A Bio-based Rigid-flexible Polyester-Polycarbonate with Excellent Packaging Properties

Abstract

Using DMC derived from carbon dioxide (CO₂) to prepare polymers based on transesterification could reduce greenhouse gas emissions associated with polymer manufacturing and achieve sustainable production of polymers. However, the polymers prepared by this method exhibit deficiencies in thermal and mechanical properties, and the structure-property relationship of the resulting polymers needs to be elucidated. This study describes a new type of polyester-polycarbonates (PCCFs) based on biomass 2,5-furan dicarboxylic acid (FDCA). The series of copolyesters have acceptable glass transition temperature (47.13 °C < T_g < 75.63 °C) and high yield strength (46.13MPa < σ_y < 60.67 MPa). Time-temperature superposition (TTS) analysis shows that the characteristic relaxation time decreases with increasing carbonate content, resulting in a decrease in entanglement molecular weight, possessed a lower Kuhn monomer volume, and an increase in the number of entanglements per chain, suggesting a reduction in chain stiffness and entanglement density. Notably, PCCFs exhibit excellent packaging properties, especially gas barrier (P_CO2=0.0627 barrer and P_O2=0.0292 barrer) and optical properties (λ₄₀₀=86.28% and Haze=3.15%) for PCCF₃₀. In addition, the PCCF film has considerable shrinkage performance, with a shrinkage rate and shrinkage strain of 71.3% and 3.10 N mm^-1 respectively. It can also be chemically recycled with a monomer recovery rate of 87.2%, indicating good recyclability.