Development of environmentally friendly polymerization processes

• Main Authors: Gkountela, Christina, Γκουντέλα, Χριστίνα
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: National Technical University of Athens (NTUA) 2023
• Subjects: Βιοκατάλυση; Πολυ(ηλεκτρικός βουτυλεστέρας); Πολυ(φουρανοδιικός βουτυλεστέρας); Μεταπολυμερισμός; ΠΣΚ; Εγκλεισμός; Biocatalysis; Poly(butylene succinate); Poly(butylene 2,5-furandicarboxylate); Post-polymerization; SSP; Encapsulation; Επιστήμη Χημικού Μηχανικού; Επιστήμες Μηχανικού και Τεχνολογία; Χημική μηχανική; Chemical Engineering; Engineering and Technology; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/10442/hedi/55334; https://doi.org/10.12681/eadd/55334

Given the fossil fuel crisis and the steady consumption of finite resources, green polymers are becoming necessary. The term “green” describes materials that present green properties (such as biological origin and/or biodegradability) and are produced via sustainable processes conducted under mild conditions and not requiring chemical catalysts or toxic solvents. Truly green materials must combine these characteristics; consequently, enzymatically synthesized bio-based and/or biodegradable polymers can be characterized as truly green. The main scope of this research work was to produce the bio-based polymers poly(butylene succinate) (PBS) and poly(butylene 2,5-furandicarboxylate) (PBF) in a sustainable route, i.e., enzymatic prepolymerization combined with low-temperature post-polymerization. In addition to their sustainability, other characteristics we aim for in these materials include high purity in terms of metal catalyst residues and side reactions’ by-products and controlled molecular weight. In this way, we create materials of increased research and industrial interest suitable for use in demanding applications such as high-purity encapsulation systems (e.g., in the food packaging and biomedical sector).Enzymatic polymerization was conducted, and the immobilized Candida antarctica Lipase B was used as a biocatalyst in solvent-free systems to produce PBS and PBF via two-stage processes. The first step was conducted under milder conditions compared to chemical routes (40 or 50°C, atmospheric pressure, 24 h) to minimize possible monomers’ losses. The second stage’s conditions (reaction temperature, pressure, time) were thoroughly investigated. Based on the reaction temperature investigation, conducted under 200 mbar, 90°C was indicated as the optimum temperature for both PBS and PBF. The reduced pressure (20 mbar) slightly increased the molecular weight (MW) of PBS, reaching the values of 2500 and 6700 g/mol (Mn and Mw, respectively) and did not affect the MW of PBF, remaining 1800 and 1900 g/mol. The ...