• Macromolecular Research
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• v.10 no.3
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• pp.168-173
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• 2002

Unstabilized low-density polyethylene (LDPE) films and films formulated with hindered amine light stabilizer (HALS) were exposed to UV-radiation; and the physicochemical changes during photooxidation processes have been investigated using tensile, FTIR spectre-photometric and thermal analytical (DSC) techniques. The dependence of tensile properties (elongation- and stress-at-break), carboxyl index and heat of fusion on UV-irradiation time have been discussed. The use of HALS is found to be effective in maintaining the UV-mechanical properties of the LDPE films. The experimental results showed that there exists no correlation between mechanical properties and carbonyl index, whereas crystallinity correlates well with carbonyl index in unstabilized and stabilized films for irradiation times greater than 100 h. The rate of formation of carbonyl groups is found to be dependent on UV exposure time. Crystallinity of the film samples is strongly influenced by both exposure time and presence of HALS.

• Carbon letters
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• v.13 no.1
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• pp.29-33
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• 2012

A novel strategy for the simultaneous reduction and functionalization of graphene oxide (G-O) was developed using polyallylamine hydrochloride (PAAH) as a multi-functional agent. The G-O functionalization by PAAH was carried out under basic conditions to catalyze the epoxide ring opening reaction of G-O with abundant amine groups of PAAH. We found that G-O was not only functionalized with PAAH but also reduced under the reaction condition. Moreover, the synthesized PAAH-functionalized G-O sheets were soluble in water and applicable to the synthesis of nanocomposites with gold nanoparticles.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.149-153
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• 2013

The chemical functionalization of carboxylated multi-walled carbon nanotubes (MWCNT-COOH) by creatinine (MWCNT-Amide) and latter modification with 2-aminobenzophenone for producing 1-methyl-9-phenyl-1H-imidazo[4,5-b]quinolin-2-amine (MWCNT-quino) have been investigated. All products were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscope, elemental analysis, thermogravimetric analysis, derivative thermogravimetric and cellular investigations. The interesting point is that MWCNT-quino can be homogeneously dispersed in dimethylformamide and to some extent in ethyl alcohol without sonication. Also, MTT assay was used to examine the behavior of cell proliferation after 48 h of cell culture experiments. Cellular results showed high toxicity of MWCNT-quino on the cancer cells. These functionalizations have been chosen due to active sites of carbonyl and methylene groups in MWCNT-Amide and the creating quinoline derivative on the MWCNTs for future application.

• Bulletin of the Korean Chemical Society
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• v.24 no.11
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• pp.1637-1640
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• 2003

Quaternary ammonium groups were introduced to Starburst polyamidoamine (PAMAM) dendrimers for a gene carrier. These quaternary dendritic carriers exhibited reduced cytotoxicity on 293T cells compared to parent dendrimers examined and their transfection efficiency were similar with parent dendrimers. Quaternization could be a promising tool to improve properties of dendrimers as a gene delivery carrier.

• KSTLE International Journal
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• v.8 no.2
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• pp.21-25
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• 2007

The electrorheological effect of the suspension composed of Bismark Brown chitosan succinate as the dispersed phase in silicone oil was investigated. Bismark Brown chitosan succinate suspension showed a typical ER response (Bingham flow behavior) upon application of an electric field. The shear stress for the suspension exhibited the dependence with a factor equals to 1.84 power on the electric field. The experimental results for the suspension correlated with the polarization model and Bismark Brown chitosan succinate suspension behaved as an anhydrous ER fluid. On the basis of the results, Bismark Brown chitosan succinate suspension showed the ER flow behavior upon application of the electric field due to the polarizability of the branched amide and amine polar groups of the Bismark brown chitosan succinate particles.

• Bulletin of the Korean Chemical Society
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• v.17 no.5
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• pp.433-436
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• 1996

Cobalt(Ⅲ) complexes of trifunctional amino acid and N,N'-diethylethylenediamine-N,N'-di-α-butyrate(deedba), s-cis-[Co(deedba)(L-aa)] (L-aa=S-methyl-L-cysteine, L-aspartic acid, L-glutamic acid) have been prepared from the reaction between the s-cis-[Co(deedba)(Cl2)]- complex and the corresponding amino acid. The amino acids have been found to coordinate through the amine and carboxylate groups. The S-methyl-L-cystene is coordinated not by the sulfur donor atom, but by the nitrogen and oxgen donor atoms, and the L-aspartic and L-glutamic acids are coordinated to the cobalt(Ⅲ) ion via formation of the five-membered glycinate chelate ring. Relatively small optical activity shown by the complexes is due to the chiral center present in the amino acids.

• Archives of Pharmacal Research
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• v.23 no.3
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• pp.202-205
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• 2000

A convenient pathway for synthesis of trans-metanicotine analogues was developed. trans-Metanicotine, a subtype(${\alpha}4{\beta}2$)-selective ligand for neuronal nicotinic acetylcholine receptor, is under clinical phase for Alzheimer's disease. Zn-mediated allylation of allyl bromide and acetaldehyde followed by Heck reaction with 3-bromopyridine gave 5-pyridin-3-yl-pent-4-en-3-ol (2). Tosylation of 5-pyridin-3-yl-pent-4-en-3-ol followed by substitution reaction with methylamine in sealed tube gave methyl-(1-methyl-4-pyridin-3-yl-but-3-enyl)-amine (4) in good yields. Thus, trans-metanicotine analogues modified at the $\alpha$-position of the methylamino group with various functional groups can be obtained in 4 steps.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.197-201
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• 1998

The complex formation from Cu(Ⅱ) ion and 1,3-bis(tris(hydroxymethyl)methylamino)propane (bistrispropane) in aqueous solution has been studied potentiometrically and spectrophotometrically. Bistrispropane (btp) coordinates to Cu(Ⅱ) as multidentate. In the btp (L) complex CuL2+, two of the hydroxyl oxygen atoms as well as the amine nitrogens of the ligand are coordinated. In neutral and weakly acidic media, one of the coordinated hydroxyl groups is deprotonated. In basic media, an additional hydroxyl group undergoes deprotonation. The equilibrium constants for the formation of CuL2+, CuLH-1+, and CuLH-2 have been determined. The nature of the coordinate bonds has been deduced from the potentiometric data and the spectra of these complexes.

• Journal of the Korean Magnetic Resonance Society
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• v.26 no.4
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• pp.40-45
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• 2022

A small cage-like molecule (2) composed of three aminomethyl pyrroles and two hexa-substituted benzenes has been prepared by reduction of its iminopyrrole analogue (1) using NaBH₄. It was revealed by ¹H NMR spectroscopic analyses that cage molecule 2 strongly binds the fluoride anion in polar DMSO-d₆ relative to CDCl₃. Compared to that of compound 1, the lowered affinity of 2 for the fluoride anion is attributable to its increased electron density resulting from the production of thesecondary amine groups.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.255-256
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• 2022

We synthesized catechol-conjugated chitosan (CCC) to study its usefulness as a construction material additive in cement mortar. The degree of catechol conju-gation (DOC_cat) of the synthesized CCC was determined to be approximately14% by UV-vis and ¹H NMR spectroscopy. Furthermore, the hydroxyl and amine groups in CCC could play a crucial role in hydrogen bonding, metal coordination, and cross-linking processes via interaction with adducts from cement mortar. In this study, we observedanimprovement in the compressive strength and absorption rate, suggesting that CCC is a promising candidateforhigh-performance cement mortar.