Library

X
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
    Electronic Resource
    Electronic Resource
    Preparation and characterization of polyurethane-type macroazo initiators for block copolymerization (1993)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 194 (1993), S. 829-839 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The use of dipropylene glycol in the polyaddition of 2,2′-azobis(2-cyanopropanol) (ACP) with hexamethylene diisocyanate results in soluble polyurethane-type macroazo initiators (PUMAI) in high yields. By adjusting the amount of ACP used, the number-average molecular weight of the polyurethane segments was adjusted in the range from 2000 to 6000 at an azo content in the PUMAI's of 0,18 to 0,5 mmol/g-polymer (determined by UV). 13C NMR spectroscopy of the PUMAI's showed that no significant decomposition of azo groups occurred during polyaddition. At 80°C the PUMAI's initiated effectively the radical solution polymerization of vinyl monomers. As supposed from extraction results and the polymerization mechanism, block copolymers are formed. The whole process seems to be adequate for industrial applications.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1993.021940307
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Preparation of poly(urethane/vinyl) block copolymers initiated by polyurethane-type macroazo initiators (1993)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 194 (1993), S. 2335-2347 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(urethane/vinyl) block copolymers (PU-PV) were obtained in high yields by the polymerization of vinyl monomers (butyl methacrylate (BMA), ethyl acrylate (EA), and methyl methacrylate (MMA)) in the presence of polyurethane-type macroazo initiators (PUMAI). PUMAI was prepared via addition reaction of azodialcohol, dipropylene glycol and hexamethylene diisocyanate. The PU-PBMA's, as typical examples of PU-PV's were purified by solvent extraction. Characterization of the purified PU-PBMA's by 1H NMR, IR, together with extraction behavior, supported the block nature of PU-PBMA. Film tensile strength and elongation measurements in comparison with the corresponding blend samples also supported the block nature of PU-PV.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1993.021940817
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Radical block copolymerization by a novel bifunctional redox and azo compound (1992)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 333-335 
    Details
    ISSN: 0887-624X
    Keywords: block copolymerization ; radical copolymerization ; redox and azo initiation ; bifunctional initiator ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1992.080300219
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    A polymeric chiral surface functionality immobilized on uniformly sized macroporous polymer beads (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 2747-2757 
    Details
    ISSN: 0887-624X
    Keywords: polymeric chiral surface functionality ; uniform size ; macroporous polymer beads ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Uniformly sized functionalized macroporous polymer beads were prepared by either a classical copolymerization method or recently reported in situ surface modification method utilizing chiral methacrylamide as a functional modifier. To evaluate conformational and/or specific differences in their surface chiral functionality, we applied chromatographic evaluation techniques. The prepared modified beads were utilized as chiral stationary phase in high-performance liquid chromatography (HPLC). Those prepared by the in situ surface modification method tended to show higher chiral recognition ability than those by the classical copolymerization method, even if the equivalent amount of the chiral functional group was involved within polymer beads. Detailed chromatographic studies exhibited the in situ surface modification method could lead to polymeric methacrylamide functionality on the surface within relatively large pore size regions of the macroporous polymer beads, while the classical copolymerization method tended to form less polymeric surface functionality. The difference in the chiral surface functionality on both of macroporous polymer beads afforded drastic change in chromatographic chiral recognition ability. Complete resolution of a drug, thalidomide could be achieved on the chiral stationary phase with the polymeric chiral surface functionality, while no resolution was found on that with the monomeric one even if the same chiral methacrylamide was used as a modifier to prepare the chiral stationary phases. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2747-2757, 1997
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 5
    Electronic Resource
    Electronic Resource
    Nonclassical urea oligomers. IX. Photo-reducing nature of binuclear copper complexes of noncyclic pendant-type urea oligomersPaper VIII of this series: see Ref. 1. (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 285-299 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The octameric oligomers of 1-(N-substituted-carbamoyl)-aziridine, i.e., N-ureanized-oligo-ethylenimines, form Cu(II) complexes. When the N-substituents are phenyl(1, 3), methyl(2), and p-tolyl(4) groups, the main portions of the Cu(II)-complexes are binuclear. The binuclear oligomer-Cu(II) complexes showed characteristic properties of photo-reduction of Cu(II) species, giving rise to stable yellow Cu(I) species. The ease of photo reduction strongly depends on the oligomer structures, especially on the nature of the pendant-urea groups, i.e., 4 〉 1,3 〉 2. In the series of aromatic type urea-oligomers, highly stable photo-radicals were observed in ESR. By using an optically active oligomer (3) the molecular requirements for these characteristic properties were investigated with circular dichroism and cyclic voltammometry. And one of the plausible structures was deduced as the model of binuclear Cu(II) sites surrounded by oligomeric environments.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1988.080260128
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Preparations and properties of uniform size macroporous polymer beads prepared by two-step swelling and polymerization method utilizing divinyl succinate or divinyl adipate as a crosslinking agent (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 2767-2774 
    Details
    ISSN: 0887-624X
    Keywords: macroporous polymer beads ; divinyl succinate ; divinyl adipate ; two-step swelling ; polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Uniform size macroporous polymer beads were prepared through a typical two-step swelling and polymerization method utilizing divinyl succinate or divinyl adipate as well as ethylene dimethacrylate as crosslinking agents. Stable macroporous polymer beads with good size monodispersity and a slightly nonspherical shape were obtained by homopolymerization of divinyl succinate in cyclohexanol as porogen. BET measurements indicated that the beads prepared by homopolymerization of divinyl succinate and copolymerization of divinyl succinate with vinyl p-tert-butylbenzoate, as well as homopolymerization of ethylene dimethacrylate had relatively large specific surface area. In contrast, copolymerization of divinyl succinate with methyl methacrylate afforded beads having a very small specific surface area. Similarly, all the beads prepared using divinyl adipate had very small specific surface area, while size exclusion chromatography in tetrahydrofuran suggested that these beads acquired a porous structure as a result of swelling. When used as packing materials for high-performance liquid chromatography, the beads prepared with divinyl adipate showed unexpected molecular recognition toward flat solutes in reversed phase liquid chromatography in contrast to those prepared with ethylene dimethacrylate. Copolymerizations with methyl methacrylate led to a decrease in molecular recognition, while those with vinyl p-tert-butylbenzoate enhanced the selectivity. © 1996 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 7
    Electronic Resource
    Electronic Resource
    Organoaluminum catalysts for polymerization reactions. The effect of metal hydroxides on the catalytic activity of the Al(C2H5)3/H2O system (1973)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 163 (1973), S. 45-58 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die katalytische Aktivitat des Systems Al(C2H5)3/H2O wurde untersucht. Wäßrige Lösungen von anorganischen Basen wurden an Stelle von reinem Wasser mit Al(C2H5)3 in Toluol/Äthylather umgesetzt. Ein einheitliches, weiches, gelartiges Produkt wurde dabei erhalten (H2O :Al(C2H5)3 ∼ 1.0-1.5), im Gegensatz zum heterogenen Produkt, das mit reinem Wasser gebildet wurde. Die Polymerisation von Acetaldehyd mit dem System Al(C2H5)3/wäßrige Losung einer anorganischen Base verlief mit höherer Stereo-Regularität. Das Verhalten bei der Polymerisation und die stochiometrische Reaktion des Katalysators mit den Monomeren (Bildung von Äthylacetat) zeigten, daB kein bedeutsamer Unterschied zwischen den aktiven Spezies des Systems Al(C2H5)3/wäßrige anorganische Base und des Systems Al(C2H5)3/H2O besteht. Eine verbesserte stereospezifische Polymerisation in Anwesenheit von anorganischen Basen wird im Zusammenhaug mit der Bildung vernetzter Produkte im System Al(C2H5)3/H2O bei der Katalysator-Darstellung diskutiert.
    Notes: The catalytic activity of the system Al(C2H5)3/H2O was investigated. Instead of pure water aqueous solutions of inorganic bases were reacted with Al(C2H5)3 in toluene/diethyl ether media. A uniform soft gel-like product was readily obtained in this reaction (H2O/Al(C2H5)3 ∼ 1.0-1.5) differing from the heterogeneous nature of the product obtained with pure water. The polymerization of acetaldehyde proceeded with higher stereo-regularity in this system Al(C2H5)3/aqueous inorganic base. The polymerization behavior and the stoichiometric reaction between the catalyst and the monomer (ethyl acetate formation) indicate that there seem not to be significant differences in the active species of Al(C2H5)3/aqueous inorganic base and Al(C2H5)3/H2O systems. Improved stereospecific polymerization in the presence of inorganic bases is discussed with respect to the formation of a cross-linked product in the Al(C2H5)3/H2O system in the preparation of the catalyst.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1973.021630104
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Structure in solution of biscyclo(dipeptide) restricted by CSSC gauche effect (1981)
    New York : Wiley-Blackwell
    Biopolymers 20 (1981), S. 2485-2497 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Biscyclo(Cys-Sar) [I] and biscyclo(Cys-Pro) [II] were prepared by the extension of amino acid moieties from cystine. Compound I equilibrates between two rotamers around the CSSC bond of the cystine residue in methanol, showing dual negative CD transitions (CS-SC) at 270 and 255 nm, and dual S-S vibrations at 507 and 539 cm-1 in Raman spectra. In contrast, a conformation of P-helix type is suggested in CH3CN, which shows a distinct negative CD at 270 nm and only one Raman band at 507 cm-1 for the S-S bond. Compound II rotates freely in dimethylsulfoxide (Me2SO) but takes a relatively stable conformer of P-helix type in methanol, chloroform/Me2SO (9:1), and chloroform/trifluoroacetic acid (9:1). The conformation in chloroform is retained even on addition of trifluoroacetic acid. A more complete conformation of compound II in water was determined from the negative CD of S-S transition and 1H-nmr spectra of the Cys-β-CH2 protons.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1981.360201202
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Telechelic polystyrene obtained by degradation of polyurethane-polystyrene block copolymers (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 195 (1994), S. 413-425 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polystyrene with one or two terminal hydroxyl groups was obtained in a high yield (88-90%) from polyurethane-polystyrene block copolymers (PU-PS). The block copolymers were prepared by radical polymerization of styrene with a polyurethane-type macroazo initiator, and then the urethane bonds were degraded with 2-aminoethanol. The purity of the hydroxylated polystyrene thus obtained, which consists predominantly of the dihydroxy-telechelic component, was much higher (ca. 90%) than that of polystyrene obtained by conventional radical polymerization using the corresponding low-molecular-weight azo initiator 2,2′-azobis(2-cyanopropanol) (ca. 80% mono- and dihydroxylated polystyrene). Formation of a predominantly telechelic HO - PS - OH was confirmed from the results of the polyaddition reaction of the hydroxylated polystyrene with a diisocyanate.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1994.021950203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Synthesis and metal binding properties of novel sulfur-containing functional oligomerPart 8 of “Non-Classical Urea Oligomers” series for Part 7, see ref. 1. (1980)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 3359-3368 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and metal ion binding properties of a new class of functional oligomers are described. Oligo[1-(N-phenylthiocarbamoyl)aziridine] (DP ca. 8) and its analogs are prepared by ring-opening oligomerization of the corresponding aziridine monomers in good yields. These oligomers contain sulfur groups capable of binding “soft” metal ions, and the selective binding properties of the novel oligomer for Cu(II) and Hg(II) ions are investigated by liquid-solid adsorption and liquid-liquid extraction experiments.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1980.170181203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...