Internal Reorganization of Agglomerates as an Explanation of Energy Dissipation at Very Low Strain for Heterogeneous Polymer Systems

• Published in: Macromolecular theory and simulations 2012-02, Vol.21 (2), p.113-119
• Main Authors: Majesté, Jean-Charles, Carrot, Christian, Olalla, Beatriz, Fulchiron, René
• Format: Article
• Language: English
• Subjects: agglomerates; Applied sciences; Chemical Sciences; Composites; dynamic moduli; Exact sciences and technology; filled polymer; Forms of application and semi-finished materials; Material chemistry; oscillatory flow; Polymer industry, paints, wood; Polymers; Technology of polymers
• ISSN: 1022-1344; 1521-3919
• DOI: 10.1002/mats.201100063

The addition of a new mechanism to the Leonov model is described to capture the energy dissipation observed for highly filled systems even at very low strain values. By considering that flocs can undergo deformation before rupture, an internal reorganization within the agglomerates is introduced as a dissipative mechanism. The present improved model describes both oscillatory and strain sweep experimental results with only one additional, physically meaningful parameter: the number of hopping particles in the flocs which may be obtained from microscopic observations. Consistent values of this number are found in agreement with the histograms of the particle dispersion. In highly filled polymers melts, the observation of a secondary plateau on the loss modulus originates from the existence of agglomerates. The breaking of such objects causes dissipative processes characterized by a critical strain. Below this, experimental observations show that dissipation remains. This peculiar effect is attributed to internal re‐organization of agglomerates.