Design and characterization of actively-moving polymers obtained via dual-curing processing

Identifier:  TDX:3328

Handle: https://hdl.handle.net/20.500.11797/TDX3328

Authors:  Belmonte Parra, Alberto Francisco

Abstract:
In this doctoral thesis it has been carried out the synthesis, characterization and modelling of the so-called Actively-moving Polymers or polymers that respond to external stimuli with dimensional changes. On the one side, epoxy-based shape-memory polymers have been synthesised and characterized with thiol compounds via “click” reactions and dual-curing processing. The effect of the network structural properties, network relaxation, thermomechanical properties and programming conditions with the shape-memory performance has been studied. For this purpose, dynamic-mechanical, thermomechanical, rheological and calorimetric analyses, as well as shape-memory cycling have been performed. On the other side, epoxy-based liquid-crystalline networks with shape-changing properties have been synthesised and characterized using dicarboxylic acids. In this case, besides the network structural and thermomechanical properties, the liquid-crystalline properties have been related with the shape-changing performance. To this end, shape-changing cycling under different stress levels and experimental conditions have been carried out. Finally, the epoxy-based polymers obtained via dual-curing processing and the liquid-crystalline networks have been combined to design free-standing actuators, that is, actuators capable to reversibly change their shape upon thermal stimulation. Different actuators configuration have been designed and the level and velocity of actuation under different heating-cooling conditions have been studied.