• Journal of Radiation Industry
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• v.7 no.2_3
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• pp.167-170
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• 2013

Lignin can be a valuable natural chemical resource. Structurally, lignin is a three-dimensional polymer made up of condensed C-C bonds and some ether linkages, most of which are not readily degraded. In this study, lignin carbonization under various electron beam pretreatment conditions was characterized through a thermogravimetric analysis (TGA), X-ray diffraction (XRD) and Raman spectroscopy. Lignin stabilization was controlled by various doses of electron beam irradiation corresponding to 50, 100, 200, 500 and 1,000 kGy; the carbonization process was performed under a nitrogen gas atmosphere at $1000^{\circ}C$ for 1 h. The TGA results showed that a 1,000 kGy lignin dose increased the residue weight from 39.96% to 45.23%, compared to non-irradiated lignin. This observation is in agreement with the XRD and Raman spectroscopy results, in which the two theta degrees and the degree of crystallization were improved by increasing the electron beam irradiation.

• Bulletin of the Korean Chemical Society
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• v.16 no.11
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• pp.1056-1059
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• 1995

The bulk photopolymerization of methyl methacrylate (MMA) with primary arylsilane (e.g., phenylsilane) and various primary alkylsilanes (e.g., benzylsilane, 3-phenoxyphenyl-1-silabutane, 3-naphthyl-1-silabutane, and 3-chlorophenyl-1-silabutane) was performed to produce poly(MMA)s containing the corresponding silyl moiety as an end group. It was found for the phenylsilane that while the polymerization yields increased and then decreased with a turning point at the molar ratio of MMA:silane=10:1 as the relative silane concentration increases, the polymer molecular weights decreased, and the TGA residue yields and the relative intensities of SiH IR stretching bands increased with increment of molar ratio of silane over MMA. The photopolymerization yield of MMA with the arylsilane was found to be higher than those with the alkylsilanes and without the silanes. Thus, the silanes seemed to significantly influence on the photopolymerization as both chain initiation and chain transfer agents.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.135-144
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• 2016

Due to the high price volatility and environmental concern of petroleum, biofuels such as bioethanol produced from lignocellulosic biomass have attracted much attention. It is also expected that the amount of lignin residue generated from pretreatment of lignocellulosic biomass will increase as the volume of cellulosic bioethanol increases. Lignin is a natural aromatic polymer and has very complex chemical structures with chemical functional groups. Chemical modification of lignin such as oxypropylation and epoxidation has also been applied to the production of value-added bioplastics such as polyurethane and polyester with enhanced thermal and mechanical properties. In addition, lignin can be used for carbon fiber production in automobile industries. This review highlights recent progresses in utilizations and chemical modifications of lignin for the production of bioplastics, resins, and carbon fiber.

• Polymer(Korea)
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• v.32 no.3
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• pp.251-255
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• 2008

This study suggested antistatic material which can increase anti-static properties and mechanical strength by mixing polystyrene for conveying electronic stuffs with metal salt and ester compound as a anti-static agent. We studied about mechanical, thermal and electrical characteristics by changing the contents of MAH of poly(styrene-co-maleic anhydride), compatibilizer. As the result of measuring residue space charge of the blends of HIPS(75)/TPU(25)/poly(styrene-co-maleic anhydride)(MAH weight ratio : 25, 32, 43.5 wt%), we could find small residue charge in the blend which MAH(25 wt%) was added and it showed the highest values in tensile strength. Additionally we found out the material to which compatibilizer was added kept better anti-static properties than one to which compatibilizer was not added. In the event we could confirm that the adding of PS-co-MAH enables two polymers were mixed well when HIPS/TPU was blended and anti-static agent made easier dissipative in the blend.

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.648-656
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• 1997

Thermal treatment of soymilk residue was carried out at 140, 150, and $160^{\circ}C$ for possible use as a raw material for dietary fiber, and some physicochemical properties of the extracts were investigated. Soluble dietary fiber(SDF) content of the extracts prepared under optimal conditions was more than 30% suggesting the conversion of insoluble dietary fiber to SDF. The main sugar components of the extracts were glucose, galactose, and arabinose. Analysis of the moelcular weight distribution by high performance size exclusion chromatography revealed that the proportion of high molecular weight fraction decreased and that of middle-sized polymer increased as the extraction temperature increased. The viscosity of aqueous solution of the extracts decreased with an increase in extraction temperature, but showed no trend as pH changed. The solubility increased with extraction temperature showing the highest at $160^{\circ}C$. The extract at $140^{\circ}C$ had the biggest calcium-binding capacity, which correlated with the changes in viscosity.

• Transactions on Electrical and Electronic Materials
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• v.16 no.2
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• pp.90-94
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• 2015

In this study, the characterizations of oxide contact hole etching are investigated with C₄F₈/O₂/Ar and CH₂F₂/C₄F₈/O₂/ Ar plasma. As the percent composition of C₄F₈ in a C₄F₈/O₂/Ar mixture increases, the amount of polymer deposited on the etched surface also increases because the C_xF_y polymer layer retards the reaction of oxygen atoms with PR. Adding CH₂F₂ into the C₄F₈/O₂/Ar plasma increases the etch rate of the oxide and the selectivity of oxide to PR. The profile of contact holes was close to 90°, and no visible residue was seen in the SEM image at a C₄F₈/(C₄F₈+O₂) ratio of 58%. The changes of chemical composition in the chamber were analyzed using optical emission spectroscopy, and the chemical reaction on the etched surface was investigated using X-ray photoelectron spectroscopy.

• Journal of Integrative Natural Science
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• v.3 no.1
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• pp.1-6
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• 2010

Bis(silyl)alkylbenzenes such as bis(1-sila-sec-butyl)benzene (1) and 2-phenyl-1,3-disilapropane (2) were synthesized in high yields by the reduction of the corresponding chlorosilanes with $LiAlH_4$ in diethyl ether. The dehydrocoupling of 1 and 2 was performed using group IV metallocene complexes generated in situ from $Cp_2MCl_2$/Red-Al and $Cp_2MCl_2$/n-BuLi (M = Ti, Hf), producing two phases of polymers. The TGA residue yields of the insoluble polymers were in the range of 64-74%. The molecular weights of the soluble polymers produced ranged from 700 to 5000 ($M_w$ vs polystyrene using GPC) and from 500 to 900 ($M_w$ vs polystyrene using GPC). The dehydropolymerization of 1 and 2 seemed to initially produce a low-molecular-weight polymer, which then underwent an extensive cross-linking reaction of backbone Si-H bonds, leading to an insoluble network polymer.

• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1173-1178
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• 2008

A simple and sensitive high-performance liquid chromatographic method was developed for the simultaneous identification of enrofloxacin and its active metabolite ciprofloxacin in chicken muscle. Norflorxacin imprinted polymers synthesized in water-containing systems show high selectivity to enrofloxacin and ciprofloxacin in an aqueous environment. Using these water-compatible imprinted polymers as selective adsorbents in the solid-phase extraction of enrofloxacin and ciprofloxacin from chicken samples, the remaining biological matrix could be quickly washed out from the imprinted column while enrofloxacin and ciprofloxacin were selectively retained and enriched. Analytical separation was performed on a $C_{18}$ column using acetonitrile-water as a mobile phase and fluorescence detection. Good linearity was obtained from 0.8 to 500 ng/g (r > 0.998) with relative standard deviation of less than 3.9%. The mean recoveries of enrofloxacin and ciprofloxacin from chicken muscle were 80.6-94.5% and 77.8-91.8% at three different concentrations. The limits of determinations based on S/N=3 were 0.07 ng/g and 0.09 ng/g, which are below the maximum residue limits established in many countries.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.3
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• pp.385-392
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• 2000

The adsorption ability of dyes on chitin, a natural polymer was investigated for decolorization of dye wastewater. Chitin was manufactured in lab by decalcification in dilute aqueous HCI solution and deproteination in dilute aqueous NaOH solution with shrimp shells. Absorbance of residue solution of dyebaths after dye adsorptions of chitin were measured in varieties of dye concentration and dipping periods. Four kinds of dyestuffs were used, C.I.Acid Blue 29. C.I.Direct Blue 6, C.I.Reactive Orange 12 and C.I.Basic Red 18. When chtin 1g was dipped in 0.05% of dyebath with stirring, maximum adsorption ratio of each kind of dyes was exhibited as 91.6% for C.I.Acid Blue 29, 95% for C.I.Direct Blue 6, 58.2% for C.I.Reactive Orange 13 and 75.8% for C.I.Basic Red 19. It shows that chitin has better adsorption abilities of ionic dyes of acid, direct and basic dye than non-ionic reactive dye. And chitin has better adsorption abilities of anionic acid direct dyes than cationic basic dye because of the presence of nitrogen atoms. All kinds of dyestuffs used showed speedy absorption effects by chitin, so chitin can absorb much amount of dyes in 5 mimutes reach to equilibrium of adsorption in 2 hours after dipping. Basic dye was absorbed the most speedily in 5 minutes, although maximum adsorption ratio is not high. That reason can be thought that chitin surface is essentially negatively charged due to polar funtional groups.

• Journal of Integrative Natural Science
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• v.2 no.1
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• pp.1-12
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• 2009

This miniaccount presents the selective examples of our recent discoveries in the photopolymerization of vinyl monomers using the organic initiators such as hydrosilanes, poly(hydroarylsilane)s, benzoin silyl ethers, and thianthrene cation radical. In the photopolymerization of vinyl monomers with silanes polysilanes, while the polymerization yields and polymer molecular weights of the poly(MMA)s containing the silyl moieties decreased, the TGA residue yields and intensities of SiH stretching IR bands increased as the mole ratio of the silanes over MMA increased. The hydroarylsilane and poly(hydroarylsilane) seemed to influence strongly on the photopolymerizaiton of olefinic monomers as both chain initiation and chain transfer agents. For the photohomopolymerization and photocopolymerization of MA and AA, the similar trends were observed. Benzoin silyl ethers and thianthrene cation radical also exhibit the photoinitiating ability in the photopolymerization of MMA.