• 제목/요약/키워드: soluble stability

검색결과 416건 처리시간 0.029초

전기방사를 이용한 S-keratose/Nylon 6 부직포의 제조 (Preparation of S-keratose/Nylon 6 Nonwoven Webs by Electrospinning)

  • 김진원;송경근
    • 한국염색가공학회지
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    • 제17권1호
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    • pp.38-44
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    • 2005
  • Oxidation method was used to extract S-keratose from wool. Wool was treated with performic acid and soluble fraction(S-keratose) was collected by evaporating the solvent. S-keratose and Nylon 6 were dissolved in formic acid at the ratio of 100/0, 80/20, 50/50, 20/80, and 0/100, and S-keratose/Nylon 6 web of sub-micron size was made by electro-spinning technique. SEM, EA, FT-IR, XRD, and TGA were used to characterize the properties of S-keratose/Nylon 6 solutions and electrospun fibers. As the Nylon 6 content increased, viscosity, conductivity of the electrospinning solution and the diameter of spun fiber increased. Electrospun nonwoven webs have the same S-keratose/Nylon 6 ratios of the spinning solutions. The crystalline structures of S-keratose and Nylon 6 existed separately in the electrospun webs. Thermal stability of the webs increased due to Nylon 6 content.

캄프토테신 유도체의 리포좀 제형 개발 (Development of Liposomal Formulation of A Camptothecin Derivative)

  • 심진영;김진석
    • Journal of Pharmaceutical Investigation
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    • 제31권2호
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    • pp.113-117
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    • 2001
  • CKD602, a camptothecin derivative, is a synthetic and water-soluble anticancer agent possessing of topoisomerase I inhibiting activity. DPPC and DSPE-PEG liposomal formulations entrapped with CKD602 were developed. DSPE-PEG liposome, or PEGylated liposome, encapsulating CKD602 composed of dipalmitoylphosphatidylcholine (DPPC), cholesterol and distearoyl-N-monoethoxy poly (ethyleneglycol) succinylphosphatidylethanolamine $(DSPE-PEG_{2000})$ (22:11:2) was prepared by reverse-phase evaporation method. Formed liposomes were characterized in terms of the morphology, size and encapsulation efficiency. To elucidate the in vitro stability, PEGylated liposome was incubated in human plasma, and the adsorbed proteins onto the surface of liposomes were applied to the SDS-PAGE. In vitro cytotoxicity of CKD602 encapsulated in PEGylated liposome was studied in human cervical cancer cell line (HeLa). CKD602 in PEGylated liposome was found to be 40-fold more effective $(IC_{50}=1\;nM)$ than free CKD602 $(IC_{50}=40\;nM)$ in inhibiting the growth of HeLa cells in vitro.

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Synthesis and Light-emitting Properties of Random Copolymers Composed of Phenylsilyl- and Alkoxy-Sustituted Phenylenevinylene

  • Ahn, Taek
    • Transactions on Electrical and Electronic Materials
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    • 제14권5호
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    • pp.263-267
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    • 2013
  • New random copolymers of phenylsilyl- and alkoxy-substituted phenylenevinylene, DMPS(9)-MEH(1)-PPV, DMPS(5)- MEH(5)-PPV and DMPS(1)-MEH(9)-PPV, have been synthesized by the Gilch dehydrohalogenation route, and the light-emitting properties of these polymers have been studied. The synthesized polymers were completely soluble in common organic solvents, and exhibited good thermal stability, almost up to $380^{\circ}C$. They showed UV-visible absorbance and photoluminescence (PL) in the ranges of 422-510 and 513-590 nm, respectively, according to their feed ratios. Electroluminescent devices were fabricated with these polymers as emitting layers, and ITO and Al as anode and cathode, respectively. DMPS(1)-MEH(9)-PPV, DMPS(5)-MEH(5)-PPV and DMPS(9)-MEH(1)-PPV exhibited EL emission maxima at 575 nm, 565 nm, and 541 nm, respectively.

Systematic Approaches for Blue Light-emitting Polymers by Introducing Various Naphthalene Linkages into Carbazole Containing PPV Derivatives

  • Ahn, Taek
    • Transactions on Electrical and Electronic Materials
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    • 제14권5호
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    • pp.258-262
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    • 2013
  • Poly(2,3-naphthalenevinylene-alt-N-ethylhexyl-3,6-carbazolevinylene), 2,3-PNCPV, poly(2,6-naphthalene vinylenealt- N-ethylhexyl-3,6-carbazolevinylene), 2,6-PNCPV, and poly(1,4-naphthalenevinylene-alt-N-ethylhexyl-3,6- carbazolevinylene), 1,4-PNCPV were synthesized through the Wittig polycondensation reaction. The conjugation lengths of the polymers were controlled by differently linked naphthalenes in the polymer main chain. The resulting polymers were completely soluble in common organic solvents, and exhibited good thermal stability at up to $400^{\circ}C$. The synthesized polymers showed UV-visible absorbance and photoluminescence (PL) in the ranges of 357-374 nm and 487-538 nm, respectively. The carbazole and 2,3-linked naphthalene containing 2,3-PNCPV showed a blue PL peak at 487 nm. A single-layer light-emitting diode was fabricated with an ITO/polymer/Al configuration. The electroluminescence (EL) emission of 2,3-PNCPV was shown at 483 nm.

Deactivation kinetics of C. rugosa lipase

  • 손현수;이준식
    • 한국미생물생명공학회:학술대회논문집
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    • 한국미생물생명공학회 1986년도 추계학술대회
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    • pp.523.1-523
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    • 1986
  • To extend the spectrum of enzyme utilization in the organic solvent system, C. rugosal lipase was selected as a model enzyme because its substrate is soluble to organic solvent. One of the serious disadvantages in this system was the deactivation of the lipase. The pattern of lipase deactivation was the biphasic model. The activation energies for the deactivation were 14.05${\times}$10$^4$ KJ/Kg mole in the first phase and 3.59 ${\times}$ 10$^4$ KJ/mole in the second phase. The several factors were studied for their influences on the pattern of deactivation. Iso-octane as organic solvent influenced more on the first phase than the second phase. Urea as the reagent affecting boty hydrophobic interaction and hydrogen bond of enzyme also influencea more on the first phase. And the optimum pH for the activity was not correlated to that of the stability.

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Chemical synthesis of processable conducting polyaniline derivative with free amine functional groups

  • Kar, Pradip
    • Advances in materials Research
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    • 제3권2호
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    • pp.117-128
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    • 2014
  • Processable conducting polyaniline derivative with free amine functional groups was successfully synthesized from the monomer o-phenylenediamine in aqueous hydrochloric acid medium using ammonium persulfate as an oxidative initiator. The synthesized poly(o-phenylenediamine) (PoPD) in critical condition was found to be completely soluble in common organic solvents like dimethyl sulfoxide, N,N-dimethyl formamide etc. From the intrinsic viscosity measurement, the optimum condition for the polymerization was established. The polymer was characterized by ultraviolet visible spectroscopy, Fourier transform infrared spectroscopy, proton magnetic resonance spectroscopy ($^1HNMR$) and thermogravimetric (TGA) analyses. The weight average molecular weights of the synthesized polymers were determined by the dynamic light scattering (DLS) method. From the spectroscopic analysis the structure was found to resemble that of polyaniline derivative with free amine functional groups attached to ortho/meta position in the phenyl ring. However, very little ladder unit was also present with in the polymer chain. The moderate thermal stability of the synthesized polymer could be found from the TGA analysis. The average DC conductivity of $2.8{\times}10^{-4}S/cm$ was observed for the synthesized polymer pellet after doping with hydrochloric acid.

Feasibility of Composting Combinations of Sewage Sludge, Cattle Manure, and Sawdust in a Rotary Drum Reactor

  • Nayak, Ashish Kumar;Kalamdhad, Ajay S.
    • Environmental Engineering Research
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    • 제19권1호
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    • pp.47-57
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    • 2014
  • The aim of this paper was to study the effect of five different waste combinations (C/N 15, C/N 20, C/N 25, C/N 30, and control) of sewage sludge coupled with sawdust and cattle manure in a pilot scale rotary drum reactor, during 20 days of the composting process. Our results showed that C/N 30 possesses a higher temperature regime with higher % reduction in moisture content, total organic carbon, soluble biochemical oxygen demand and chemical oxygen demand; and higher % gain in total nitrogen and phosphorus at the end of the composting period implying the total amount of biodegradable organic material is stabilized. In addition, $CO_2$ evolution and oxygen uptake rate decreased during the process, reflecting the stable behavior of the final compost. A Solvita maturity index of 8 indicated that the compost was stable and ready for usage as a soil conditioner. The results indicated that composting can be an alternate technology for the management of sewage sludge disposal.

Cyclodextrin Glucanotransferase 고생산 호알칼리성 세균의 탐색과 분비 효소의 특성 (Screening of Alkalophilic Bacillus sp. for Overproduction of Cyclodextrin Glucanotransferase and Its Enzymatic Properties)

  • 도은주;박종부;이용현
    • 한국미생물·생명공학회지
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    • 제21권2호
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    • pp.119-124
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    • 1993
  • An alkalophilic microorganism for overproduction of cyclodextrin glucanotransferase (CGTase) was newly isolated from hot-water spring soil, and identified as Bacillus firmus var. alkalophilus H609. The strain maintained stability during preservation and cultivation for the enzyme production, and produced significant amount of CGTase corresponding to the volumetric activity of 75 units/mL at 37C, initial pH of 11.2, and after 40 hours. The strain excreted several different proteins showing CGTase activity that catalyzed the formation of mainly beta-and Gamma-type cyclodextrin (ratio of 7:1) from soluble starch without accumulation of alpha-type. Other enzymatic properties were also investigated.

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Preparation of New Polyenaminonitriles Containing Cyclic and Methylene Units and Their Thermal Properties

  • Cho, Jeong-Hyun;Gong, Myoung-Seon
    • Macromolecular Research
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    • 제8권5호
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    • pp.209-214
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    • 2000
  • Polyenaminonitriles containing cycloaliphatic and aliphatic units were prepared by interfacial or solution polymerization reaction of p-bis(1-chloro-2,2-dicyanovinyl) benzene (1) with 4-aminobenzyl-amine, 1-(2-aminoethyl)piperazine, 2-(aminomethyl)pyrrolidine and 4-(aminomethyl)piperidine. The chemical structure of the polymers was confirmed through a syntheses of the model compound. The resulting polymers possessed inherent viscosities of 0.29∼0.62 dL/g and they were easily soluble in polar aprotic solvents and common organic solvents. Thermal properties of the polymers such as curability and stability were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and infrared spectroscopy. The polymers exhibited a large exotherm in DSC analyses and underwent a curing reaction around 340-370$\^{C}$ to form insoluble materials. The polymers showed 70-80% residual weight at 600 $\^{C}$ under nitrogen.

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New Organic Semiconductors for Stable, High-Performance Organic Thin-Film Transistors

  • Takimiya, Kazuo;Miyazaki, Eigo;Yamamoto, Tatsuya;Izawa, Takafumi
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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    • pp.975-978
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    • 2008
  • Novel sulfur-containing aromatic compounds were developed as stable, high-performance organic semiconductors for OTFT applications. Of them, dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) consisting of six aromatic rings gave high quality thin films by vapor deposition, which acted as a superior FET channel showing FET mobility as high as $3.0\;cm^2V^{-1}s^{-1}$. On the other hand, highly soluble 2,7-dialkyl[1]benzothieno[3,2-b][1]benzothiophenes ($C_n$-BTBTs) gave solution-processible OTFTs with FET mobility higher than $1.0\;cm^2V^{-1}s^{-1}$.

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