Innovative design of covalent adaptable polymer networks: Chemistry of new catalysts for bond exchange reactions and strategies towards controlled and efficient self-healing

Walter Alabiso

Research output: ThesisDoctoral Thesis

Abstract

In rapidly evolving fields such as self-healing polymers, keeping up to date with the state of the art is key. The growth of this ever-expanding class of materials has an impact on modern engineering and technology, as they bring about a reduction in costs and risks in applications, along with an extended life span and sustainability of the designed parts. The research work covered in this dissertation was carried out with a twofold goal: (1) to develop cutting-edge strategies to expand the horizon of self-healing polymers and (2) to benchmark them against the most recent scientific and industrial advancements in literature. Within this work, a study targeted at introducing new catalysts for bond exchange (namely, organic phosphates and phosphonates for transesterification) in thiol-click photopolymers has been explored. As a result of this advancement, a versatile toolkit of readily available compounds was provided for further research. An organic methacrylic phosphate was then selected to catalyse thermo-activated transesterification in synergy with shape memory effect to boost the healing of large defects (50–150 µm) in thiol-acrylate films. Another highlight reported in this dissertation is the unprecedented use of chemical amplification as a tool for the spatio-temporally resolved activation of dynamic bond exchanges in orthogonally cured thiol-click photopolymers. This approach hinged upon the use of photo-latent acids (a covalently blocked p-toluenesulfonic acid and a sulfonium-based photoacid generator) to trigger the release of hydroxy groups for the subsequent transesterification reactions, thus switching on-demand from a static to a dynamic network. To validate the principle, a comprehensive study of the reaction kinetics, thermomechanical properties and stress relaxation behaviour of the resulting polymers has been conducted. In conclusion, the scientific endeavours herein collected represent an important step in the direction of advanced self-healing polymers. This is but a small contribution to the solution of the open-ended challenges in the field, which still attract and motivate polymer chemists.
Translated title of the contributionInnovatives Design kovalent anpassungsfähiger Polymernetzwerke: Chemie neuer Katalysatoren für Bindungsaustauschreaktionen und Strategien zur kontrollierten und effizienten Selbstheilung
Original languageEnglish
QualificationDr.mont.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Kern, Wolfgang, Assessor A (internal)
  • Bongiovanni, Roberta, Assessor B (external), External person
  • Griesser, Thomas, Co-Supervisor (internal)
  • Schlögl, Sandra, Supervisor (internal)
DOIs
Publication statusPublished - 2023

Bibliographical note

embargoed until 03-10-2028

Keywords

  • Dynamic covalent networks
  • Vitrimers
  • Self-healing polymers
  • Transesterification
  • Polymer Chemistry
  • Catalysts

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