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Dynamic viscoelastic comparison of chemical and physical gels
Author(s) -
Yu Qun,
Amis Eric J.
Publication year - 1993
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19930760128
Subject(s) - viscoelasticity , gelatin , exponent , percolation (cognitive psychology) , dynamic mechanical analysis , dynamic modulus , scaling , materials science , transition point , modulus , thermodynamics , composite material , polymer , chemistry , physics , mathematics , biochemistry , linguistics , philosophy , geometry , neuroscience , biology
The dynamic viscoelastic behavior of TEOS (tetraethoxysilane) and gelatin during the sol‐gel transition is compared. Different profiles of dynamic storage modulus G″ and loss modulus G″ with time are seen. Gelation time tgel is determined from the frequency independent tan δ = G″/G' for both systems. During the period following the gelation point, a transition in the scaling exponent of G' with (t ‐ tgel) is seen. For TEOS, the exponent changes from 0.494 to 5.24; for gelatin, from 0.24 to 2.11. The percolation model is used to qualitatively explain the differences in different networks.