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  • 1
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    Thermochemistry of model curing reactions of epoxy resins (1986)
    Springer
    Details
    Publication Date: 1986-05-01
    Print ISSN: 0170-0839
    Electronic ISSN: 1436-2449
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Springer
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    PAPER CURRENT
  • 2
    Electronic Resource
    Electronic Resource
    Excess volume of mixing and equation of state theories (1993)
    Springer
    Journal of solution chemistry 22 (1993), S. 399-425 
    Details
    ISSN: 1572-8927
    Keywords: Thermodynamics of mixtures ; equation of state theories ; excess volume of mixing ; interaction parameter ; binary mixtures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Equation-of state theories of Flory and of Sanchez and Lacombe describe both enthalpy and volume of mixing of binary systems using single component properties and only one binary parameter X12. We have evaluated this parameter from literature enthalpy data for numerous mixtures of two aromatic hydrocarbons, of alkanes with aromatic compounds, and of alkanes with carbonyl compounds. We have used this X12 for calculation of excess volumes and compared the results with our previously measured experimental data. The agreement was fair for mixtures of two nonpolar components. Nevertheless, mixtures containing either cyclohexane or benzene displayed anomalies that could be traced to special packing of molecules in these compounds when pure. For mixtures of carbonyl compounds with alkanes, the theories predicted the qualitative trends correctly, but the quantitative agreement was rather poor. These results tend to support a model in which the enthalpy(cohesive energy) is inversely proportional to volume (as in the theories considered) only for dispersive interaction. When polar-polar interactions are involved, the dependence of excess volume on the excess enthalpy is much weaker.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00647679
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  • 3
    Electronic Resource
    Electronic Resource
    Thermochemistry of model curing reactions of epoxy resins (1986)
    Springer
    Polymer bulletin 15 (1986), S. 439-443 
    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 heats of reaction of phenylglycidyl ether and N,N-methylglycidylaniline as model systems for two different types of epoxy resins with primary and secondary amine were determined. In all cases the heat of reaction was found to be dependent on the ratio of the reactant components. This dependence is probably due to the formation of various complexes via a hydrogen bond. It was also found that, while the heats of reaction of phenylglycidyl ether with primary and secondary amine are the same, the heats of reaction of N,N-methylglycidylaniline with primary and secondary amine differ significantly from each other.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00265726
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  • 4
    Electronic Resource
    Electronic Resource
    Heat capacities of water swollen hydrophilic polymers above and below 0°C (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 745-760 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The heat capacities of water swollen poly[2-(2-hydroxyethoxy)ethyl methacrylate] were determined in a DSC-2 calorimeter within the temperature range 220-350K for concentrations from 0 to 1,2g of water per 1g of the polymer. At temperatures above 0°C the partial specific heat capacity of water in gel is concentration independent and equal to the specific heat capacity of pure liquid water. It seems, therefore, that water does not form stable icelike structures near polymer chains. To analyze phase transformations of water in gel below 0°C, general thermodynamic equations were derived and used as a basis for suggesting criteria which allow to decide whether in a given experiment the phase transformation proceeded in an equilibrium way. In measurements below the melting point of ice the conditions for an equilibrium process consist in the preceding heating of the frozen sample to a temperature close to the melting point, followed by cooling to 220K. The assessed composition dependence of the melting point depression is consistent with the dependence of activity on concentration obtained from measurements of water vapour sorption at 35°C. Analysis of data on the heat capacity below 0°C led to the conclusion that at a water content of 0,4g/g and lower, or at temperatures below 250K the crystallization of water from gel was inhibited by kinetic factors originating probably in the reduced diffusivity of water in gel, due to the reduced mobility of polymer chains. Hence, non-freezing water need not be identical with “strongly bound” water; in the study of water structure in polymers based on heat capacities, preference should be given to data obtained at usual and elevated temperatures.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1979.021800318
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  • 5
    Electronic Resource
    Electronic Resource
    Sorption of water in hydrophilic polymers, 2Part 1: cf.1. Thermodynamics of mixing of water with poly(2-hydroxyethyl methacrylate) and with poly[2-(2-hydroxyethoxy)ethyl methacrylate] (1982)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 183 (1982), S. 1565-1575 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Sorption isotherms and heats of immersion of water in poly(2-hydroxyethyl methacrylate) (PHEMA) and in poly[2-(2-hydroxyethoxy)ethyl methacrylate] (PHEOEMA) were determined at 25°C and the Gibbs energy, enthalpy and entropy of mixing were calculated from the data. The results confirm that the physical state of the polymer plays a decisive role in the thermodynamics of sorption. At the temperature of measurement, pure PHEMA is in the glassy state and after sorption of a certain amount of water it passes into the viscoelastic state. Similar to other cases of mixing of a glassy polymer with a low-molecular weight liquid, the entropy and enthalpy changes are negative, with contributions due to the difference between the physical states of both pure components predominating in them. The thermodynamics of liquid mixtures can be used only for PHEOEMA which at 25°C is in the viscoelastic state. The mixing of water (especially of the first additions) with PHEOEMA is exothermal, being at the same time connected with a negative residual entropy, the effect of which predominates at 25°C. As a result, the affinity of water to the polymer, expressed through a change in the Gibbs energy, is comparatively weak. This is why in this system no strongly bound water is involved, even if the ΔH and ΔS values indicate some sort of increase in ordering during mixing.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1982.021830620
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  • 6
    Electronic Resource
    Electronic Resource
    A calorimetric investigation of interactions in aqueous solutions of poly(oxyethylene), 2.Part 1: cf.4. Determination of excess heat capacities and application of association theoryTo Prof. O. Wichterle on the occassion of his 75th birthday (1989)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 1345-1359 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Excess heat capacities are given as functions of composition and temperature for non-dilute aqueous solutions of poly(oxyethylene) and its oligomeric models, i. e. from the glycol monomer to tetramer and dimethyl ethers of these compounds. A theoretical model based on the concept of association equilibria was used to predict the excess heat capacities of aqueous mixtures of dimethyl ethers at 298K and 350K. Numerical values of parameters of the model were obtained by treatment of the heats of mixing reported in the first part of this study. It was sufficient to adjust two parameters of self-association of water, and for each system also the parameter characterizing hydration of ether groups in oligomers. The agreement between theory and experiment was very good for both enthalpy and heat-capacity data, with the exception of the concentration range rich in water, where the interaction scheme is probably more complicated.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1989.021900615
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  • 7
    Electronic Resource
    Electronic Resource
    Correlation of data on intrinsic viscosities in mixed solvents by means of the modified flory-huggins equationTo Professor O. Wichterle on the occasion of his 70th birthday (1983)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 184 (1983), S. 2081-2096 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An equation for the total sorption potential Y derived from the modified Flory-Huggins equation and containing concentration-dependent interaction parameters, including the ternary parameter χT, was used to correlate reported data on intrinsic viscosities in mixed solvents. Similarly to the evaluation of data on preferential sorption, the assumption of proportionality between the ternary parameter and the interaction parameter of components of the mixed solvent, g12, was successfully applied to the case of total sorption. The assumption proved to be useful in the treatment of 12 ternary systems, if the single-liquid approximation was employed. The calculated proportionality constant between the ternary parameter and g12 has properties similar to that evaluated from the data on preferential sorption. The conditions of occurrence of a maximum or minimum in the dependence of total sorption on composition are discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1983.021841013
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  • 8
    Electronic Resource
    Electronic Resource
    Composition dependence of the second virial coefficients for styrene/butadiene/styrene three-block copolymers and for mixtures of the respective homopolymers (1978)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 1815-1820 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The composition dependences of the second virial coefficients for styrene/butadiene/styrene three-block copolymers with Mn≈ 105 g.mol-1 were measured in toluene, 1,4-dioxane, isobutyl methyl ketone and isopropyl acetate at various temperatures; analogous measurements were made with mixtures of polystyrene and polybutadiene in toluene and 1,4-dioxane. The results were qualitatively compared with model calculations based on the relations derived by means of the perturbation theory.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1978.021790716
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  • 9
    Electronic Resource
    Electronic Resource
    The effect of specific interactions on the sorption equilibrium in the polymer/mixed solvent systemDedicated to Dr. Mr. Bohdanecký on the occasion of his 60th birthday (1985)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 186 (1985), S. 37-52 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Using the theory of association equilibria, equations are derived for preferential and total sorption into the coil for a ternary system containing inert liquid A, self-associating liquid B and polymer C, capable of specific interactions with component B. Due to strong interactions, the assumption of random mixing is not valid for this system. In preceding work differences between experiment and prediction based on the classical Flory-Huggins equation were formally described by the introduction of a ternary interaction term. For this particular system the ternary term may be interpreted as a consequence of the decrease in the entropy of mixing, caused by strong association of component B. On the contrary, if this component is bound to the polymer at the same time, the ternary term decreases. The equations derived in the paper lead to a reasonable fit with experimental data of the system benzene (A)/alcohol(B)/poly(methyl methacrylate)(C).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1985.021860105
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  • 10
    Electronic Resource
    Electronic Resource
    A calorimetric investigation of interactions in aqueous solutions of poly(oxyethylene), 1. Heats of mixing of oligomeric models (1987)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 379-394 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Heats of mixing with water as function of the composition of the mixtures for oligomeric models of poly(oxyethylene) at 25°C are reported, i. e. for compounds of the type XO(CH2CH2O)nX (where X = H or CH3 and n = 1, 2, 3, or 4) and CH3O(CH2CH2O)mH (where m = 1 or 2). These dependencies greatly depend on the character of the end groups and on the degree of oligomerization. A procedure has been suggested for the comparison between the heat of mixing of longer chains and that of shorter ones with elimination of the effect of end groups. On the same mass basis, longer chains release more heat than shorter ones in mixing with water for concentrated solutions; hence, one may assume some kind of cooperativity of ether oxygen atoms in the same chain by hydration.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1987.021880215
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