ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 0749-1581
    Keywords: Thyrsiferol ; Thyrsiferyl acetate ; NOE ; Spectral assignments ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The assignment of all reasonances in the 13C and 1H NMR spectra of thyrsiferyl acetate has been made through the application of 2D NMR experiments, together with the use of difference NOE spectroscopy.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    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: A descriptive model was developed, using viscometry and light scattering, that explains the anomalous rheological behavior of solutions of amphiphilic acrylic copolymers upon the addition of water. The rheological behavior can be explained by considering the relative magnitudes of three interactions: the intra-and intermolecular electrostatic interactions between the ionizable acid groups in the copolymer, the intramolecular hydrophobic in-teractions, and the intermolecular hydrophobic interactions. The initial addition of water enhances the ionization of the acid groups, causing the electrostatic interactions between the acid groups to dominate the other two interactions. This leads to expansion of the polymer molecules and, consequently, to a relatively constant viscosity during dilution with water. Upon attaining the maximum ionization of the acid groups on the chain, the intra-molecular hydrophobic interactions dominate the electrostatic repulsion, and the chains start to contract. Further addition of water leads to aggregation of the polymer chains into large polymolecular domains, resulting in a sharp decrease in the viscosity. Intermolecular hydrophobic interactions dominate the rheological behavior in this stage of water dilution. © 1996 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 36 (1988), S. 141-163 
    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: A previously reported synthetic procedure was used to graft oligo-p-hydroxybenzoic acid (oligo-PHBA) to COOH-functional acrylic copolymers. Most of the products were side-chain LC copolymers. Length of the mesogenic oligo-PHBA groups averaged up to five aromatic rings per group. Because these long mesogenic groups have a strong tendency to form LC domains, it was possible to prepare LC side-chain copolymers having as little as 5 mol % of mesogenic monomer. Thus this synthetic procedure provides a versatile route for exploration of the properties of LC copolymers having relatively few but especially effective mesogenic groups. The potential utility of such LC copolymers as binders for nonbake coatings was assessed. Variables studied were molecular weight and Tg of the acrylic copolymer backbone, number and average length of oligo-PHBA segments, and the presence or absence of a flexible spacer between the acrylic backbone and the PHBA segments. Optimum LC copolymers have moderate (15,000-30,000) Mn, low (-10°C) backbone Tg, and low (5-7.5 mol %) population of long (5 PHBA units) oligo-PHBA units. Such copolymers have two major advantages as coatings binders: They form concentrated, stable, low-viscosity dispersions in common solvents, a very desirable characteristic for application. Coating films have excellent adhesion to metal, and they have an extraordinary combination of hardness (H-2H) and impact resistance (〉 80 in. Ib). These properties are key indicators of coating performance and indicate that LC copolymers have excellent potential for use as binders for nonbake coatings. Other properties remain to be investigated.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    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: A commercial hexakis(methoxymethyl)melamine (HMMM) resin was fractionated (1) by crystallization of the hexane-soluble fraction from hexane and (2) by partitioning the hexane-soluble and hexane-Insoluble fractions between alumina and various solvents. Crystallization afforded hexakis(methoxymethyl)melamine (1) of 90 to 95% purity. Partitioning afforded 12 fractions with altered proportions of polar and nonpolar species; the least polar fraction was spectroscopically and chromatographically similar to the crystallized material. Relative reactivities of certain fractions were estimated by 1H NMR studies of the rates of reaction with neopentyl alcohol in the presence of catalytic amounts of p-toluenesulfonic acid (p-TSA). It was found that the reactivity of fractions, rich in less-polar species, was substantially greater than that of the commercial HMMM resin, whereas reactivity of fractions, rich in polar species, was less. Reactivity was especially enhanced by removal of all active hydrogen species, notably those containing NH groups. A practical consequence of this result was that fully formylated and alkylated melamine resins could crosslink with polyols at substantially lower temperatures than the commercial HMMM resin, which contained NH groups. Therefore, room-temperature crosslinking was feasible.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 29 (1984), S. 3213-3215 
    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
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 37 (1989), S. 1063-1078 
    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: Carboxyl functional liquid crystalline (LC) acrylic copolymers were synthesized and were compared with carboxyl functional control copolymers of M̄n about 5000-15,000. Both types were crosslinked with a hexakismethoxymethyl melamine (HMMM) resin at 150°C, a temperature below the clearing points of the LC copolymers. Birefringent phases were visible in the crosslinked films made from LC polymers. FT-IR indicated the presence of unreacted COOH in all crosslinked materials. Unreacted COOH groups in crosslinked LC copolymers appeared only slightly higher than those in crosslinked amorphous copolymers. The potential utility of these LC copolymers as binders for thermosetting coatings was assessed. Variables studied were HMMM content, the length of PHBA grafts, Tg and M̄n of the acrylic copolymer backbone, and functionality. Optimum LC copolymers have low backbone Tg (〈O°C) and low functionality (〈 7.5 mol %). Cured films of such copolymers have both high hardness (〉 35 KHN), high impact resistance (〉 80 in. ib), excellent adhesion, and good solvent resistance.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 1609-1618 
    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: Oligomers derived from terephthalic acid and 1,6-hexanediol or 1,10-decanediol have been chemically modified through end-grafting with succinic anhydride or trimellitic anhydride followed by glycidyl neodecanoate. The grafted oligomers are paste-like semisolids or viscous liquids at room temperature. As the grafted oligomers are heated, their viscosity goes down to a minimum, then up to a maximum, and then down again. Combined DSC, crossed polarizing microscopy, and wide-angle x-ray diffraction indicate that the grafted oligomers form crystalline domains dispersed in amorphous phase. The grafted oligomers are soluble in common organic solvents, such as toluene, at lower concentrations (〈14-51 wt %) and form stable dispersions at higher concentrations. High solid coatings formulated with mel-amine or isocyanate resins gave glossy films with excellent combined hardness and impact resistance. © 1996 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    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: 13C-nuclear magnetic resonance (NMR) spectroscopy was employed to study the linkages in three commercial fully methylocated melamine-formaldehyde (HMMM) resins and their partially self-condensed resins by acid catalysis, in order to probe the structures linking melamine units. Distortionless enhancement by polarization transfer (DEPT) experiments show that the partially self-condensed resins contain both methylene ether and methylene linkages between melamine units. The extent of these linkages were estimated by quantitative 13C-NMR spectroscopy using inverse gated decoupling techniques. The results show that the ratios of methylene ether and methylene linkages to the triazine moiety vary from resin to resin. © 1996 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymer nanoparticles were prepared from monomers such as styrene (St), butyl methacrylate (BMA), butyl acrylate (BA), methyl methacrylate (MMA), and methyl acrylate (MA) using a modified microemulsion polymerization process. With this process high polymer: surfactant weight ratios (7 : 1 or greater), relatively concentrated (10-30 wt.-%) latexes and small (10-20 nm) particle diameters were attained. Nucleation mechanisms were investigated through observations of the particle size change during the polymerization.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 0173-0835
    Keywords: Two-dimensional zymography ; Photorhabdus luminescens ; Protease ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Two-dimensional zymography which combines two-dimensional electrophoresis with zymography was used to analyze proteases and other proteins produced by different phase variants of two strains of Photorhabdus luminescens. Both the primary and secondary phases of P. luminescens strains Hp and Hm secreted proteases. The protease in P. luminescens Hp has a molecular weight (Mr) of 57 000 and an isoelectric point (pI) of 4.4 whereas that in P. luminescens Hm has an Mr of 59 000 and pI of 4.9. Several putative protease degradation products were clearly visible in the zymograms from both bacterial strains. Two-dimensional zymography also showed that several secretory proteins were present only in particular phase variants and therefore could be used as specific markers. Unexpectedly, the two-dimensional zymography revealed that a nonsecretory protease with an Mr of 47 000 and a pI of 4.0 was present in the cell extracts of all phases of both P. luminescens Hp and Hm. The application of the two-dimensional zymography for the identification of other enzymes was also discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...