• Polymer(Korea)
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• v.30 no.4
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• pp.357-361
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• 2006

Alpha-lipoic acid (ALA) synthesized in the body has virtues such as anti-oxidation, blood sugar regulation, appetite suppression, and anti-obesity, etc. ALA, which is also used as a drug, has a five-membered ring including disulfide and so easily losses bioavailability due to ring opening and subsequent polymerization by heat or ultraviolet. This report studies various conditions for ring opening polymerization. The ring opening starts above the melting point of ALA, but there was no temperature dependence above it. At $70^{\circ}C$, the degree of ring opening was proportional to reaction time and inversely proportional concentration. The degree of ring opening in acetic acid with UV for 1 hour reached the maximum conversion (70%). Most cleaved ALA changed into disulfide polymers, and the molecular weight of the polymers increased as the amount of ring opening increased.

• Journal of the Korean Chemical Society
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• v.32 no.2
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• pp.103-112
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• 1988

For two possible paths of thermal ring opening reactions, the approximate reaction path functions, their norms and the approximate reaction path average energies are computed and compared. Illustrated examples clearly justify the postulate that the path with larger norm and lower average energy has lower barrier height than the other.

• 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.

• Bulletin of the Korean Chemical Society
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• v.26 no.10
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• pp.1617-1619
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• 2005

• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1377-1378
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• 2002

• Bulletin of the Korean Chemical Society
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• v.20 no.12
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• pp.1384-1386
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• 1999

• Composites Research
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• v.32 no.6
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• pp.375-381
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• 2019

Multiwalled carbon nanotubes (MWCNTs) are covalently functionalized with isocyanates by directly reacting commercial hydroxyl functionalized MWCNTs with excess 4,4'-methylenebis (phenyl isocyanate) (MDI) and hexamethylene diiosocyanate (HDI). HDI-modified MWCNTs results in a higher surface isocyanate density than MDI-modified MWCNTs. Anionic ring-opening polymerization of ε-caprolactam is conducted using a sodium caprolactam initiator in combination with a di-functional hexamethylene-1,6-dicarbamoylcaprolactam activator in the presence of isocyanate functionalized MWCNTs. This polymerization proceeds in a highly efficient manner at relatively low reaction temperature (150℃) and short reaction times (10 min). During the polymerization, the isocyanate functionalized MWCNTs act not only as reinforcing fillers but also as second activators. Nanocomposites with HDI modified MWCNTs exhibit higher reinforcement and faster isothermal crystallization than MDI modified MWCNTs. The results show that PA6 chains grow more effectively from HDI modified MWCNT surface than from MDI modified MWCNT surface, resulting in stronger interaction between PA6 and MWCNTs.

• Journal of Integrative Natural Science
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• v.2 no.2
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• pp.78-81
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• 2009

In recent years, organometallic polymer containing silane and silole unit has been a topic of interest because of the wide range of optical, electrical and luminescent properties. In previous work, we synthesized functionalsilanebridged[1]ferrocenophane from the reaction of dimethyldichlorosilane[Me2SiCl2] and diphenyldichlorosilane[Ph2SiCl2] and dichloromethylvinylsilane[C3H6SiCl2] with ferrocene$[Fe({\eta}-C5H4)2]$ and n-BuLi. In this work, we have synthesized Poly(ferrocenylsilane) via the Thermal Ring-Opening Polymerization(ROP). characteristics of the poly(ferrocenylsilane) were investigated by gel permeation chromatography(GPC), 1H- and 13C-NMR spectroscopy.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2573-2576
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• 2014

• Applied Chemistry for Engineering
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• v.31 no.3
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• pp.267-276
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• 2020

Poly(epichlorohydrin) copolyol series (PECH copolyols) were synthesized via cationic ring-opening copolymerization (ROCP) of oxirane-based monomers and effects of reaction temperature, solvent type, and initiator were studied. As a comonomer, two types of alkylene oxides were used, and polymerization conditions were conducted both with diethylene glycol (DEG) as an initiator in methylene chloride (MC) solvent and tripropylene glycol (TPG) in toluene solvent. In order to induce the active monomer (AM) mechanism in the ring-opening copolymerization reaction, the monomer was injected by an incremental monomer addition (IMA) method using a syringe pump, and the polymerization was performed at -5 ℃. PECH copolyol, a synthesized ephichorohydrin (ECH)-based copolyol, was converted to glycidyl azide-based energy-containing copolyol (GAP copolyol) by azadizing the ECH unit through a substitution reaction. It was confirmed that the synthesized azide copolyol had little effects on changes of the solvent and the initiator. Also, the molecular weight increased 500 after the azide reaction, thereby the GAP copolyol was polymerized as designed. As the content of the comonomer increased, both the T_g and viscosity tended to decrease due to the influence of the alkyl chain length. It is possible to fundamentally prevent CH₃N₃ amount produced in the azide reaction process, and it is expected that a large-scale process could be achievable.