Messanae Universitas Studiorum

Dynamics of segmental relaxations for cyanurate-containing semi-interpenetrating polymer networks

Bartolotta, Antonio and Di Marco, Gaetano and Farsaci, Francesco (2001) Dynamics of segmental relaxations for cyanurate-containing semi-interpenetrating polymer networks. Accademia Peloritana dei Pericolanti - Classe di Scienze FF.MM.NN., 78-79 (1). pp. 131-146.

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    Abstract

    Two series of semi-interpenetrating polymer networks (semi-IPNs) of the same linear polyurethane (LPU) and two different heterocyclic polymer networks (HPN-1 and HPN-2) based on thermally cured dicyanic ether of Bisphenol-A, were characterized by differential scanning calorimetry (DSC), complex dynamic modulus E* = E' + iE" and mechanical loss tangent (tan $\delta$ = E"/E', where E' and E" are the storage and loss components of the loss modulus, respectively). The temerature dependence of $\alpha_a$ and $\gamma$ relaxations were studied as a function of HPNs content. By the experimental results no large-scale structural heterogeneities were detected in sample with HPN-1. It has been observed that the inclusion of LPU softens both the HPN-1 and HPN-2 rigid networks which, on the contrary, affects the LPU chain motion by restricting the cooperative long-range segmental dynamics. Single glass transitions are observed in semi-IPN-1 which indicate an affinity between LPU and HPN-1 and also a large scale structural homogeneity.
    Differently from semi-IPN-1, two glass transitions are observed in semi-IPN-2, where the absence of chemical intermolecular interactions is thought to give rise to a double phase amorphous network, each phase preserving the main morphological characteristics of the pure components.

    Keywords: Anelasticity; Internal friction; Anharmonicity

    Pacs index: 61.40 km or 62.40+i

    Item Type: Article
    Subjects: M.U.S. - Miscellanea > Atti Accademia Peloritana > Classe di Scienze Fisiche, Matematiche e Naturali > 2000-01
    Divisions: UNSPECIFIED
    Depositing User: Dr PP C
    Date Deposited: 19 Sep 2012 10:41
    Last Modified: 19 Sep 2012 10:41
    URI: http://cab.unime.it/mus/id/eprint/671

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