Enzyme-catalyzed synthesis of polyesters by step-growth polymerization : a promising approach towards a greener synthetic pathway

• Main Author: Nasr, Kifah
• Other Authors: Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie - CNRS Chimie (INC-CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université de Lille, Université de Mons, Jean-Marie Raquez, Philippe Zinck
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: HAL CCSD 2021
• Subjects: Enzymatic catalysis; Polyesters; Biobased polymers; Lipase; Furan; Levoglucosan; Catalyse enzymatique; Lévoglucosane; [CHIM.CATA]Chemical Sciences/Catalysis; Verte; Antarc*; Antarctica
• Online Access: https://theses.hal.science/tel-04221301; https://theses.hal.science/tel-04221301/document; https://theses.hal.science/tel-04221301/file/These_NASR_Kifah.pdf

Enzyme-catalyzed polymerization have been witnessing a growing attention in recent years as an eco-friendly substitute to metal-based catalysis. The objective of our work is to synthesize a series of polyesters via enzymatic catalysis based on different aliphatic and aromatic diols and diesters, where we focused on the influence of reaction parameters, monomer structures, and depicted the advantages and limitation of enzymatic catalysis in polymer synthesis. The enzyme used throughout our work was Novozym 435, a lipase from Candida antarctica, immobilized on an acrylic resin. In Chapter 1, we reviewed the different methods and approaches used in the literature to synthesize polymers via enzymatic catalysis. In Chapter 2, we performed the reaction between hexane-1,6-diol and diethyl adipate via a two-step polycondensation approach where we monitored the effect of certain parameters on the number average molecular weight (Mn). The influence of temperature, vacuum, and the amount of enzyme loading were determined using a central composite design. Other factors such as the reaction media, oligomerization time, and catalyst recyclability were also assessed. In Chapter 3 furan-based copolyesters were synthesized, where we showed that we can incorporate higher amounts of furan when using aliphatic diols with longer chains such as dodecane-1,12-diol. In Chapter 4, levoglucosan, an anhydrous 6-carbon ring structure and a pyrolysis product of carbohydrates such as starch and cellulose, was reacted against different chain length diesters in the presence of aliphatic diols and Novozym 435 as a catalyst. The polyesters produced were limited in their number average molecular weight (Mn) and the amount of levoglucosan that was successfully incorporated into the polymeric structure. Nevertheless, by increasing the chain length of the diester, we were able to produce a copolymer containing higher amounts of levoglucosan and a higher molecular weight. La polymérisation catalysée par des enzymes a fait l'objet d'une attention ...