• 대한화학회지
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• 제24권3호
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• pp.259-265
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• 1980

자유라디칼 telomerization 반응을 이용하여 스티렌-메타크릴산메틸 block 혼성중합체 (PS-b-PMMA)를 합성하였다. AIBN을 개시제로 사용하여 CCI$_4$로 스티렌을 telomerization시킨 다음 생성된 중합체의 $CCI_3$ 말단기를 macrotelogen으로 사용하여 AIBN 개시에 의해 메타크릴산 메틸을 다시 telomerization하여 스티렌-메타크릴산메틸 block 혼성중합체를 얻었다. Macrotelogen의 농도, 단위체의 농도, macrotelogen의 분자량, 반응온도 및 용매의 농도가 block 혼성중합체생성에 미치는 영향을 조사하였다. 반응조건을 조절하여, PMMA가 약 10무게%까지 포함된 block 혼성중합체를 얻었다.

• Macromolecular Research
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• 제10권6호
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• pp.339-344
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• 2002

Poly(vinyl alcohol-b-styrene) (poly(VA-b-St)) diblock copolymer containing high syndiotactic poly (vinyl alcohol) (PVA) was synthesized by the saponification of poly(vinyl pivalate-b-styrene) (poly(VPi-b-St)). For the block copolymer, poly(vinyl pivalate) (PVPi) with trichloromethyl end group was obtained via telomerization of vinyl pivalate with carbon tetrachloride as a telogen and 2,2-azobisisobutyronitrile (AIBN) as an initiator. Then resulting poly(vinyl pivalate) with trichloromethyl end group was used as an effient macroinitiator for the synthesis of poly(VPi-b-St) using atom transfer radical polymerization (ATRP) in the presence of CuCl/2,2'-bipyridine at 130 $^{\circ}C$. The poly(vinyl pivalate) macroinitiator, poly(VPi-b-St), poly(VA-b-St) were characterized by GPC, FT-IR and $^1$H-NMR. And the analysis showed that integrity of the block copolymer was maintained during saponification reaction.

• 폴리머
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• 제27권1호
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• pp.26-32
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• 2003

피발산 비닐의 라디칼 텔로머화반응을 통하여 양 말단에 관능기를 포함한 폴리(피발산 비닐) 텔로머를 합성하였다. 합성된 텔로머의 수평균분자량 ($\bar{M}$n)은 GPC, $^1$H-NMR, 점도법 세가지로 각각 고찰하였고, 그 값은 2400~13000 g/mol 이었다. 또한, 텔로머의 분자량을 정밀제어하기 위하여 VPi에 대한 텔로겐($CCl_4$)의 연쇄이동상수값($C_s$)을 Mayo식 및 시뮬레이션에 의해 결정하였는데, $C_s$은 40, 50, 60 $^{\circ}C$에서 각각 1.15, 1.16, 1.18 이었다. 합성된 텔로머는 전환율 18~72%에서 $\bar{M}$n은 5100~5400 g/mol 사이의 값을 보였고, 이는 시뮬레이션 결과와 일치하였다.

• Macromolecular Research
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• 제17권8호
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• pp.557-562
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• 2009

The free radical polymerization of styrene was initiated with azobis(isobutyronitrile) in the presence of benzene sulfonyl chloride. Analysis of the terminal structures of the obtained polystyrene with $^1H$ NMR spectroscopy revealed the presence of a phenyl sulfonyl group at the ${\alpha}$-end and a chlorine atom at the ${\omega}$-end of each polystyrene chain. The terminal chlorine atom in the polystyrene chains was further confirmed through atom transfer radical polymerization (ATRP) of styrene and methyl acrylate using the obtained polystyrenes as macroinitiators and CuCl/2,2'-bipyridine as the catalyst system. GPC traces of the products obtained in ATRP at different reaction times were clearly shifted to higher molecular weight direction, indicating that nearly all the macroinitiator chains initiated ATRP of the second monomers. In addition, the number-average molecular weights of the polystyrenes increased directly proportional to the monomer conversions, and agreed well with the theoretical ones.

• Bulletin of the Korean Chemical Society
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• 제1권2호
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• pp.45-49
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• 1980

During the homolytic reactions of $CCl_4$ or $Cl_3CBr with ${\beta}-halo^1$-styrenes,$\beta$-haloradicals are key intermediates. They are to be stabilized via three pathways; $\beta$-cleavage, halogen transfer and telomerization. The three reaction paths are delicately controlled by the energetics of their formation and stabilization. When the formation of a $\beta$-haloradical is accompanied by considerable excess of energy from an exothermic reaction, $\beta$ -cleavage is often dominant over the halogen transfer. On the other hand, if the radical forms via a reversible reaction, two processes become competitive. $\beta$-Eliminated bromine atoms from ${\beta}$ -bromoradicals generate $Br_2$ via $Cl_3CBr + {\cdot}Br {\leftrightarrow} Br_2 + {CCl_3}{\cdot}{Br_2}$ may act as a better scavenger than Cl3CBr for the ${\beta}$-bromoradicals. Different reactivities of chlorine, bromine and trichloromethyl radicals towards olefinic pi-bond are clarified in terms of the beat content of the addition reactions.