Efficient Synthesis of Itaconate Polyesters with Amine-Triggered Rapid Degradation and Outstanding Mechanical Properties: An Experimental and Theoretical Study on Degradation Mechanisms

Abstract

A range of degradable polyesters have been developed as sustainable alternatives for commercial plastics; however, limitations of composting facilities and uncontrolled degradation in the environment hindered their viability. In this study, biobased itaconic acid was selected as an active site to control the degradation of polyesters. A series of PBXI copolyesters with M w 's ranging from 4.86 to 8.31 × 10 4 g/mol and high intrinsic viscosities of more than 1.15 dL/g were successfully synthesized without any crosslinking by selecting appropriate reaction conditions, including condensation temperature and vacuum, effective inhibitor, and catalyst. The obtained copolyesters were semicrystalline, and their T m 's could be regulated from 42.5 to 179.5 °C. They exhibited outstanding elastic modulus (120−598 MPa) and tensile strength (17.9−51.4 MPa) among degradable polymers. Degradation experiments demonstrated that the incorporation of itaconate segments could facilitate both the hydrolysis and enzymatic degradation of polyesters. The state-of-the-art computation and analysis via molecular dynamics (MD) simulations of PBXI−CALB complexes elucidated the enzymatic degradation mechanism. Experimental results proved that, at room temperature, the degradation could be stimulated and regulated by amines without a catalyst and the M n 's of lactamization products rapidly decreased to less than 5000 g/mol within 24 h. Moreover, the copolymerized structure of copolyesters and solvent factors could influence the aza-Michael addition between amines and itaconate units. This work provides a strategy to synthesize biodegradable copolymers with the potential to undergo controlled and rapid in vivo degradation with outstanding mechanical properties.

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

“…Fumarates possess higher energy stability of CC, but they are still suitable for Michael addition reaction with nucleophiles . Our design was also influenced by polymers from maleic acid or itaconic acid, which undergo chain cleavage through Michael addition and intramolecular cyclization. , …”

“…67 Our design was also influenced by polymers from maleic acid or itaconic acid, which undergo chain cleavage through Michael addition and intramolecular cyclization. 25,41 Modification of PBFFu40 with L-Cysteine methyl ester hydrochloride was conducted first. Heat treatment of PBFFu40-P1 samples was performed from 40 to 90 °C with 10 °C of interval.…”

“…Double-bond of unsaturated monomers (FA or itaconic acid, for instance) provide functionalized active sites, expected to tune polymers degradation kinetics and profiles in a robust and controllable way depending on the targeted application. In our previous work, itaconate-based polyesters could be functionalized through the aza-Michael addition of primary amines, followed by a lactamization step to polyester chain scission . The degradation process is usually chemically regulated, such as hydrolysis under enzymatic, acidic, basic, or neutral conditions, or through acid-degraded spiroacetal units. , Moreover, physical techniques, involving ultrasound fragmentation, − heat treatment, mechanophore installation, as well as through exposure to electromagnetic radiations, , can help control polymer degradation in a more convenient way.…”

High-Molecular-Weight and Light-Colored Disulfide-Bond-Embedded Polyesters: Accelerated Hydrolysis Triggered by Redox Responsiveness

“…In previous works, we demonstrated the control of fast degradation by amine-triggered Michael addition and the ensuing lactamization of itaconic acid-based polyesters. 9 degradable reversible imine bonds were conducive to building a class of doubly degradable polymers. 10 Among the labile bonds, 11−13 such as imine, hydrazone, 14 acetal, disulfide, and ortho ester, disulfide linkages have been applied broadly in reduction-responsive systems.…”

“…In previous works, we demonstrated the control of fast degradation by amine-triggered Michael addition and the ensuing lactamization of itaconic acid-based polyesters . Fukuda et al introduced imine bonds into PBS by the chain extension reaction of isocyanate groups.…”