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  • Polymer and Materials Science  (7)
  • Enantiomer separation  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Enantiomeric separation of trimetoquinol, denopamine and timepidium by capillary electrophoresis and HPLC and the application of capillary electrophoresis to the optical purity testing of the drugs (1995)
    Springer
    Chromatographia 40 (1995), S. 638-644 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Capillary electrophoresis ; Enantiomer separation ; Trimetoquinol ; Denopamine ; Timepidium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Two methods for the direct separation of the enantiomers of trimetoquinol hydrochloride, denopamine and timepidium bromide were investigated, namely capillary zone electrophoresis (CZE) using cyclodextrins (CDs) (CD-CZE) and high-performance liquid chromatography (HPLC) using chiral stationary phases (CSPs). By CZE, separation of the enantiomers of trimetoquinol was successfully achieved when using β-cyclodextrin (β-CD), heptakis(2,6-di-0-methyl)-β-cyclodextrin (DM-β-CD) and β-CD polymer, but direct HPLC separation of the enantiomers was not successful. The enantiomers of denopamine were successfully separated by both CZE, employing DM-β-CD under acidic conditions, and HPLC, with cyclodextrin immobilized CSPs (CD-CSPs). Timepidium bromide, which is a racemic drug, was successfully enantioseparated by both CD-CZE and HPLC with CD-CSPs. The CD-CZE mode was selected as the optical purity testing method for trimetoquinol and denopamine because of the superiority of capillary electrophoretic (CE) techniques. Method validation results obtained clearly show that the CE method would be useful as an quality control method for assessing the optical purity of the drugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02315130
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  • 2
    Electronic Resource
    Electronic Resource
    Enantiomer separation by capillary electrophoresis using DEAE-dextran and aminoglycosidic antibiotics (1996)
    Springer
    Chromatographia 43 (1996), S. 426-430 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; Aminoglycosidic antibiotics ; DEAE-dextran ; Drugs ; Enantiomer separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Diethylaminoethyl (DEAE) dextran hydrochloride and three kinds of aminoglycosidic antibiotics; fradiomycin sulfate, kanamycin sulfate and streptomycin sulfate, were employed as chiral selectors in capillary electrophoresis, enantiomer separation. These selectors are cationic or basic because of amino functionality and therefore used for enantiomer separation of acidic compounds. To avoid adsorption of the basic or cationic selectors on the capillary inner surface, a coated capillary was employed. Among those tested, enantiomers of binaphthyl compounds and synthetic intermediates of diltiazem analogues were separated. Methanol addition was effective for the improvement of peak shape and resolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02271023
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  • 3
    Electronic Resource
    Electronic Resource
    Fluorine-containing optical adhesives for optical communications systems (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 2141-2148 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Fluroinated epoxy resin adhesives containing diglycidylether of bisphenol AF (DGEBAF) with a fluorine content of 25.7 wt % are developed for fabrication of optical communications devices. These adhesives, formulated with a diluent of butanediol diglycidylether (BDDG) and a curing agent of polyether polyamine (Q694), can be cured at a curing temperature as low as 65°C and exhibit high transparency of more than 80% in the wavelength range of 0.5-1.3 μm. Moreover, they significantly reduce return loss at optical-glass/adhesive interfaces because of the low refractive indices of ca. 1.52 and also improve heat durability of optical devices. They are successfully applied to submarine optical fiber transmission system.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070420804
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  • 4
    Electronic Resource
    Electronic Resource
    Thermal properties of solvolysis lignin-derived polyurethanes (1992)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 3 (1992), S. 151-155 
    Details
    ISSN: 1042-7147
    Keywords: Polyurethane ; Solvolysis lignin ; Crosslinking ; Thermogravimetry ; Decomposition ; DSC ; Glass transition ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Thermal properties of polyurethane (PU) films prepared from solvolysis lignin (SL), polyethylene glycol (PEG) and diphenylmethane diisocyanate (MDI) were examined by differential scanning calorimetry and thermogravimetry. In the SL - PEG - MDI system, the SL content, the molecular weight (Mn) of PEG and the NCO/OH ratio were changed in order to control the thermal properties. Glass transition temperatures (Tg's) of the prepared PU's were dependent on the SL content, the Mn of PEG and the NCO/OH ratio. However, the Tg of PU was significantly influenced by the SL content: the increment of Tg was ca. 150 K when the SL content in PEG increased from 0 to ca. 50%. The decomposition of the PU's was markedly dependent on the content of SL. Other factors, such as the NCO/OH ratio and the Mn of PEG, are less dominant compared with the SL content. This fact suggests that the dissociation between the isocyanate groups and the phenolic OH groups in SL may be the major factor in the whole process of the thermal decomposition of the PU containing SL
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1992.220030402
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  • 5
    Electronic Resource
    Electronic Resource
    Some aspects of nonisothermal crystallization of polymers. III. Crystallization during melt spinning (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 615-623 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Crystallization during melt spinning is studied as an example of the nonisothermal crystallization of polymers. The following equation is derived, taking the temperature distribution within a filament into consideration: \documentclass{article}\pagestyle{empty}\begin{document}$$ \kappa \nabla ^2 T = {\rm V} \cdot {\rm grad } \ T - \frac{{\Delta H}}{{C_p }}{\rm V} \cdot {\rm grad } \ X $$\end{document} where T = temperature, X = crystallinity, κ = thermal diffusivity, V = velocity, ΔH = heat of crystallization, and Cp = specific heat at constant pressure. The assumptions and the procedure for a numerical calculation of crystallinity and temperature within a running filament are described, and some results of calculation are illustrated. The results are compared with those obtained by a simpler calculation in which the radial temperature distribution is neglected. The simpler method proved useful in connection with x-ray measurements.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180223
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  • 6
    Electronic Resource
    Electronic Resource
    Some aspects of nonisothermal crystallization of polymers. I. Relationship between crystallization temperature, crystallinity, and cooling conditions (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 1077-1091 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The changes in temperature and crystallinity of polymer during nonisothermal crystallization were theoretically analyzed assuming a cooling condition under which heat transfer occurs at a rate proportional to the difference in temperature between polymer and the environment. When a plateau appears in the temperature change during crystallization, crystallization temperature can be predicted by a simple method. This method gives nearly the same value as that obtained by successive calculations of temperature and crystallinity throughout the whole process. In addition, a graphic method is presented to predict crystallization temperature. By using the plateau temperature observed in melt-spinning experiments, the crystallization rate under molecular orientation is evaluated. Furthermore, a method applicable to estimating the ultimate crystallinity is proposed. A rough estimation of the increase in the rate of crystallization under molecular orientation was carried out for very high-speed spinning of poly(ethylene terephthalate).
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160503
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  • 7
    Electronic Resource
    Electronic Resource
    Some aspects of nonisothermal crystallization of polymers. II. Consideration of the isokinetic condition (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 1031-1041 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In the previous paper a practical method has been applied for an analysis of non-isothermal crystallization in terms of data of isothermal crystallization. The fundamental equation was written on the assumption of the isokinetic conditions in the following form: \documentclass{article}\pagestyle{empty}\begin{document}$ X\left( {\rm t} \right) = 1 - \exp \left[ { - \left( {\int_0^t {K\left( T \right)d\tau } } \right)^n } \right] $\end{document} where X(t) is the degree of phase transformation at time t, and n is the Avrami index determined in the isothermal experiments; K(T) is connected with the crystallization rate constant of the isothermal crystallization, k(T), through the relation K(T) = k(T)1/n. The equation is derived on the basis of the well-known theory of phase transformation. Experiments of nonisothermal crystallization of high-density polyethylene were carried out under various cooling conditions. The change in crystallinity during the process was followed by using the above equation in the course of the primary crystallization. A procedure of the analysis of the whole, including both the primary and secondary processes, is suggested as an eminently practical one on a more general assumption.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1973.070170404
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  • 8
    Electronic Resource
    Electronic Resource
    Strain criterion in nonlinear creep and recovery in concentrated polymer solutions (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 22 (1984), S. 1119-1148 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Transient and steady-state rheological data are reported for several anionic polystyrene solutions in tritolylphosphate (1. 6 〈 cM/ρMc 〈 7). Here c is the concentration of the solution, M is the molecular weight, ρ the density of the undiluted polymer, and Mc the molecular weight between entanglements as determined from zero-shear viscosity. The polystyrene used had Mw = 410,000 and Mw/Mn 〈 1.06. Data are also given for solutions of polyisobutylene and poly(vinyl acetate) with larger Mw/Mn. The results give a critical strain γ′ ∝ c-1 such that linear viscoelastic behavior was obtained in a simple shear deformation with shear less than γ′. A simplified version of the constitutive equation of Bernstein, Kearsley, and Zapas is used with an empirical strain function F (γ) which contains γ′ as a parameter to discuss transient and steady-state behavior in terms of the distribution of relaxation (or retardation) times determined for linear viscoelastic responce. Features of the dependence of the steady-state viscosity ηk, recoverable compliance Rk, the first-normal stress function Nk(1) on shear rate k are discussed in terms of F (γ) and the distribution of relaxation times to conclude that the latter plays a dominant role in the behavior observed in the range of k usually studied. The results predict that the reduced functions ηk/η0, Rk/R0, and Nk(1)/N0(1) should depend on η0R0k, and that the functional form depends markedly on the distribution of relaxation times, at least in the range η0R0k 〈 102. Comparison with the mechanistic model of Doi and Edwards shows a similar F (γ) but substantial differences in the reduced functions caused by a very narrow distribution of relaxation times in the model.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.180220614
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  • 9
    Electronic Resource
    Electronic Resource
    Syntheses and properties of cured epoxy resins containing the perfluorobutenyloxy group. I. Epoxy resin cured with perfluorobutenyloxyphthalic anhydride (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 831-840 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Perfluorobutenyloxyphthalic anhydride (PFPA) has been synthesized as a new curing agent for epoxy resins, and the properties of epoxy resin cured with PFPA have been investigated. Good PFPA synthesis yields were realized by a dehydrating ring closure of perfluorobutenyloxyphthalic acid, which was obtained through the reaction of hexafluoropropene trimers with 4-hydroxyphthalic acid. Epoxy resin cured with PFPA was found to have several excellent properties. Its boilding water absorption was 0.45%, which is about a one-fourth that for conventionally cured epoxy resin. Its heat resistance was excellent, and its critical surface tension was almost the same as for PTFE.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170220330
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