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  • 1
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The potentiometric and viscosimetric titration curves of poly(N-acetyldehydroalanine) (PNAcDHA) were compared with those of the nucleic acid base-containing dehydroalanine backbone polymers poly{(+ -) and (-)- [2-(thymin-1-yl]{propanoamido}propenoic acid} (PTDHA and P(-)TDHA)). The behavior of PNAcDHA was similar to polyacids such as poly(acrylic acid), but PTDHA and P(-)TDHA displayed very strong nearest neighbor interactions, since the pH curves had an additional inflection at half neutralization that was sensitive to the ionic strength of the medium and the viscosity curves showed little expansion of the polymer coil with increasing ionization. NAcDHA-TDHA copolymers were prepared which showed similar behavior. These results suggested that PTDHA and P(-)TDHA were extended and conformationally restricted in aqueous solution compared to PNAcDHA, findings that agreed with the results of spectroscopic studies of these polymers.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 39 (1988), S. 13-17 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Synthese und Eigenschaften einiger neuer funktioneller Oligomere sowie daraus erhaltener funktioneller und segmentierter Polymere werden beschrieben. Im ersten Teil der Arbeit werden Synthese und Eigenschaften von hochentwickelten segmentierten Konstruktionspolymeren behandelt. Die Polymere enthalten als starre Segmente vernetzte Bereiche; diese sind durch lineare Spacersegmente verbunden, die aus thermoplastischen Oligomeren mit funktionellen Endgruppen gebildet werden. Die Struktur-Eigenschafts-Beziehungen werden diskutiert. Der zweite Teil der Arbeit berichtet über die Synthese und mögliche Anwendungen von neuen funktionellen Oligomeren und Polymeren, die Cyclophosphazen-Einheiten enthalten. Besondere Aufmerksamkeit wird funktionellen Polymeren mit bioaktiven Aziridinylcyclophosphazen-Einheiten gewidmet, die durch spezielle biologisch abbaubare Spacer verbunden sind.
    Notes: Syntheses and properties of some novel functional oligomers and functional or segmental polymers thereof are reported. First part of the paper concerns the synthesis and properties of high performance segmental engineering polymers. These polymers contain crosslinked network units as rigid segments, linked by linear spacers, derived from the functionally terminated thermoplastic oligomers. Structure-properties relationships are discussed. Second part of the paper refers to the syntheses and possible applications of novel functional oligomers and polymers, containing cyclophosphazene moieties, particular attention being paid to the functional polymers with bioactive aziridinylcyclophosphazene units linked by specific biodegradable spacers.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alternating copolymers containing 4,4-isopropylidene-bisphenol (BPA) and comonomers with various degrees of polarity have been evaluated to find comonomer structures which provide low melt viscosity and good thermal stability. The materials were prepared by pyridine-catalyzed nucleophilic displacement reactions similar to that for the preparation of BPA polycarbonate. The molecular weights of the polycarbonates depend on the concentration and nucleophilicity of the attacking diol and the concentration and stability of a colored pyridine-chloroformate adduct formed during polymerization. The greatest thermal stability occurs for BPA-DMS and BPA-DEG. Thermomechanical flow measurements and Tg measurements were used to evaluate melt viscosity. The shapes and magnitudes of the Tg vs. Tf curves are sensitive to the copolymer chemical structure.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Water-soluble polynucleotide analogs having a poly(N-acyldehydroalanine) {poly(α[-(N-acylamino)acrylate])} backbone were studied by 360-HMz 1H-NMR, UV, and CD spectroscopies. Significant UV hypochromicity values for the polymers versus monomer model compounds as well as peak shifts in the NMR spectra implied a high degree of base stacking in these systems. The CD spectrum of poly{(-)-2-[2-(thymin-l-yl) propanoamido] propenoic acid} (p(-)TDHA), having an optically active side chain, was remarkably insensitive to the degree of neutralization of the polymer, but was very sensitive to the ionic strength of the solution. Continuous variation mixing experiments revealed no base-pairing interactions between complementary charged polymers, and weak interactions between charged and uncharged polymers and model compounds. These results suggest that the polymers are conformationally restricted in solution.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 4,6-Tetrachlorocyclotriphosphazene-2-spiro-2′-dinaphtho [1,2-d:2,1-e] [1,3,2]dioxaphosphepin (1a) and the dinaphtho [2,1-d:1,2-e] derivative (1b) were synthesized and identified on the basis of elemental and spectral (MS, IR, UV, 1H and 31P NMR) analysis. The anticancer activity of the new isomers against P388 leukemia was studied in vivo and discussed in terms of their electronic structures. A strict correlation was found between the resonance effects in the particular isomers and their antitumor activities.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0887-6258
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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