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  • 11
    Electronic Resource
    Electronic Resource
    The structure and elasticity of polyurethane networks (1985)
    Springer
    Polymer bulletin 14 (1985), S. 295-300 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Model networks prepared from polyoxypropylenetriols (PPT) and diphenylmethane diisocyanate (MDI) in an excess of NCO groups were found to contain unusually small amounts of sol, ws, and to have high values of the equilibrium modulus, suggesting an additional crosslinking, probably due to the formation of trifunctional allophanate crosslinks. A comparison of the ws values with the theory of branching processes in which the formation of both urethanes and allophanates is considered allowed us to determine the possible extent of the allophanate reaction, and to calculate the concentration of elastically active chains contributed by PPT and allophanate crosslinks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00254952
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  • 12
    Electronic Resource
    Electronic Resource
    Cyclization in the reaction between diglycidylaniline and amine (1986)
    Springer
    Polymer bulletin 15 (1986), S. 389-396 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The reaction of diglycidylaniline (DGA) and N-methylaniline (NMA) was investigated by means of HPLC, and the products were identified by mass spectrometry. A number of cyclic products is formed. An eight-membered ring formed by the intramolecular reaction of the secondary amino group and the epoxy group in the DGA-aniline monoadduct is the main cyclic product. The monoadduct DGA-NMA yields a seven-membered ring by internal etherification only after the amine has been consumed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00265719
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  • 13
    Electronic Resource
    Electronic Resource
    Specific features of the kinetics of addition esterification of epoxide with the carboxyl group (1986)
    Springer
    Polymer bulletin 15 (1986), S. 215-221 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The kinetics of addition esterification involving epoxide and carboxyl groups in the presence of a tertiary amine was investigated using a model system phenylglycidyl ether — caproic acid. It has been found that the reaction has an induction period. By means of IR spectra it has been proved that the equilibrium formation of catalytically active species (complex acid-amine) is the cause both of nonconstant values of experimentally determined reaction orders and of the occurrence of the induction period. The controversial experimental results reported in the literature are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00255065
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  • 14
    Electronic Resource
    Electronic Resource
    Light scattering from dilute solutions of critically branched epoxy resins (1987)
    Springer
    Polymer bulletin 18 (1987), S. 329-336 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Critically branched polymers were prepared from the bifunctional 4,4′-diglycidyl-2,2-diphenylpropane (diglycidyl ether of Bisphenol A) and tetrafunctional poly(oxypropylene)diamine (Jeffamine D-400) at different distances from the gel point. Solutions of these samples in dimethylformamide were studied by static and dynamic light scattering. The results are discussed in terms of the classical Flory-Stockmayer theory and the percolation theory of gelation. The experimental results were found to be in agreement with the classical theory. The distribution functions of relaxation times were experimentally determined by the analysis of time autocorrelation functions obtained by quasielastic light scattering measurements on critically branched polymer solutions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00256233
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  • 15
    Electronic Resource
    Electronic Resource
    The relaxation and equilibrium behaviour of model polyurethane networks (1980)
    Springer
    Polymer bulletin 3 (1980), S. 497-503 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The mechanical, dielectric and rheo-optical behaviour of model networks prepared from OH-terminated poly(oxypropylene)triols and 4,4′-diphenylmethane diisocyanate with various molar ratios of hydroxyl to isocyanate groups, rH=0.95 to 1.7, was investigated. The observed independence of the stress-optical coefficient of rH indicates the homogeneity of networks. Networks prepared with rH≈1 exhibit a narrow transition zone indicating a narrow chain distribution. With increasing rh, the transition becomes distinctly broader; dielectric measurements are well correlated with the mechanical ones. The equilibrium modulus markedly decreases with increasing rH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00283826
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  • 16
    Electronic Resource
    Electronic Resource
    Brillouin scattering from epoxy resins and gels (1989)
    Springer
    Polymer bulletin 21 (1989), S. 641-648 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The isothermal curing process of the system diglycidyl ether of Bisphenol A/poly (oxypropylene) diamine (Jeffamine D-400) without and in the presence of solvent (Diglyme) was investigated by Brillouin spectroscopy for the stoichiometric amounts of epoxide and amine groups. The spectroscopic data have been explained in terms of the relaxing viscosity model in the former case and by the scattering of phonons by stationary heterogeneities in the latter one. It is suggested that these heterogeneities may be small air bubles released during curing and frozen in due to the high viscosity at and above the gel point.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00264147
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  • 17
    Electronic Resource
    Electronic Resource
    Formation of poly(urethane-isocyanurate) networks from poly(oxypropylene)diols and diisocyanate (1993)
    Springer
    Polymer bulletin 31 (1993), S. 83-88 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Reaction conditions leading to the smallest amount of unreacted isocyanate groups for the preparation of poly(urethane-isocyanurate) networks based on 2,4-tolylene diisocyanate and α,ω-dihydroxypoly(oxypropylene) (M n = 425−) were found. A tertiary amine, POLYCAT* 41, was used as a cyclotrimerization catalyst. The networks were prepared by prepolymer two-stage technique. The content of isocyanate groups in the prepolymers and networks was determined by potentiometric titration. Model reactions in 1,4-dioxane were used for the estimation of possible reaction intermediates during poly(urethane-isocyanurate) synthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298768
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  • 18
    Electronic Resource
    Electronic Resource
    Evidence of polyion hydration from X-ray and neutron small-angle scattering experiments (1981)
    Springer
    Polymer bulletin 4 (1981), S. 225-231 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The recently published small-angle scattering curves of semidilute solutions of poly (methacrylic acid) indicate some differences in neutron and X-ray data. At high degree of neutralization (α〉0.6), with increasing α the neutron intensity decreases and X-ray intensity increases. A new series of experiments confirms this apparent discrepancy. We suggest an explanation of the observed phenomenon, based on a simple model which considers hydration of macroions. Using the proposed model, about one water molecule is estimated to be in excess in the hydration shell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00256310
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  • 19
    Electronic Resource
    Electronic Resource
    Cure monitoring of epoxy resins by fluorescence quenching (1989)
    Springer
    Polymer bulletin 22 (1989), S. 585-592 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The effect of curing on the fluorescence intensity of 1,6-diphenyl-1,3,5-hexatriene (DPH) and 9,10-dimethylanthracene (DMA) was studied using two epoxide/amine systems. In the system diglycidyl ether of Bisphenol A (DGEBA)/1,3-diaminopropane the fluorescence intensity of DMA, If, increases with increasing conversion of epoxy groups; this is explained by means of a dynamic model of fluorescence quenching by dissolved molecular oxygen. Contrariwise, in the other system under study, DGEBA/poly (oxypropylene) diamine (JeffamineR D-400), If of the DPH probe decreases, which is interpreted by using the model of static fluorescence quenching. Both effects are suggested for use in the cure monitoring of epoxy resins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00718938
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  • 20
    Electronic Resource
    Electronic Resource
    Theoretical treatment of network formation by a multistage process (1987)
    Springer
    Polymer bulletin 17 (1987), S. 239-245 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A general scheme for a multistage process of network formation is formulated in which the Galton-Watson or universal consistency relation is assumed to be valid. The scheme is elaborated with the theory of branching processes with cascade substitution. Cyclization is postulated not to occur, substitution effects are allowed and can be incorporated in the probability generating functions (pgf).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00285356
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