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  • 1
    Electronic Resource
    Electronic Resource
    Symmetric Block Oligomers. Gelation characteristics by DSC (2000)
    Springer
    Journal of thermal analysis and calorimetry 61 (2000), S. 551-564 
    Details
    ISSN: 1572-8943
    Keywords: amphiphile oligomers ; DSC ; thermo-reversible gelation ; water states
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Symmetrical block oligomers having in common terminal groups (A) consisting of polyoxyethylene (20) stearyl ether are materials of pharmaceutical and cosmetic interest. Phase properties of their aqueous systems and amounts of water typologies were determined by differential scanning calorimetry (DSC). The overall amount of water absorbed by each investigated oligomer was not significantly influenced by the type of central bridging block, whereas the amount of free water decreased with increasing oligomer concentration in the gel. A number of 60–70 moles of water was found to solvate the oligomer chain. The oligomers studied presented a thermo-reversible gelation with and precipitation under determined temperature conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010133904733
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  • 2
    Electronic Resource
    Electronic Resource
    Hybrid copolymerization of alkyl vinyl ethers with glycidyl ethersCorrected proofs Received October 3, 1983 (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 28 (1983), S. 3651-3663 
    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: Homopolymerization and copolymerization experiments of isobutyl and dodecyl vinyl ether with propylene oxide, and some glycidyl ethers have been carried out by using both conventional cationic initiators (BF3, BF3·OEt2) and 4-chlorophenyldiazonium tetrafluoborate as cationic photoinitiator. Conventional polymerization experiments performed under vacuum at low and room temperature gave rise to a mixture of the two homopolymers, indicating that the epoxide and vinyl ethers are incompatible with respect to chemical reactivity and that apparently no hybrid copolymerization occurs. Analogous results were obtained in parallel photoinitiated polymerization experiments.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1983.070281206
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  • 3
    Electronic Resource
    Electronic Resource
    Chiral liquid-crystalline polymers. XI. Thermotropic behavior and chiroptical properties in solution of a new series of optically active poly (ester β-sulfide)s (1990)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 3541-3550 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and characterization are described of a series of optically active semiflexible poly(ester β-sulfide)s 6*Sn with repeating units constituted by two p-oxybenzoyl diads spaced in an alternating fashion by a sulfide-containing polymethylene segment of variable length (n = 2-10) and a chiral (R)-3-methylhexanediyl segment of high enantiomeric purity. The polymers were prepared with good yields and relatively high molecular weights and narrow degrees of dispersity by a Michael-type polyaddition reaction of bis-thiols to the same chiral mesogenic bisacrylate monomer. Data are reported on the characterization of their chiroptical properties in dilute solution and thermal-optical properties in the bulk, with attention being devoted to the distinct odd-even alternations of the cholesteric-isotropic melt transition parameters. A comparison of the mesomorphic behavior and relevant thermodynamic quantities is presented between the present series of polymers and the achiral analogues of series 6Sn as well as the chiral, positional isomers of series mS6*. The dependence of the overall properties and their trends on very subtle structural changes is stressed, thus highlighting the critical interconnection between mesogenic cores and spacer segments in semiflexible liquid-crystalline polyesters.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1990.080281302
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  • 4
    Electronic Resource
    Electronic Resource
    Mesomorphic polyacrylates containing isomeric methyl-substituted azobenzene mesogens (1991)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 29 (1991), S. 1865-1873 
    Details
    ISSN: 0887-624X
    Keywords: azobenzene ; polyacrylates ; liquid crystals ; photoresponsive polymers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and characterization are reported of two new series of structurally isomeric polyacrylates containing the azobenzene moiety spaced away from the backbone by a hexamethylene spacer and substituted in 4-position with linear alkoxy groups (C1—C6, C10) and with a lateral methyl group in 2′- or 3′-position. Thermal optical and X-ray analyses of the prepared polymer samples, with molecular weight ranging from 50 × 103 to 35 × 104 Dalton (M̄w/M̄n = 2-3), provide evidences for the establishment of liquid crystalline behavior in the melt in a fairly broad range of temperature. In any case, quenching from the mesophase allows for the lock-in of the liquid crystalline structure in the glassy state. The presence of the lateral methyl-substitutents causes a drop as high as 50-100 K. in the stability of the mesophase with respect to the corresponding samples of the methyl-unsubstituted series. A parallel depletion of the smectogenic character is also observed. Typical even-odd effects on the isotropization temperature and relevant thermodynamic parameters have been detected along with the formation of interdigitated smectic structures.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1991.080291304
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  • 5
    Electronic Resource
    Electronic Resource
    Chiral liquid-crystalline side chain polymers by enantioselective modification of prochiral parent polymers (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 3 (1991), S. 307-314 
    Details
    ISSN: 0899-0042
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation is reported of two side chain polyacrylate samples 1a,b containing a sulfide group linked to the mesogenic core. By oxidation with a preferentially chiral oxaziridine, samples 1a,b were chemoselectively and enantioselectively converted to the corresponding sulfoxide containing polymers 2a,b with an estimated 20% asymmetric induction. The mesophasic behaviour of the parent and oxidized polymer samples is analyzed by thermal and optical techniques. The modification of the prochiral sulfide groups into chiral sulfoxide groups slightly depresses the propensity of the resulting polymers to give stable and persistent mesophases.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530030415
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  • 6
    Electronic Resource
    Electronic Resource
    An X-ray diffraction study of the different nematic mesophases of liquid-crystalline poly(urethane-ester)s (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 699-705 
    Details
    ISSN: 0887-6266
    Keywords: liquid crystal ; poly(urethane-ester) ; cybotactic nematic ; x-ray diffraction ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An x-ray investigation on powder specimens and stretched oriented fibers of poly(urethaneester)s TDI-CmCn, derived from various mesogenic alkylene di[4-(ω-hydroxyalkyloxy-4-oxybenzoyl)oxybenzoate]s (CmCn; m = 2, 4, or 6, and n = 4, 6, 8, or 10) and 2, 4-toluenediisocyanate (TDI), is reported. Evidence is provided for the formation of two different nematic mesophases in the polymers, namely a cybotactic nematic and a conventional nematic mesophase. Whereas samples TDI-C2C6, TDI-C6C4, and TDI-C6C10 formed one cybotactic nematic mesophase, samples TDI-C4C6, TDI-C6C6, and TDI-C6C8 exhibited both cybotactic nematic and conventional nematic mesophases in a sequence with increasing temperature, which were connected by a first-order transition. The analysis of the various features of the small-angle x-ray diffraction patterns indicates that two structural arrangements, namely smectic C-like and conventional nematic structures, coexist inside the cybotactic nematic mesophase of these poly(urethane-ester)s. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1995.090330419
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  • 7
    Electronic Resource
    Electronic Resource
    Editorial (1996)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 7 (1996), S. 341-341 
    Details
    ISSN: 1042-7147
    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
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Nuclear magnetic resonance spectra and structure of some alkyl vinyl sulphidesPresented in part at the IVth Symposium on Organic Sulfur, Venice, Italy, 15th to 20th June, 1970. (1970)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 2 (1970), S. 409-421 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The NMR spectra of eight alkyl vinyl sulphides have been analyzed and the parameters compared with those obtained from an analogous series of oxygen derivatives. It is shown that a definite parallelism exists between chemical shifts and H—H coupling. Difference in absolute values have been explained by mesomeric interaction involving the ability of sulphur to accommodate a decet of electrons in its valence shell. By analogy with alkyl vinyl ethers, it is possible to predict a similar correlation between the spectral characteristics and relative reactivity of vinyl sulphides in cationic polymerization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270020413
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  • 9
    Electronic Resource
    Electronic Resource
    Stereoregularity and dipole moments of optically active poly-alkyl-vinyl-ethers (1968)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 112 (1968), S. 197-209 
    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: Dipolmomente einiger Proben verschiedener Stereoregularität von Poly-[(S)-1 -methyl-propyl]-vinyläther (A) und Poly-[(S)-2-methyl-butyl]-vinyläther (C) wurden bestimmt und mit den Ergebnissen von Messungen an Proben mit vergleichbarer Stereoregularität von Polyisopropylvinyläther (B) und Polyisobutylvinyläher verglichen.Es ergab sich: (a) keine bemerkenswerte Abhängigkeit der Dipolmomente von der Steroregularität, mit Ausnahme von (B), dessen am meisten isotaktische Fraktion das niedrigste Dipolmoment aufweist; (b) daß das Dipolmoment der am meisten stereoregulären Fraktion von (A) höher ist als das der entsprechenden Fraktion der nicht optisch aktiven Modellverbindung (B); (c) daß für die Fraktionen, die eine hohe und vergleichbare Stereoregularität besitzen, die Dipolmomente für (A) und (B) niedriger sind, weil dort das an der Verzweigung liegende Kohlenstoffatom der Seitenkette der Hauptkette näher ist.Diese Daten können aus den Unterschieden in den Konformationsgleichgewichten verstanden werden, die für die Hauptkette solcher gelöster Polymeren zu erwarten sind.
    Notes: Dipole moments of some samples having different stereoregularity of poly-[(S)-l-methyl-propyl]-vinyl ether (A) andn poly-[(S)-2-methyl-buthyl]-vinyl ether (C) have been determined and compared with those of samples having comparable stereoregularity of polyisopropyl-vinyl ether (B) and poly-isobutyl-vinyl ether (D).The results indicate: (a) no remarkable dependence of dipole moments on stereoregularity, except for (B), of which the most isotactic fraction has the lowest moment; (b) the dipole moment of the most stereoregular fraction of (A) is higher than that of the corresponding fraction of the non optically active model compound (B); (c) for fractions having high and comparable stereoregularity, the dipole moments are lower in the case of (A) and (B), in which the branched carbon atom of the side group is nearer to the main chain.These data can be interpreted on the basis of the differences in conformational equilibria expected for the main chain of such polymers in solution.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1968.021120117
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  • 10
    Electronic Resource
    Electronic Resource
    Stereoselectivity in vinylethers polymerization (1969)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 7 (1969), S. 121-127 
    Details
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1969.110070207
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