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Problems of structural characterization of polymer networks
Author(s) -
Dušek Karel,
Ilavský Michal
Publication year - 1979
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760190404
Subject(s) - modulus , characterization (materials science) , materials science , relaxation (psychology) , cluster analysis , network formation , network structure , polymer , reactivity (psychology) , thermodynamics , stress relaxation , constant (computer programming) , chemical physics , biological system , composite material , computer science , mathematics , nanotechnology , chemistry , combinatorics , physics , theoretical computer science , artificial intelligence , medicine , psychology , social psychology , creep , alternative medicine , pathology , programming language , biology
Problems of the characterization of network structure by investigating the network formation and its response to mechanical stress have been analyzed. Attention has been devoted to the effect of reactivity of functional groups and cyclization on the formation of network structure and to problems of obtaining the equilibrium modulus and its relation to the concentration of elastically active network chains (EANCs). It has been demonstrated that a theoretical description of network formation must be based on reliable information on the rules of joining of functional groups and on their relative reactivity; the tree‐like approximation offers a number of structural parameters of the sol and gel including, e.g, chemical clustering of units of a certain type. The main obstacles to reaching the equilibrium modulus are long relaxation, times of lightly crosslinked networks and the occurrence of secondary relaxations. In correlating the equilibrium modulus and the concentration of EANCs, it is necessary to find conditions under which the Mooney‐Rivlin constant C 2 can be neglected and to carry out the required corrections of the modulus, if experimental conditions differ from those of network formation.