• Macromolecular Research
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• v.16 no.2
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• pp.155-162
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• 2008

We report the successful synthesis of poly(NBECOOH-b-NBEPOSS) copolymers, taking advantage of the sequential, living ring opening metathesis polymerization of NBETMS and NBEPOSS using the $RuCl_2(=CHPh)(PCY_3)_2$/$CH_2Cl_2$/$20^{\circ}C$ system, followed by the hydrolysis of trimethylsilyl groups in poly(NBETMS-b-NBEPOSS) copolymers. The living behavior of ROMP of NBETMS was first investigated using two diagnostic plots, a first order kinetic plot and a $\bar{M}_n$ vs. conversion plot. The plots confirmed that no termination and chain transfer reaction had occurred during polymerization. Poly(NBECOOH-b-NBEPOSS) copolymers were prepared using the sequential monomer addition of NBEPOSS to living poly(NBETMS) chain ends, followed by the hydrolysis of trimethylsilyl groups in the poly(NBETMS-b-NBEPOSS) copolymers. The high structural integrity of poly(NBE-COOH-b-NBEPOSS) copolymers was confirmed by $^1H$-NMR, $^{13}C$-NMR spcctroscopy and GPC.

• Polymer(Korea)
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• v.35 no.4
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• pp.308-313
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• 2011

The ring-opening isomerization polymerization behavior of 2,5,6,7-tetrahydro-3H-imidazo[2,1-b] [1,3] oxazine(TII) has been studied under various conditions. The present study aimed at improving the low polymerizability of the above monomer (six-membered ring) up to a level comparable to that of 2,5,6-tetrahydroimidazo[2,1-b] [l,3] oxazole(TIO) (five-membered ring). The optimum result could be observed when methyl trifluoromethanesulfonate(MeOTf) and nitrobenzene were used as an initiator and a solvent in the polymerization at $60^{\circ}C$ for 24 h. Polymers were confirmed by$^1H$ NMR과$^{13}C$ NMR, and m measurements. The molecular weight obtained by gel permeation chromatography (GPC) corresponded to the molecular weight theoretically calculated from the feed ratio. The melting temperature ($T_m$) of TII was conspicuously different from that of TIO, because of the difference in the alkyl group.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.200-200
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• 2006

Several polynorbornene or poly(norbornene-7-oxide) based functional block copolymers were synthesized by ring opening metathesis polymerization (ROMP) with good molecular weight and polydispersity control. Some representative functional groups in these polymers are a nitrobenzoyl group or ferrocene. These polymers were subjected to various chemical modification reactions to give other block copolymers that contain novel functionality such as amine, diazonium salt, and diazo groups. The resulting polymers were characterized by various techniques such as GPC, NMR, UV-VIS, AFM, and cyclovotammography (CV).

• Journal of the Korean Society of Industry Convergence
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• v.4 no.3
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• pp.253-255
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• 2001

기능성고분자재료 중의 하나인 7원환 고리아세탈 화합물인 1,3-dioxepan-2-one(1)을 합성하고 고온조건 하에서 중합반응을 조사한 결과 선택적인 개환중합이 일어났다. 그러나 낮은 농도에서 작은 분자량을 가지는 고분자가 얻어졌으며 넓은 분자량 분포와 낮은 수율이 얻어지며 이것은 중압반응 도중에 분자 내에서 상호반응을 일으킴을 보여준다.

• Macromolecular Research
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• v.14 no.4
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• pp.424-429
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• 2006

The synthesis of a series of poly(POSS-NBE-b-MTD) copolymers was successfully accomplished, taking advantage of sequential, ring-opening, metathesis block copolymerization using $RuCl_2(=CHPh)(PCy_3)_2$ catalyst. By using cyclopentyl-POSS-norbornene (POSS-NBE) monomer as the first block in the block copolymer, living poly(POSS-NBE) with controlled molecular weight and narrow molecular weight distribution was produced. Then, poly(POSS-NBE-b-MTD) copolymers were successfully prepared, in which sequential monomer addition of methyltetracyclododecene (MTD) to the living poly(POSS-NBE) chain ends was utilized to achieve quantitative crossover efficiency. Characterization by $^1H$ NMR spectroscopy and GPC confirmed the high definition and structural integrity of the poly(PO$S-NBE-b-MTD) copolymers. Thermal properties-and morphologies of the POSS-containing block copolymer nanocomposites were also investigated by using thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and wide-angle X-ray scattering (WAXS).

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.199-199
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• 2006

Microwave-irradiation has become a common heat source in organic chemistry in the last decade. In recent years, polymer chemists also discovered the advances of microwave heating that include fast and efficient heating as well as the homogeneous heat profile and the easy access to pressurized reaction conditions. In this contribution, we report our investigations on the cationic ring-opening polymerization of 2-oxazolines that lead to a tremendous acceleration from several days to several minutes polymerization time. In addition, the optimized microwave-assisted polymerization procedure was applied for the preparation of libraries of diblock and triblock copolymers that were used for the determination of structure-property relationships in poly(2-oxazoline)s.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4122-4126
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• 2012

Cellulose-graft-poly (L-lactide) (cellulose-g-PLLA) was successfully prepared via ring-opening polymerization (ROP) by using 4-dimethylaminopyridine (DMAP) as an organic catalyst in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). The structure and morphology of the polymer was characterized by nuclear magnetic resonance (NMR) and transmission electron microscope (TEM). From wide-angle X-ray powder diffraction (WAXD) and degradation test (by acid, alkaline, PBS and enzyme solution), changes in the crystalline structure as a result of degradation was also investigated. The results indicated that materials which have low degree of crystallinity showing higher degradability, however, in acid liquor, enzyme solution, alkaline liquor and PBS system, the degradation rate of the polymer decreased by the above sequence. Moreover, with the further increase of graft degree of this material, its degradation degree decreased.

• Bulletin of the Korean Chemical Society
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• v.20 no.12
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• pp.1433-1436
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• 1999

The 2-(2,4-dimethoxyphenyl)-4-MDO (2) underwent polymerization with ring opening as well as cyclization reaction in the presence of various cationic catalysts such as boron trifluoride, trifluoromethanesulfonic acid, p-toluenesulfonic acid, hydrochloric acid and trifluoroacetic acid. They afforded a mixture of the ring-opened poly(keto ether) and 3(2H)-dihydrofuranone derivative. Both the methylene group and oxygen atom of 1,3-dioxolane ring were participated in the reaction with cationic catalyst. The contents of the polymer and cyclization product were variable according to the acid strength of the cationic catalysts.

• Applied Chemistry for Engineering
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• v.2 no.1
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• pp.64-69
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• 1991

A lipid containing a 1, 2-dithiolane group was synthesized, and polymerized vesicle was prepared from the vesicle of this lipid by ring-opening polymerization. Reaction rate of the polymerization was monitored by UV absorption, and the results showed that it followed the first order kinetics and the rate constant $3.84{\times}10^{-2}min^{-1}$. Permeation rate of sucrose through the polymerized vesicle was $4.7{\times}10^{-8}cm\;hr^{-1}$, which is 1.5 times lower than that of monomeric analog.

• Bulletin of the Korean Chemical Society
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• v.7 no.3
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• pp.210-213
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• 1986

1,1-Dicyano-2-ethoxycyclobutane (1a) was prepared by [2 + 2] cycloaddition reaction of vinylidene cyanide with ethyl vinyl ether. 1,1-Dicyano-2-phenylcyclobutane (1b) was prepared by the reactions involving the reduction of cinnamyl alcohol, chlorination, cyanomethylation, bromination, and ring-closure reaction. Compound 1a was ring-opening polymerized with NaCN or n-butyllithium to give a low molecular weight polymer. The compound 1b however, failed to polymerize by either anionic or radical catalysts.