In this dissertation we investigate experimentally the linear dynamics and nonlinear shear response
of macromolecular networks with ultimate aim to understand the conditions for reinforcement,
yielding and flow due to combined constraints of topology and attractive interactions, and
eventually come up with design criteria for materials with improved properties. From established
to novel model systems, we utilize linear oscillatory and nonlinear steady shear rheology, creep
and TMA tube-based modeling in order to understand how architecture, topology, physical and
chemical crosslinks influence the performance of networks. This thesis is divided into three main
sections. The first discusses the relaxation mechanisms of simple topologically constrained
entangled homopolymers with emphasis on stress relaxation upon cessation of steady shear flow.
The second and third sections focus on the development of multi-responsive polymeric networks
containing at least two distinct dynamic modes. In particular, the second part investigates the role
of the macromolecular architecture and the number of physical bonds on the rheological properties
of metal-ligand supramolecular networks. The last part addresses the effects of nanofiller internal
microstructure, size and volume fraction on network reinforcement containing single chain
nanoparticles.
(EN)
University of Crete
