• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.999-1004
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• 2011

In this study, nanodiamod's surface have formed carboxyl, hydroxyl, amine radical for the purpose of use of nanodiamond synthesized by detonation, and then it has widely stable dispersion and slowly sedimentation in solvent. Thus nanodiamonds obtained by chemical treatment were used to analyze the structure, surface statement, particle size and sedimentation specification in solvent for method X-ray diffration(XRD), scanning electron microscope energy diffraction spectroscopy(SEM-EDS), Fourier transform infrared spectroscopy (FTIR), automic force microscope(AFM).

• Bulletin of the Korean Chemical Society
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• v.11 no.2
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• pp.154-156
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• 1990

The alternating copolymers of dihydropyran(DP)-maleic anhydride(MA), dihydrofuran(DF)-MA and DF-vinylene carbonate(VC) were prepared by free radical copolymerization of DP or DF with MA or VC. The reactivity ratios for poly(DF-VC) were found to be less than unity (0.05, 0.04) and its alternating sequences were obtained by feeding an equimolar amount of the comonomers at the onset of copolymerizations. The copolymers were hydrolyzed to give poly(TP-CE), poly(TF-CE) and poly(TF-HE), whose cytotoxicities against normal and tumor cells (3LL, B16) were measured in vitro.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.162-163
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• 2021

To prepare the waterborne silicone acrylic resin coatings, acrylic resin was prepared by a radical polymerization. Glass transition temperature(Tg) of the acrylic copolymer was fixed at 30℃ and the contents of tertiary amine monomer(DMAEMA), were varied to be 5, 10, 15 and 20 wt%, hydroxyl monomer, and carboxyl monomer were fixed 10 wt%, and 4 wt% respectively. γ-Glycidoxypropyltrimethoxysilane(GPTMS) containing epoxy group was used for curing agents. The eqivalent ratio of amine to epoxy was 1:1. The prepared coatings exhibited excellent adhesion to various substrates, and various physical properties of the coatings were satisfactory. The gloss retension and color difference were improved at low tertiary amine concentration. The coatings containing 10wt% tertiary amine concentration have especially good weather resistant properties.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.83-90
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• 2015

In this study, we investigated optimum conditions for the introduction of a lot of free radical polymerizable methacrylate groups on the multi-walled carbon nanotube (MWCNT) surface. Carboxyl groups were introduced first on MWCNT surfaces by treating with a mixture of sulfuric acid and nitric acid with ultrasonic bath for 2 hours, and oxidized MWCNTs were reacted further with thionyl chloride followed by triethylenetetramine (TETA) to introduce amino groups on the oxidized MWCNT surface, to make MWCNT-$NH_2$. To introduce free radical polymerizable methacrylate groups on the MWCNT-$NH_2$, MWCNT-$NH_2$ was reacted with 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) by Michael addition reaction. We investigated progress of modification reactions for MWCNT by fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and elemental analysis (EA). We found maximum degree of Michael addition reactions between AHM and TETA grafted on MWCNT-$NH_2$ for 10:1 mol ratio and 8 hour reaction time in our reaction conditions.

• Applied Chemistry for Engineering
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• v.5 no.5
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• pp.801-807
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• 1994

Lactose substituted styrene monomer, N-(p-vinylbenzyl)-D-lactonamide(VLA) was prepared by coupling the lactose lactone with p-vinylbenzylamine. The carboxyl group of biotin was activated with N-hydroxysuccinimide in the presence of N, N'-dicyclohexylcarbodiimide. Subsquently, biotin substituted styrene monomer, N-(p-vinylbenzyl)-biotinamide(VBA) was prepared by amidation of the activated biotin with p-vinylbenzylamine. Poly(vinylbenzylactonamide-co-vinylbenzylbiotinamide), p(VLA-co-VBA) were synthesized through radical polymerization from the synthetic monomers(VLA-VBA) by using various mole ratio. The percentages of yield were 67~71%. The copolymers were found amphlphilic which had hydrophilic lactose, hydrophobic vinylbenzyl and biotin site within the structure. IR and $^{13}C-NMR$ analysis on the monomers and copolymer were carried out.

• Polymer(Korea)
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• v.26 no.3
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• pp.293-299
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• 2002

By the reaction of m-cresol as a microbicide with acryloyl chloride m-cresyl acrylate (CA) was synthesized, and polymers with the moiety of m-cresol were prepared by the radical terpolymerization of CA -methylmethacrylate -acrylic acid. The contents of CA unit in the polymers were found to be 4.7 mol% and 10.1 mol% from their nuclear magnetic resonance spectra. The number -average molecular weights of the polymers were in the range of 12000 to 15000. Through the hydrolysis of the polymers m-cresol was released. The release rate of the microbicide increased with increasing PH of the release medium. This result can be attributed to enhanced proton dissociation of carboxyl group of the acrylic acid unit in the polymers. These polymers showed microbicidal activities for S. aureus as a positive microbe and E. coli as a negative microbe.

• Journal of the Korean Society of Safety
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• v.11 no.2
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• pp.60-66
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• 1996

In order to look into the internal structure and electrical properties of insulating Silicone rubbers added reinforcing fillers ; Silica(0-140 phr ), and to examine the behavior of charged particles, and the properties of thermally stimulated current (TSC) are investigated, respectively. From the TSC which are formed by applying the electric field of 2~5 ㎸/mm to specimen at temperature range from -150 to $270^{\circ}C$, the results arp as following. In the case of non-filled specimen, four peaks of $\delta$, $\gamma$ , $\beta$ and u are obtained at the temperature of $-120^{\circ}C$, $-60^{\circ}C$, $20^{\circ}C$ and $130^{\circ}C$, respectively and the case of filled specimen, three peaks of $\delta$, ${\alpha}_2$ and ${\alpha}_1$ are observed at the temperature of of $-120^{\circ}C$, $80^{\circ}C$ and $130^{\circ}C$, respectively. The origins of these peaks are that, the $\delta$ peak seems to the result from the contribution of side chain methyl radical, and the $\beta$ peak from the depolarization of space charge polarization owing to added imputity during during manufacturing specimens, and the $\beta$ peak from the orientation of $Si-CH_3$dipole, and the ${\alpha}_2$ near the temperature of $130^{\circ}C$ from carboxyl acid that is formed by the thermal oxidation of high temperature.

• Korean Journal of Food Science and Technology
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• v.45 no.2
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• pp.174-179
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• 2013

Three low-molecular compounds were isolated from methanol extracts of pear (Pyrus pyrifolia N. cv. Chuhwangbae) fruit peels using solvent fractionation, various types of column chromatogrphy (Diaion HP-20, Sephadex LH-20, and silica gel), and high performance liquid chromatography with an assay guided by 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity. The isolated compounds were identified as 2-carboxyl-4(1H)-quinolinone (kynurenic acid, 1) from butanol fraction, cis-p-coumaric acid (2) from ethyl acetate-acidic fraction, and vanillin (3) from the ethyl acetate-phenolic fraction, respectively. These isolated compounds were confirmed on the basis of the spectroscopic data of electrospray ionization mass spectrometry and nuclear magnetic resonance. This is the first time that compounds 1-3 were isolated and identified in pear.

• Macromolecular Research
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• v.14 no.1
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• pp.87-93
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• 2006

Copolymers composed of hyaluronic acid (HA) and poly(N-isopropylacrylamide) (PNIPAAm) were prepared to create temperature-sensitive injectable gels for use in controlled drug delivery applications. Semi-telechelic PNIPAAm, with amino groups at the end of each main chain, was synthesized by radical polymerization using 2-aminoethanethiol hydrochloride (AESH) as the chain transfer agent, and was then grafted onto the carboxyl groups of HA using carbodiimide chemistry. The result of the thermo-optical analysis revealed that the phase transition of the PNIPAAm-grafted HA solution occurred at around 30$\∼$33$^{circ}C$. As the graft yield of PNIPAAm onto the HA backbone increased, the HA-g-PNIPAAm copolymer solution exhibited sharper phase transition. The short chain PNIPAAm-grafted HA ($M_{w}$=6,100) showed a narrower temperature range for optical turbidity changes than the long chain PNIPAAm-grafted HA ($M_{w}$=13,100). PNIPAAm-grafted HA exhibited an increase in viscosity above 35$^{circ}C$, thus allowing the gels to maintain their shape for 24 h after in vivo administration. From the in vitro riboflavin release study, the HA-g-PNIPAAm gel showed a more sustained release behavior when the grafting yield of PNIPAAm onto the HA backbone was increased. In addition, BSA released from the PNIPAAm-g-HA gels showed a maximum concentration in the blood 12 h after being injected into the dorsal surface of a rabbit, followed by a sustained release profile after 60 h.

• Macromolecular Research
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• v.17 no.9
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• pp.709-713
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• 2009

The aim of this study was to develop novel intestinal specific drug delivery systems with pH sensitive swelling and drug release properties. The carboxyl group of ibuprofen was converted to a vinyl ester group by reacting ibuprofen and vinyl acetate as an acylating agent in the presence of catalyst. The glucose-6-acrylate-1, 2, 3, 4-tetraacetate (GATA) monomer was prepared under mild conditions. Cubane-1, 4-dicarboxylic acid (CDA) linked to two 2-hydroxyethyl methacrylate (HEMA) group was used as the crosslinking agent (CA). Methacrylic-type polymeric prodrugs were synthesized by the free radical copolymerization of methacrylic acid, vinyl ester derivative of ibuprofen (VIP) and GATA in the presence of cubane cross linking agent. The structure of VIP was characterized and confirmed by FTIR, $^1H$ NMR and $^{13}C$ NMR spectroscopy. The composition of the cross-linked three-dimensional polymers was determined by FTIR spectroscopy. The hydrolysis of drug polymer conjugates was carried out in cel-lophane membrane dialysis bags, and the in vitro release profiles were established separately in enzyme-free simulated gastric and intestinal fluids (SGF, pH 1 and SIF, pH 7.4). The detection of a hydrolysis solution by UV spectroscopy at selected intervals showed that the drug can be released by hydrolysis of the ester bond between the drug and polymer backbone at a low rate. Drug release studies showed that increasing the MAA content in the copolymer enhances the rate of hydrolysis in SIP. These results suggest that these polymeric prodrugs can be useful for the release of ibuprofen in controlled release systems.