| Autor: |
Bershtein, V.A., Egorov, V.M., Yakushev, P.N., David, L., Fainleib, A.M., Grigorieva, O.P., Bei, I., Kripotou, S., Pissis, P. |
| Předmět: |
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| Zdroj: |
Journal of Macromolecular Science: Physics; Jan2007, Vol. 46 Issue 1, p207-230, 24p, 1 Diagram, 2 Charts, 14 Graphs |
| Abstrakt: |
Structure and dynamics over the range from -150 to 300°C were studied in a series of polycyanurate-poly(tetramethylene glycol) (PCN-PTMG) hybrid networks. Wide-angle x-ray diffraction (WAXD), small-angle x-ray scattering (SAXS), laser-interferometric creep rate spectroscopy (CRS), differential scanning calorimetry (DSC), and thermally stimulated depolarization currents (TSDC) techniques were applied. The networks were synthesized from the dicyanate ester of bisphenol A (DCEBA) and hydroxyl-terminated PTMG with Mn=1000, 2000 or 5000 g/mol and weight fraction of 10, 20, 30, and 40%. The noncrystalline structure and the pronounced structural nanoheterogeneity, depending on PTMG chain length and PCN-PTMG ratio in the hybrid systems, were evidenced. Combined CRS/DSC analysis revealed a complex dynamics in these networks, in particular a dispersion of glass transitions in a wide temperature range. On this basis, the presence of nanodomains with different degrees of rigid cross-linking (XCN→PCN), i.e., compositional nanoheterogeneity in these hybrids was shown. The results obtained turned out to be of applied interest because of a substantial increase in tensile strength because of arising microplasticity at low temperatures, and retaining some creep resistance, at low stresses, up to temperatures much higher the basic Tg. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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