Preparation of Copolyester <scp>PESG</scp> and Its Properties by <scp>CHDM</scp> Modified <scp>PES</scp>

ABSTRACT This paper introduces different contents (0–20 mol%) of the third monomer 1,4‐cyclohexanedimethanol (CHDM) into the coupling reaction system of ethylene carbonate (EC) and dimethyl succinate (DMSu) to synthesize polyethylene succinate (PES) copolyester (PESG), aiming to disrupt the regularity of the PES molecular chain structure, reduce its crystallization ability, and improve its brittleness. The novelty lies in the use of this novel reaction system that not only enhances the toughness of the copolyester by disrupting its crystallinity, but also allows for the green co‐production of DMC while maintaining biodegradability. The results of Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance ( 1 H‐NMR), and gel permeation chromatography (GPC) tests indicate that the molecular backbone of the PESG sample contains two types of repeating structural units, and the molecular weight meets the expected standard. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and X‐ray diffraction (XRD) showed that the thermal decomposition temperature of PESG was above 380°C, and the melting temperature decreased, and the crystallization ability weakened. Mechanical and degradation tests showed that the toughness of PESG was improved and had good degradation performance. The modified copolyester shows significant potential for applications in packaging materials and biodegradable films, making it a promising material for sustainable applications.