Structural and property modulation of cyclohexanedimethanol-based polycarbonates by bio-based tetrahydrofuran dimethanol with cyclic ether structures

1, 4-cyclohexanedimethanol-based polycarbonates have desired thermodynamic property yet poor degradation capability. Introducing aliphatic units into the molecular chains could effectively improve the degradability at the severe expense of thermodynamic properties. For this reason, biobased 2, 5-tetrahydrofurandimethanol (THFDM) with cyclic ether rigidity was selected as the modification unit and poly(1, 4-cyclohexyldimethylene-co-2,5-tetrahydrofurandimethanol carbonate) (PCThC) copolymers with higher molecular weights were synthesized via melt ester exchange polycondensation method. The composition and microstructure were investigated by NMR, which confirmed the random distribution among the copolymer components. DSC and WAXD results reveals that the introduction of THFDM units break the regular arrangement of the molecular chains in PCThCs, reduce the crystallisation ability, which promote the transition from the semi-crystalline to amorphous. Furthermore, the rigid ring structure in THFDM prevents the rapid declination of glass transition temperature (T_g) and keeps the good thermal stability. The ring structure in the THFDM endow higher stiffness and better mechanical performance for the polymer. The ether bonds in THFDM enhance the hydrophilicity of the PCThC copolymers, resulting in a gradual acceleration of the hydrolysis rate. The copolymers exhibit pleasant degradation ability either under acidic or alkaline environment.