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Faculté des Sciences
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MASTER THESIS
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Mémoire, Partim B

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Gillissen, Emeline ULiège
Promotor(s) : Detrembleur, Christophe ULiège
Date of defense : 22-Jan-2024 • Permalink : http://hdl.handle.net/2268.2/20024
Details
Title : Mémoire, Partim B
Author : Gillissen, Emeline ULiège
Date of defense  : 22-Jan-2024
Advisor(s) : Detrembleur, Christophe ULiège
Committee's member(s) : Grignard, Bruno ULiège
Bourguignon, Maxime ULiège
Naveau, Elodie ULiège
Language : English
Number of pages : 77
Discipline(s) : Physical, chemical, mathematical & earth Sciences > Chemistry
Research unit : Center for Education and Research on Macromolecules (CERM)
Institution(s) : Université de Liège, Liège, Belgique
Degree: Master en sciences chimiques, à finalité spécialisée
Faculty: Master thesis of the Faculté des Sciences

Abstract

[en] CO2 self-blowing polyhydroxyurethane (PHU) foams are emerging alternatives to conventional
polyurethane (PU) foams made of harmful isocyanates. It is thus crucial to assess their
recyclability. Therefore, this master thesis aims to elaborate a foam-to-foam recycling
methodology of end-of-life PHUs leveraging from their inherent reprocessability, even for
thermosets thanks to the dynamicity of hydroxyurethane linkages, and using supercritical CO2
(scCO2) as physical blowing agent. Initial experiments highlighted significant challenges in
reprocessing PHUs into thick films and their refoaming due to the high density and crosslinking
density of reprocessed material. Thus, two strategies were developed to overcome these hurdles.
First, grinded PHU foams have been exploited as fillers within PCL, a polymer easily foamed
by scCO2. Such approach rendered PCL foams, with PHU acting as a structural reinforcement
component. The second strategy focused on the engineering of new PHU formulations
delivering samples featuring dual dynamic bonds (disulfide and hydroxyurethane). We
postulated that the presence of disulfides, introduced within PHUs by utilizing biobased
cystamine, should facilitate both the reprocessing of PHU foams into films as well as their
scCO2 refoaming via temporary de-crosslinking. The dynamicity of the disulfide linkages was
further studied by stress-relaxation studies which highlighted a correlation between the
relaxation of the material and the temperature/cystamine content, alongside with the discovery
of a water-dependent relaxation. However, while disulfide bonds facilitated the reprocessing of
PHUs into films, their refoaming remained a major obstacle probably due to insufficient de crosslinking of PHUs during the impregnation and/or expansion step but also due to low CO2
solubility within the PHU matrix prior refoaming.


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Author

  • Gillissen, Emeline ULiège Université de Liège > Master en sc. chimiques, fin. spéc.

Promotor(s)

Committee's member(s)

  • Grignard, Bruno ULiège Université de Liège - ULiège > Département de chimie (sciences) > Centre d'études et de rech. sur les macromolécules (CERM)
    ORBi View his publications on ORBi
  • Bourguignon, Maxime ULiège Université de Liège - ULiège > Département de chimie (sciences) > Centre d'études et de rech. sur les macromolécules (CERM)
    ORBi View his publications on ORBi
  • Naveau, Elodie ULiège Université de Liège - ULiège > Département de physique > Département de physique
    ORBi View his publications on ORBi
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