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  • Polymer and Materials Science  (15)
  • azlactones  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Polymeric Pd catalysts for the reduction of acetamidocinnamic acid azlactone and its solvolysis products (1992)
    Springer
    Russian chemical bulletin 41 (1992), S. 1858-1867 
    Details
    ISSN: 1573-9171
    Keywords: Pd catalysts on chiral polymers ; asymmetric reduction ; azlactones ; reductive aminolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Pd complexes have been obtained from linear and cross-linked copolymers ofR,S-, R-, andS-1-(4-vinylphenyl)ethylamine (1) with styrene and divinylbenzene. Reduction of these compounds gave catalysts which were active in the reductive solvolysis of α-acetaminocinnamic acid azlactone (2) and hydrogenation of the solvolysis products α-acetamidocinnamic acid (ACA), its esters, and its 1-phenylethylamide. The catalysts showed no enantioselective properties in the reductive hydrolysis, but were more active than the catalyst obtained in the absence of the polymer (the “monomeric” analog). The use of polymeric catalysts has shown that, in reductive aminolysis, the chiral nucleophile plays the dominant part in determining the stereoselectivity of the reaction, rather than the chiral ligand of the catalytic complex. The polymer matrix stabilizes the low-valent state of the palladium in the complex. In the hydrogenation of ACA and its esters, the catalyst on the cross-linked polymer is much more active than its “monomeric” analog, but showed no enantioselectivity. Hydrogenation of acetamidocinnamic acidR-andS-1-phenylethylamides on a chiral Pd-polymer catalyst occurred with double asymmetric induction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00863823
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  • 2
    Electronic Resource
    Electronic Resource
    Thermotropic liquid crystalline polymers-problems and trends (1984)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 6 (1984), S. 3-27 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A review is given in the field of liquid crystalline polymers having mesogenic groups in side branches and in the main chain. Conditions for liquid crystalline state formation are discussed in relation with chemical structure of monomeric units, molecular mess and type of mesogenic groups. Pathways to synthesize nematic, smectic, and cholesteric mesophases in polymers are discussed, peculiarities of structure and properties of polymeric mesophases and models of chain packing in them are analyzed. Electrooptical properties of such systems, when an electric and magnetic field is applied, are discussed-Frederick's effect, electrohydrodynclmic instability, “guest-host” effect, cooperative structural transi- tion induced by electric field, and some others. The possible directions of application of polymeric liquid crystals are considered.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1984.020061984101
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  • 3
    Electronic Resource
    Electronic Resource
    Structural and physical modification of thermotropic liquid crystalline polymers (1984)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 8 (1984), S. 47-61 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The structure and properties of thermotropic liquid crystalline polymers with side mesogenic groups are discussed. The regulation of physical and physico-chemical properties of such polymers is shown to be achieved both by the structure modification of macromolecules and by use of an electric field.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1984.020081984105
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  • 4
    Electronic Resource
    Electronic Resource
    Ring-opening metathesis polymerization of norbornenes with organosilicon substituents. Gas permeability of polymers obtained (1991)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 192 (1991), S. 1-9 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymers of norbornenes with SiMe3 and Si(Me2)CH2SiMe3 groups were synthesized and mass transfer properties of the polymers were studied. Ring-opening polymerizations of these monomers were realized in the presence of homogeneous WCl6-based and heterogeneous Re2O7-based metathesis catalysts. Introduction of silicon-containing groups in the polynorbornene main chain results in a drastic increase of the permeability (P) and diffusion (D) coefficients for different biatomic and multiatomic gases. Comparison of polymers having SiMe3 and Si(Me2)CH2SiMe3 substituents shows lower permeability and diffusion coefficients in the latter case. The combination of transport properties (Pi values) and separation factors aij = Pi/Pj of the two new silicon-containing polynorbornenes permits one to consider them as representatives of the most permeable and sufficiently permselective group of polymers. Transport properties of the polymers studied were analysed on the basis of the free volume approach.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1991.021920101
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  • 5
    Electronic Resource
    Electronic Resource
    Thermal decomposition of glassy poly(di-t-butyl fumarate) as a topochemical reaction (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 395-401 
    Details
    ISSN: 0887-624X
    Keywords: poly(di-t-Butyl fumarate) ; thermal decomposition ; kinetics ; autocatalysis ; solid-phase reaction mechanism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Decomposition of t-butyl carboxylate (TBC) groups in a glassy poly(di-t-butyl fumarate) (PDTBF) at 140-170°C proceeds with a sharp acceleration caused by interchain interaction of TBC and carboxylic groups. According to selective dissolution data, at 70% degree of conversion the reaction system contains both unchanged PDTBF and a final product: poly(fumaric acid). For TBC groups decomposition in di-t-butyl fumarate (DTBF)-styrene copolymers above their Tg an apparent rate constant of autocatalysis increases with the increase of DTBF content in copolymer. Together with previously obtained x-ray data these results lead to conclusions about the topochemical character of the PDTBF decomposition. The mechanism suggested includes thermal decomposition of TBC groups (initiation), autocatalytic growth of spheric clusters up to a critical size (an appearance of primary germs of the new phase), and growth and branching of thread-like germs. A mathematical model based on these assumptions describes quantitatively the kinetic data. © 1993 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080310212
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  • 6
    Electronic Resource
    Electronic Resource
    Rheology and morphology of polymer blends containing liquid-crystalline component in melt and solid state (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 363-372 
    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 rheological properties of polymer blends containing polysulfone and LC polyester have been investigated in terms of the morphology and physical-mechanical characteristics of the extrudates. The peculiarities of rheological behavior are connected with the morphology of stream, the latter being maintained also in solid extrudates. The reinforcement of an isotropic matrix by LC polymers as well as formation of an anisotropic surface layer leads to a specific change in the strength properties of compositions. A maximal increase in the strength and initial modulus was observed for blends containing not more than 10% LC polymer.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070420208
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  • 7
    Electronic Resource
    Electronic Resource
    Transport characteristics and other physicochemical properties of aged poly(1-(trimethylsilyl)-1-;propyne) (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 48 (1993), S. 1935-1944 
    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: Samples of poly[1-(trimethylsilyl)-1-propyne] were kept for about 4 years in ambient conditions. The permeability and diffusion coefficients were examined and found to be decreased by 1-2 orders of magnitude. To ascertain the nature of the changes underwent during long-term storage of this polymer, several physicochemical methods were applied: positron annihilation, wide-angle X-ray diffraction, spin probe, and density evaluation. These studies indicated that a decrease of free volume and more close chain packing took place during the aging process. IR spectroscopy and 13C-NMR showed that oxygen-containing products appeared in the polymer after long-term storage. This should result in a certain decrease in the rigidity of the backbone chains and more intensive interchain in-teractions, and, hence, in a decrease in the free volume of the aged polymer. © 1993 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070481107
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  • 8
    Electronic Resource
    Electronic Resource
    Comb-like polymers. Structure and properties (1974)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science: Macromolecular Reviews 8 (1974), S. 117-253 
    Details
    ISSN: 0076-2083
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 54 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1974.230080103
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  • 9
    Electronic Resource
    Electronic Resource
    Affinity chemotherapy and diagnostics using some novel polymeric hydrogels (1994)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 5 (1994), S. 634-644 
    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
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1994.220051002
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  • 10
    Electronic Resource
    Electronic Resource
    Estimation of free volume in poly(trimethylsilyl propyne) by positron annihilation and electrochromism methods (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 47 (1993), S. 85-92 
    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 free volume of poly(trimethylsilyl propyne) (PTMSP), a glassy polymer distinguished by extremely high gas permeability and diffusion coefficients, was determined by means of two probe techniques - the positron annihilation method and the electrochromism method. Lifetime analysis of positron annihilation spectra revealed an additional long-lived component that is not typical for most of previously studied polymers. A model that has been developed earlier predicts that this lifetime corresponds to the larger size of free-volume elements having an intrinsic radius of about 6 Å. Therefore, PTMSP should be similar to porous inorganic sorbents. A comparison with the literary data for zeolites and silica gel confirms this. According to the electrochromism method, the temperature dependence of the size of free-volume elements for PTMSP is much weaker than that for regular glassy polymers like polystyrene. It was concluded that the great free volume in glassy PTMSP is associated with very loose packing of the chains. © 1993 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070470111
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