• Applied Chemistry for Engineering
• /
• v.29 no.3
• /
• pp.336-341
• /
• 2018

In general, the synthesis of poly(3-hexylthiophene)(P3HT)-based block copolymers requires at least a 4-5 step process. To control the molecular weight, molecular weight distribution, and block ratio, the reaction conversion and time should be monitored. In addition, the reaction scale usually limited to several mg to g was difficult to increase due to the limitations of living radical polymerizations. In this study, we synthesized P3HT-b-poly(4-vinylprydine) (P3HT-b-P4VP) with a final product quantity of > 19 g via a 2-step synthetic method with an anionic polymerization. In this method, the molecular weight and molecular weight distribution of P3HT-b-P4VP can be well controlled without monitoring the reaction conversion. We also studied physical properties of P3HT-b-P4VP depending on different solvent systems, which were investigated by UV-vis spectroscopy, atomic force microscopy, and ultraviolet photoelectron spectroscopy.

• Applied Chemistry for Engineering
• /
• v.8 no.3
• /
• pp.425-429
• /
• 1997

Polyisobutenylsuccinic anhydride(PIBSA), an intermediate for the lubricating oil additive, was prepared by the reaction of polyisobutylene(PIB) with maleic anhydride (MA). The functionality, which indicates the extent of reaction of PIB-a and MA, was determined in the various reaction conditions : fuctionality was 0.98 under the reaction conditions of no solvent for 12 hours at $190^{\circ}C$, 0.21 in benzyl alcohol solvent for 12 hours at $190^{\circ}C$, and 0.03~0.20 with various Lewis acids such as $AlCl_3$, $SnCl_4$, $Et_2AlCl$, and $TiCl_4$. The fuctionality also depended on the structure of PIBs. As ${\alpha}$-olefin content (exo-form) in PIB increased, the fuctionality had a higher value. The structure of PIBSA prepared from PIB and MA was determined with FT IR and $^1H$ NMR spectroscopy. Two strong anhydride IR bands at 1782 and $1855cm^{-1}$ were obserbed and two IR bands at 1639 and $897cm^{-1}$ for unsaturated groups of PIB disappeared. The presence of the anhydride was difficult to find by $^1H$ NMR spectroscopy because the anhydride protons gave relatively small peaks over a 2.0~3.0 range. Polyisobutenylsccinimide (PIBSI), a lublicating oil additive, was prepared by the reaction of PIBSA with diaminoethane.

• Applied Chemistry for Engineering
• /
• v.3 no.1
• /
• pp.130-137
• /
• 1992

The Graft copolymerization of acrylonitrile(AN) and styrene(ST) onto chloroprene rubber(CR) were carried out with benzoyl peroxide(BPO) as an initiator. The synthesized graft copolymer(ACS) was separated from polymeric mixture by the extraction with ethyl acetate and n-hexane, acetone and methanol, dimethylformamide(DMF) and methanol mixed solvent systems. The graft copolymer obtained, acrylonitrile-chloroprene-styrene(ACS) was identified by IR spectrophotometer. The effect of mole ratio of styrene to acrylonitrile, reaction time and temperature, initiator concentration, CR content and solvents on graft copolymerization were examined. It was observed that the grafting efficiency increased with [ST]/[AN] mole ratio and reaction time. The grafting efficiency increased with increasing initiator concentration and CR content. The maximum grafting efficiency was obtained when the mole ratio of [ST]/[AN] was 1.5 and reaction was made at 40hrs, and $70^{\circ}C$ using chloroform/toluene mixed solvent. The thermal properties, light resistance and flammability of ACS were compared with those of ABS and AES. It was found that flame retardancy of related polymers increased in the order ACS>ABS>AES. The thermal stability of ACS was greatly improved when compared with ABS or AES. Morphology of ACS was also investigated by using a transmisson electron microscope(TEM).

• Applied Chemistry for Engineering
• /
• v.29 no.2
• /
• pp.225-228
• /
• 2018

Plasticizers added to thermoplastic polymers are known to shorten the life of products due to the elution to outside, and some of them are harmful to our environment and human body. Since the use of phthalate plasticizers suspected of being carcinogens has been gradually prohibited, there is a need for environmentally friendly plasticizers that can replace them. Most of the substances have a low compatibility with resin, high cost and lack of safety verification. Therefore, in this study, four kinds of norbornene dialkyl ester compounds possessing excellent physical properties, which are also reported as safe compounds from the toxicity evaluation, were added to PVC resin to evaluate the possibility of human exposure by leaching, and also the potential usage as plasticizer candidates alternative to commercial ones including DEHP, DINCH and DOTP. The test was carried out according to the American standard test method (ASTM). The results showed that di-2-ethylhexyl-5-norbornene-2,3-dicarboxylate (DEHN) in aqueous solvents and diisopentyl-5-norbornene-2,3-dicarboxylate (DIPN) compounds in oil solvents were superior or equivalent to DEHP. In addition, all four norbornene compounds showed lower values than 100 ppm, which is considered to have an influence on the environment, indicating that the polar norbornene structure affects the elution.

• Journal of Applied Biological Chemistry
• /
• v.65 no.3
• /
• pp.215-219
• /
• 2022

The flowers of Cosmos bipinnatus were extracted with solvent made with methanol:water (4:1) and the concentrates were partitioned into ethyl acetate (EtOAc), n-butanol (n-BuOH), and water (H₂O) fractions. The octadecyl silica gel (ODS) and silica gel (SiO₂) column chromatographies were repeated for the EtOAc fraction to isolated of two phenolic compounds. The chemical structure of the isolated compounds were identified as benzyl O-β-ᴅ-glucopyranoside (1), and 2-phenylethyl O-β-ᴅ-glucopyranoside (2) through spectroscopic datas such as nuclear magnetic resornance, infrarad spectroscopy, and mass spectroscopy. These two compounds were first isolated from C. bipinnatus flowers through this study. To evaluate the anti-atopic activity of the two isolated compounds using a HaCaT cell line induced by ultraviolet light, several experiments were conducted and neither both compounds showed toxicity in the concentration range of 1 to 1,000 ㎍/mL. In the results of anti-atopic activity through Thymus and activation regualted chemokine (TARC) assay, both compounds showed dose-dependent TARC inhibitory activity. In particular, compound 1 showed significant activity even in a low concentration range of 10 ㎍/mL, and in different concentration ranges. Also compound 1 showed higher inhibitory activity than other compound, confirming that the anti-atopic activity was the most excellent. Based on these results, it is considered that it can be used as a functional cosmetic material.

• Journal of Applied Biological Chemistry
• /
• v.66
• /
• pp.477-483
• /
• 2023

The flowers of Carthamus tinctorius (Safflower) were extracted with 80% aqueous methanol (CTex) and the concentrates were partitioned into EtOAc (CTE), n-BuOH (CTB), and H₂O (CTW) fractions. Repeated silica gel (SiO₂) and octadecyl silica gel column chromatographies for the EtOAc and n-BuOH fractions led to isolation of four flavonol glycosides. Nuclear magnetic resornance, infrarad spectroscopy, and mass spectroscopy revealed the chemical structure of the isolated compounds, astragalin (1), isoquercetin (2), nicotiflorin (3), and rutin (4). Quantitative analysis of four isolated compounds in CTex was performed by HPLC. CTex was found to contain 1 at 0.107, 2 at 0.367, 3 at 6.752, and 4 at 0.991 mg/g, respectively. Through this study, an experiment was conducted to evaluate the protective effect on pancreatic islets of the extract, solvent fractions, and all isolated compounds using a zebrafish larvae damaged by alloxan. Pancreatic islet size treated with EtOAc (CTE), n-BuOH (CTB), and H₂O (CTW) fractions and compounds 1-4 significantly increased compared to the alloxan-induced group. These results indicate that C. tinctorius flowers and its isolated compounds are used as potential anti-diabetic agents.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.33 no.4
• /
• pp.280-287
• /
• 2000

Three antimicrobial compounds (SL-l, SL-2 and SL-3) were isolated and identified from the marine red alga, Symphyocladia latiuscula. In addition, their biological functionalities such as cytotoxicity and desmutagenic activity were investigated. From the cryophyllized S. JatiuscuJa, SL-l, SL-2 and SL-3 were purified by solvent extractions and HPLC.SL-2 was crystallized in benzene-diethyl ether solvent. On the EI-MS spectra, it was found that they had three bromines in their structure which showed typical signal strength ratios at $M^+, [M+2]^+, [M+4]^+, [M+6]^+ (13: 38: 37: 12)$. $SL-l$ was identified as 2,3,6-tribromo-4,5-dihydroxybenzyl alcohol ($C_8H_7Br_3O_3, MW=374$) by NMR and MS spectra. SL-2 was assigned as 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether ($C_8H_7Br_3O_3, MW=388$) and confirmed by X-ray crystallographic analysis. SL-3 was presumed as an isomer of SL-2. Methanol extract of the S. latiuscula showed antimicrobial activities against all strains tested (bacteria, 15 strains; yeasts, 17 strains; fungi, 4 strains), much or less. The strongest inhibition activity of the methanol extract was to the Vibrio mimicus ($50 {\mu}g/ml$) and V. vulnificus ($50 {\mu}g/ml$). The mice injected intraperitoneally with 3 mg of SL-l and 5 mg of 5L-2 showed no acute toxicity response. SL-2 showed higher desmutagenic activity than SL-l against PhIP and MeIQx.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.31 no.4
• /
• pp.516-522
• /
• 1998

An Actinomycetes strain, MSA-1, containing antimicrobial component was isolated from the black sponge, Halichondzia okadai, and was identified to a genus level by morphological and chemotaxonornic methods. The gray colored spores were oval type with smooth surface and formed flexibilis spore chains. The cell wall of this strain was type I containing D-aminopimellic acid (D-DAP) and no specific sugar was detected. Phospholipid of the cell membrane was PII type including phophoethanolamine and the major fatty acids of total lipid were branched anteiso-15 : 0, iso-16 : 0, 16 : 0 and iso-17 ; 0. From these results and other characteristics described in the Bergey's Manual, this strain was identificated as a Streptomyces sp. Meanwhile, 10mg of pale yellow colored antimicreobial component was isolated by HPLC method from the cultured Streptomyces sp. (70g of cryophillized mycellis). By crystallographyc analysis, HIRESMS and NMR assignment, the antimicrobial component produced from the strain MSA-1 was elucidated as the staurosporine (indolo[2,3-a]carbazole alkaloid).

• Applied Chemistry for Engineering
• /
• v.19 no.3
• /
• pp.299-303
• /
• 2008

A thermally cross-linkable polymer, poly[(2,5-dimethoxy-1,4-phenylenevinylene)-alt-(1,4-phenylenevinylene)] (Cross-PPV), was synthesized by the Heck coupling reaction. In order for the polymer to be cross-linkable, 20 mol% excess divinylbenzene was added. The chemical structure of Cross-PPV and thermally crosslinked Cross-PPV were confirmed by FT-IR spectroscopy. From the FT-IR, UV-Vis, and PL spectral data, thermally crosslinked Cross-PPV was insoluble in common organic solvents. The HOMO and LUMO energy level of thermally cross-linked Cross-PPV were estimated -5.11 and -2.56 eV, respectively, which were determined by the cyclic voltammetry and UV-Vis spectroscopy. From the energy level data, one can easily notice that thermally crosslinked Cross-PPV can be used for hole injection layer effectively. Bilayer structured device (ITO/crosslinked Cross-PPV/PM-PPV/Al) was fabricated using poly(1,4-phenylenevinylene-(4-dicyanomethylene-4H-pyran)-2,6-vinylene-1,4-phenylenevinylene-2,5-bis(dodecyloxy)-1,4-phenylenevinylene (PM-PPV) as the emitting layer, which have HOMO and LUMO energy levels of -5.44 eV and -3.48 eV, respectively. The bilayered device had much enhanced the maximum efficiency (0.024 cd/A) and luminescence ($45cd/m^2$) than those of a single layer device (ITO/PM-PPV/Al, 0.003 cd/A, $3cd/m^2$). The enhanced performance originated from that fact that cross-linked Cross-PPV facilitatse the hole injection to the emissive layer and the injected hole and electron from ITO and Al are recombined in emitting layer (PM-PPV) effectively.

• Applied Biological Chemistry
• /
• v.50 no.4
• /
• pp.344-347
• /
• 2007

The aerial parts of Lespedeza cuneata were collected, air-dried and extracted with 95% aqueous EtOH. Then it was successively partitioned with n-hexane, $CH_2Cl_2$, EtOAc and $H_2O$. Repeated Sephadex LH-20 column chromatography on the EtOAc- and $H_2O-soluble$ fractions gave four compounds. Their structures were elucidated as quercetin (1), kaempferol (2), desmodin (3) and homoadonivernith (4) on the basis of spectroscopic evidences such as $^{1}H-NMR$, $^{13}C-NMR$, 2D-NMR and MS spectrum. Desmodin (3) and homoadonivernith (4) have not been reported from this plant so far.