP의 리빙 라디칼 중합 특징을 보이고 있음을 알 수 있다. 중합온도가 증가함에 따라 공중합체의 분자량은 크게 증가하고, 특히 $110^{\circ}C$의 고온에서 공중합체 내에 MA 조성비가 크게 증가함을 볼 수 있다.

• Macromolecular Research
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• 제13권3호
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• pp.229-235
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• 2005

Various alkoxyamine initiators for nitroxide mediated radical polymerization (NMRP) were prepared in high yields by a simple substitution reaction of nitroxide anions with benzyl bromide. The required nitroxide anions were easily generated by treating either nitroxide free radicals or hydroxy amine with an alkali metal such as sodium or potassium in THF. This method is both practical and efficient, since the ionic conditions prevent other side reactions from occurring, such as the self-coupling or oligomerization reactions that are observed in the case of radical trapping conditions. To demonstrate the utility of the resulting alkoxyamine initiators, end- and telechelic-alkoxyamine PEG macroinitiators derived from the alkoxyamines were synthesized by a simple chemical modification, and used for the preparation of PEG-b-PS and PS-b-PEG-b-PS block copolymers by NMRP.

• Macromolecular Research
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• 제13권5호
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• pp.391-396
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• 2005

The polymerization of methyl methacrylate (MMA) was carried out using CuBr/bidentate phosphorus ligand catalyst systems. MMA polymerization with CuBr/phosphine-phosphinidene (PP) exhibited high conversion ($\~80\%$) in 5 h at $90^{\circ}C$ along with a linear increase of ln($[M]_0/[M]$) versus time, indicating constant concentration of the propagating radicals during the polymerization. The molecular weight of the prepared PMMA tended to increase with conversion, suggesting the living polymerization characteristic of the system. On the other hand, a large difference between the measured and theoretical molecular weight and a broad molecular weight distribution were observed, implicating possible incomplete control over the polymerization. This may have been caused by the low deactivation rate constant ($\kappa_{deact}$) of the system. The low $\kappa_{deact}$, would result in irreversible generation of radicals instead of reversible activation/deactivation process of ATRP. Polymerizations performed at different ligand to CuBr ratios and different monomer to initiator ratios did not afford better control over the polymerization, suggesting that the controllability of CuBr/phosphorus ligand system for ATRP is inherently limited.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.196-197
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• 2006

Among various polymerization methods to graft polymers on the surface of CNTs, Atom Transfer Radical Polymerization (ATRP) has several advantages, such as a wide range of polymerizable monomers and superb control in molecular structure and weights. Several research groups including us have showed that ATRP is an efficient and versatile method to modify the surface of CNTs. Here, two independent approaches for the covalent attachment of polymers based on ATRP graft-from and graft-onto methods will be discussed.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.321-321
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• 2006

Aromatic diacetylenes form stable oligomeric diradicals when irradiated with UV light or heated at temperatures above their melting points. In this paper, the formation of stable diradicals is discussed, and the mechanism of polymerization in the presence of peroxide in solution, is discussed. The diphenyldiacetylene undergoes polymerization through coupling of diradicals, and not by the successive addition of radical species.

• Macromolecular Research
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• 제15권4호
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• pp.324-329
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• 2007

An octa-functional alkoxyamine initiator, with the 2,2,6,6-tetramethyl-l-piperidinyloxy (TEMPO) free radical, was synthesized based on resorcinarene, with its efficiency to initiate the nitroxide-mediated free radical copolymerization of styrene and methyl methacrylate (MMA) described. A difunctional analogue of this initiator was also synthesized, using resorcinol as the core molecule. The structures of the resulting initiators were confirmed by homolysis studies based on electron spin resonance spectroscopy and molecular modeling. The polymerization behavior and characteristics of the polymers obtained using these two initiators were also compared. Well-defined star-shaped and linear random copolymers, with low polydispersities and controlled molecular weights, were prepared. The efficiencies of these initiators towards copolymerization, as well as the parameters permitting the formation of well-defined polymers, were also investigated. The reactivity ratios were $r_a=0.42(a=styrene)\;and\;r_b=0.33(b=MMA)$ for the octa-functional initiator system and $r_a=0.45\;and\;r_b=0.39$ for the difunctional initiator system.

• Macromolecular Research
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• 제15권4호
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• pp.385-391
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• 2007

Block copolymer micelles are generally formed via the self-assembly of amphiphilic block copolymers in an aqueous medium. The hydrophilic and hydrophobic blocks form shell and core micelles, respectively. The block copolymers of methoxy poly(ethylene glycol) (MPEG)-b-poly(2-diisopropylamino)ethyl methacrylate (PDPA) were synthesized via atom transfer radical polymerization, with the macro initiator synthesized by the coupling of 2-bromoisobutyryl bromide with MPEG in the presence of a triethyl amine base catalyst. The atom transfer radical polymerization of 2-diisopropylamino)ethyl methacrylate was performed in conjunction with an N,N,N',N",N"-pentamethyl-diethylenetriamine/copper bromide catalyst system, in DMF, at $70^{\circ}C$. The pH induced micellization/demicellization was studied using fluorescence, with a pyrene probe. Furthermore, the pH dependent micellization was confirmed using the microviscosity method, with a dipyme fluorescence probe. The pH dependant micelle size distribution was studied using dynamic light scattering. The characterization of the synthesized polymers was established using gel permeation chromatography and from the $^1H-nuclear$ magnetic resonance spectroscopy.