Dual-curing thiol-acrylate-epoxy thermosets for functional applications

Identifier:  TDX:3218

Handle: https://hdl.handle.net/20.500.11797/TDX3218

Authors:  Russo, Claudio

Abstract:
Nowadays, more and more applications demand materials with complex shape designs which is a difficult task when working with thermosetting polymers. Dual-curing processing is an extremely valuable tool for thermosets design. It consists in the combination of two sequential of simultaneous crosslinking process. The benefits of dual-curing processing rely on its processing flexibility and the properties enhancement of cured parts by single- or multi-stage scenarios. In this work, we developed a novel dual-curing system based on two “click” reactions: the thiol-acrylate Michael addition (first stage) and thiol-epoxy reaction (second stage). Exploiting the developed system, dual-curing processing was proved to have high potentiality in adhesive bonding application, allowing accurate dimensional control of the adhesive layer and higher adhesive strength than on-step curing. Finally, thiol-acrylate-epoxy dual-curing system was used to develop electroresponsive shape-memory polymers. The electroresponsive ability was obtained incorporating an electrically conductive layer into a thiol-acrylate-epoxy shape-memory polymer taking advantage of the dual-processing. In this design, the direct heating from external sources (i.e., oven) is replaced by a more efficient internal Joule heating produced in the conductive layer when an controlled voltage is applied. The electro activation of the SME resulted in significantly faster recovery and, using a custom-made thermoelectric control, a precise control of the recovery process was achieved