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  • 1
    Electronic Resource
    Electronic Resource
    Etude des prépolymères époxydes par chromatographie et 1H NMR à 350 MHz (1983)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 184 (1983), S. 411-429 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The epoxy resins (DGEBA) obtained from 4,4′-isopropylidendiphenol (bisphenol A) and 1-chloro-2,3-epoxypropane (epichlorohydrin) and synthetized by the “taffy” process were found to consist of oligomers. The composition of prepolymers could be deduced from gel permeation chromatography (GPC), and particularly by high pressure liquid chromatography (HPLC). In the more resolved HPLC spectrum each oligomer was found to be accompanied by satellite peaks. The functionality of the prepolymers, determined by 1H NMR spectroscopy and cryometric or vapour pressure osmometric measurements was found to be less than two. These phenomena are due to the existence of abnormal chain ends having no epoxy group. The structure of the main components spearated by preparative GPC was studied by 1H NMR. For the impurities, the two indentified structures of chain ends are primary and secondary alcohol functions. Finally the compositions of three DGEBA were determined.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1983.021840216
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  • 2
    Electronic Resource
    Electronic Resource
    Résines époxydes, 3.Partie 2: cf.2. Etude de quelques prépolymères époxydes bromés par GPC, HPLC et NMR (1984)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 185 (1984), S. 2269-2281 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Examinations by GPC, HPLC and NMR of several commercial prepolymers containing epoxy groups show that they are based on bisphenol A (DGEBA) and brominated bisphenol A (DGEBtBr). In some cases, brominated monepoxides are also added to the mixture to diminish its viscosity. Consequently, the three-dimensional networks resulting from the polycondensation of brominated resins with diamines can be greatly affected by the presence of these monoepoxides that modify the epoxy/amine ratios.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1984.021851104
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  • 3
    Electronic Resource
    Electronic Resource
    Etude du prépolymère époxyde par chromatographie et 1H NMR à 350 mhz, 2Partie 1: cf. 3. (1984)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 185 (1984), S. 297-316 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The epoxy resins (TGMDA) obtained from 4,4′-methylenedianilic (2) and 1-chloro-2,3-epoxypropane (epichlorohydrin) were found to consist of oligomers with large distribution of molecular weights and functionalities. The structure of the main components separated by preparative gel permeation chromatography and by high pressure liquid chromatography (HPLC) was studied by 1H NMR. The best separation was obtained by HPLC on a preparected TGMDA with tert-butyl isocyanate at 60°C. For the impurities, as found with DGEBA prepolymers, we identified primary and secondary alcohol groups on chain ends but also secondary amino groups inside the oligomer chains.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1984.021850207
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  • 4
    Electronic Resource
    Electronic Resource
    Study on the mechanism of 1-cyanoguanidine cure of epoxy resins using model compounds (1987)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 7-19 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The mechanism of the reaction of 2,3-epoxypropyl phenyl ether (2), as a model compound, with 1-cyanoguanidine (3), for which different pathways have been proposed, is investigated using HPLC and 1H NMR spectroscopy. The effect of stoichiometric ratio, temperature and catalytic reagent was studied. It was found that, independent on the stoichiometric ratio, at low temperature, etherification and addition at the primary amino group takes place and reaction of the cyano group only to a low extend. At higher temperature, HPLC diagrams show different peaks indicating a different mechanism.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1987.021880102
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  • 5
    Electronic Resource
    Electronic Resource
    Comparison of microwave and thermal cure of an epoxy/amine matrix (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 233-239 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: An investigation was carried out into the effect ofa microwave cure on an epoxy prepolymer with a cycloaliphatic diamine mixture, as compared to a standard thermal cure. The microwave waveguide and process (propagation mode TE01) were adjusted to obtain large homogeneous samples. The extent of reaction, x, was measured during the microwave processing by size exclusion chromatography and differential scanning calorimetry. A good estimate of x was found using a modified DiBenedetto equation correlating x and the glass transition temperature Tg. The homogeneity of the samples was checked during the last steps of cure, showing the efficiency of the microwave processing and waveguide. The influence of the nature of the mold (metallic or dielectric) on the reaction kinetic was also investigated. Samples cured by both thermal and microwave processing were characterized by dynamic and static mechanical properties and then compared with those of fully crosslinked networks, i.e., postcured at a high temperature.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350303
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  • 6
    Electronic Resource
    Electronic Resource
    Prediction of the glass transition temperature of cycloaliphatic amine-epoxy networks (1991)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 29 (1991), S. 981-987 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Stoichiometric, completely cured binary or ternary mixtures of the diglycidylether of bisphenol A (DGEBA), isophorone diamine (IPD), and trimethylcyclohexylamine (TMCA) monomers were studied by differential scanning calorimetry. The relations between the glass transition temperature Tg and the structure of the copolymer networks were investigated. Good predictions of Tg can be obtained on the basis of the following hypothesis: (1) the molar contributions MiT-1gi to the “copolymer effect” of difunctional groups are additive, (2) the crosslinking effect can be expressed by the DiMarzio relation in which the molar contribution of crosslink mers is an increasing function of the stiffness of linear segments. For the seven systems under study, the deviation between calculated and experimental Tg values is within experimental scatter.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1991.090290808
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  • 7
    Electronic Resource
    Electronic Resource
    Measurement of the extent of reaction of an epoxy-cycloaliphatic amine system and influence of the extent of reaction on its dynamic and static mechanical properties (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 46 (1992), S. 859-871 
    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: An investigation was carried out into the effect of the extent of reaction on the mechanical properties, in a mixture of an epoxy prepolymer and a cycloaliphatic diamine, above the gel point. First, the most adequate technique to approach the extent of reaction was chosen between differential scanning calorimetry, Fourier transformation infrared, and size exclusion chromatography. It was found that the differential scanning calorimetry gave a good estimate of the extent of reaction, measuring the glass transition temperature and using a modified DiBenedetto equation. Dynamic mechanical properties and static mechanical properties are shown to be highly dependent upon the extent of reaction. The β relaxation was found to be responsible for the fracture properties at room temperature through the changes in extent of reaction. © 1992 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070460513
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  • 8
    Electronic Resource
    Electronic Resource
    Isothermal curing of an uncatalyzed dicyanate ester monomer: Kinetics and modeling (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 1441-1452 
    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 isothermal cure of a dicyanate ester monomer has been studied under different atmospheres (air and argon) without any catalyst, by following the evolutions of both glass transition temperature and conversion. Independently of both atmosphere and temperature of cure, there is a unique one-to-one relationship between these two parameters, correctly described by a restated DiBenedetto's equation. The chemical kinetics are satisfactorily modeled with two competing reactions schemes, which are second-order and second-order autocatalyzed, the latter displaying more relative importance under air-curing conditions. Whatever the cure temperature may be, gelation occurs around 0.60 conversion under air, whereas the theoretical xgel = 0.50 is experimentally observed under argon. The time-temperature-transformation diagrams have been established. © 1993 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070490812
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  • 9
    Electronic Resource
    Electronic Resource
    Influence of chain flexibility and crosslink density on mechanical properties of epoxy/amine networks (1991)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 31 (1991), S. 1572-1580 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: Blends of a bisphenol A diglycidyl ether prepolymer and an aliphatic diepoxy diluent crosslinked with a cycloaliphatic diamine were studied. These model networks have the characteristic that the crosslink density and the chain flexibility increase with the amount of diluent. These combined effects were studied by observing their mechanical properties. The decreases in the Young's modulus and the ultrasonic modulus were associated with the secondary thermomechanical relaxations that have been recorded and identified. Pre-plastic and plastic behaviors were discussed in terms of flexibility and crosslink density. A linear relationship was established between pre-plastic activation volume and crosslink density at temperatures lower than the activation of molecular chain motions responsible for the sub-Tg relaxations. At 0°C, a temperature above these secondary transitions, the higher the flexibility, the more defect nucleation and propagation increased. The work hardening rate and the upper yield stress decreased as the amount of diluent was increased. Fracture toughness was improved as the amount of diluent was increased. Crack propagation was related to the ability of the networks to deform plastically.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760312204
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  • 10
    Electronic Resource
    Electronic Resource
    Characterization of epoxy thermosetting systems by differential scanning calorimetry (1986)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 26 (1986), S. 1514-1523 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: Differential Scanning Calorimetry (DSC) is used to study the curing behavior of epoxy systems. For non-catalyzed diamine-epoxy systems, the reaction enthalpy ΔH and the glass transition temperature Tg are evaluated and related to the structure of the hardener. A method is developed to determine the activation energy. The effect of variations in the amine-to-epoxy ratio r on Tg is also examined. A maximum value is observed for r = 1. Then, the influence of benzyldimethylamine as catalyst in an anhydride/DGEBA system and in three diamine/DGEBA systems is reported. In the cases of DDS and DDA curing agent the maximum value of Tg is shifted, to r = 0, 6. The results are explained by different reaction mechanisms.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760262108
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