Počet záznamů: 1

Diluent induced cyclization and phase separation in polymer networks

  1. 1.
    0366161 - UMCH-V 2012 RIV DE eng J - Článek v odborném periodiku
    Dušková-Smrčková, Miroslava - Valentová, H. - Ďuračková, Andrea - Dušek, Karel
    Diluent induced cyclization and phase separation in polymer networks.
    Macromolecular Symposia. 306-307, č. 1 (2011), s. 67-76 ISSN 1022-1360.
    [Polymer Networks Group Meeting /20./. Goslar, 29.08.2010-02.09.2010]
    Grant CEP: GA ČR GA106/08/1409
    Výzkumný záměr: CEZ:AV0Z40500505
    Klíčová slova: cyclization * elasticity * gelation
    Kód oboru RIV: JI - Kompozitní materiály

    The effect of the presence of diluent during network formation on the gel-point conversion, αcrit, and on the equilibrium elastic modulus was studied using polyurethane networks from star-shaped polyols and a star-shaped triisocyanate.The dependence of αcrit on reciprocal concentration of functional groups,1/c0, extrapolated well for 1/c0—›0 to the value calculated corresponding to the ring-free system.The decrease of the equilibrium modulus and the concentration of elastically active network chains (EANC) in dependence on the volume fraction of polymerizable compounds (solids).The continuous change of gel volume as a result of phase separation was obtained by solving an integral equation respecting the thermodynamic stability of the system.The change of the concentration of EANCs obtained from equilibrium modulus was translated into the intermolecular conversion calculated using the branching theory. Intermolecular conversion depended linearly on the shift of the gel-point conversion.
    Trvalý link: http://hdl.handle.net/11104/0201235