Design of renewable and functional polyamides and polyhydroxyurethanes with tunable structure-property relationships
Time: Fri 2021-12-10 10.00
Location: F3, Lindstedtsvägen 26, Stockholm
Video link: https://kth-se.zoom.us/j/62270797340
Language: English
Subject area: Fibre and Polymer Science
Doctoral student: PhD student Charalampos Pronoitis , Polymerteknologi
Opponent: Privatdozent Stefan Naumann, University of Stuttgart
Supervisor: Associate Professor Karin Odelius, Polymerteknologi; Professor Minna Hakkarainen, Fiber- och polymerteknologi, Polymerteknologi, Wallenberg Wood Science Center, Polymerteknologi
QC 2021-11-03
Abstract
Redesigning polymeric materials and rethinking their use is imperative in the prospect of a more sustainable future. Critical aspects in this endeavor are the use of renewable monomers to decrease the environmental footprint, implementing green syntheses and production processes and the design for increased recyclability as an end-of-life option to diverge from the generation of plastic waste. In this thesis, polyamides and polyhydroxyurethanes were synthesized employing biobased and structurally diverse monomers. Through ring-opening aminolysis and ring-opening polymerization, solvent- and toxic reagent-free, atom-economical and energy efficient systems could be realized. Ethylene brassylate, a fatty acid-derived macrodilactone, was employed for the synthesis of permanent and dynamic polyamide networks, carried out in a single step and under mild temperature, by leveraging the inherent properties of the monomer. Carbon dioxide and its derivatives were explored for the preparation of diverse cyclic carbonates serving as precursors to dynamic polyhydroxyurethane networks and copolymers with complex architecture. The permanent polyamide networks were semicrystalline and exhibited a shape-memory effect with high fixicity and recovery ratio. The dynamic polyamide and polyhydroxyurethane networks were realized by a common strategy that introduced exchangeable disulfide bonds into them. The networks were reprocessable from one to three cycles after damage, and a profile of properties (thermal, mechanical, viscoelastic and dynamic) was achieved by varying the crosslink density and the structure of the monomers used. A linear polyhydroxyurethane was carefully designed to enable its dissolution in ε-Caprolactone, which under appropriate conditions, facilitated its solvent-free ring-opening polymerization from the pendent hydroxy groups of the polymer. The resulting graft copolymers had tunable molar mass and the system was not limited by the bulk polymerization conditions.