Functional and degradable copolyesters by ring-opening copolymerization of epoxides and anhydrides. (19th January 2023)

• Record Type: Journal Article
• Authors: Hirschmann, Max; Andriani, Fika; Fuoco, Tiziana
• Is Part Of: European polymer journal. Volume 183(2023)
• Publication Date: 2023-01-19
• Subjects: Ring-opening copolymerization -- Aliphatic and semiaromatic copolyesters -- Unsaturated epoxide -- Organic anhydrides -- Cross-linking -- Degradation; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; Polymerization; Polymers; Periodicals; Electronic journals; 547.705
• DOI: 10.1016/j.eurpolymj.2022.111766
• Languages: English
• ISSNs: 0014-3057

Abstract

Graphical abstract: Highlights: A mixture of two epoxides is copolymerized with each of four structurally diverse cyclic anhydrides. The organocatalytic, chemoselective strategy affords functional and fully alternating copolyesters. The anhydride structure dictates the macromolecular and thermal properties of the polymers. Copolyesters degrade in both abiotic and enzymatic hydrolytic conditions. Abstract: The ring-opening copolymerization (RO co P) of epoxides and anhydrides is exploited to afford 4 structurally diverse and functional copolyesters. Mixtures of 2 epoxides (allyl glycidyl ether and butylene oxide) with 1 anhydride (succinic, glutaric, phthalic and homo phthalic anhydride) are copolymerized in the presence of bis(triphenylphosphine)iminium chloride (PPNCl) as organocatalyst. All monomer combinations yield vinyl-functionalized materials with alternating epoxide-anhydride units, statistical incorporation of both epoxides along the polymer chain and molar masses up to 28.3 kg/mol. The copolyesters are amorphous with a T g between –39 °C and 38 °C. Together with the molar mass, the anhydride dictates the thermal stability of the copolyesters with glutaric anhydride resulting in a remarkably high thermal stability up to 310 °C. In a post-polymerization step, the pendant double bonds are radically crosslinked to gels with swelling ratios above 1500 % and comparable to enhanced thermal stability with respect to the non-crosslinked, parent copolyesters. The degradation of the 4 copolyesters (before and after crosslinking) is tested in abiotic and enzymatic conditions: The highest degradation rates are observed for the non-crosslinked materials in enzymatic conditions with a mass loss of up to 60 % after 27 d. After crosslinking, the gels are more stable against degradation under both conditions, although a decrease in the gel content and a decrease in mass indicates that degradation still takes place.