Coexistence of Isodimorphism, Isomorphism, and Comonomer Exclusion within a Single Family of Poly(butylene- ran -octamethylene carbonate) Random Copolymers

作者：Xinyu Liu, Yilong Liao, Ricardo A. Pérez‐Camargo, Zhe Ma, Alejandro J. Müller · 发表于：Macromolecules · 年份：2025 · DOI：10.1021/acs.macromol.5c02276 · 被引用次数：6 · 研究领域：Carbon dioxide utilization in catalysis、biodegradable polymer synthesis and properties、Polymer composites and self-healing

In this study, a series of new random poly(butylene- ran -octamethylene carbonate) (PB x O y C) copolymers was synthesized via melt polycondensation, spanning the entire 0–100% range of butylene carbonate (BC) fraction ( f BC ), in 10% increments. Their crystallization behavior was examined in detail. Differential scanning calorimetry (DSC) characterization showed a pseudoeutectic-like behavior, where both melting and crystallization temperatures decreased to a minimum at f BC = 53 mol %. As f BC was further increased, copolymer crystallization was completely suppressed for f BC = 66–75 mol % and then reappeared at f BC = 87 mol %, suggesting a transition from isodimorphism to complete comonomer exclusion in the composition range where only poly(butylene carbonate) (PBC) could crystallize. Additionally, Wide Angle X-ray Diffraction (WAXD) and Fourier Transform Infrared Spectroscopy (FTIR) were used to analyze the composition-dependent crystalline structures. It was found that copolymers with low BC content, f BC ≤ 19 mol %, crystallized into poly(octamethylene carbonate) (POC) crystals, while those with high BC content, f BC ≥ 87 mol %, produced PBC crystals. However, within the intermediate composition range ( f BC = 25–53 mol %), a γ phase was formed, with a crystalline structure distinct from those of the parent components and their polymorphic forms. WAXD results suggest that this γ phase results from the cocrystallization of both BC and OC units (i.e., isomorphic crystal...