Tunable Thermal-Induced Degradation in Fully Bio-Based Copolyesters with Enhanced Mechanical and Water Barrier Properties

Bio-based fumaric acid act as a keymonomer for the fabricationof high-performance and thermal-induced degradation polymers. Obtainedpoly(butylene 2,5-furandicarboxylate/fumarate) copolyesters had ahigh number-average molecular weight from 27,500 to 37,600 g/mol.Trans C UC bonds and the conjugated effect provide interestingproperties. Influenced by the thermal history, the elastic modulusand tensile strength (>50 MPa) are much higher than PBAT. TransC UCbonds of fumaric acid and intermolecular interactions of furan ringsrestrict the diffusion of gas and water molecules. Specifically, thewater barrier is 4-12 times better than PBAT, filling the gapin biodegradable food packaging. The hydrolysis resistance of fumaratesegments provides good durability during their life span. The functionalizationof PBFFu by thiol-Michael addition was performed at room temperature.Three substituent groups bring different conditions of pendant aminogroups, resulting in the thermal-induced intramolecular cyclizationfrom 40 to 100 & DEG;C. Fumaric acid could be a critical point toachieve the coordination of high-performance and temperature-induceddegradation.