The effect of segmental composition of bio-based PBS-DLS-PEG copolymers on their physico-chemical properties and processability by 3D printing and electrospinning

In this study, the synthesis and physico-chemical properties of poly(butylene succinate-dilinoleic succinate-ethylene glycol succinate) (PBS-DLS-PEG) copolymers differing in segmental composition are discussed in order to determine their structure-properties relationship and translate it to their electrospinability and 3-D printability. The copolymers, containing sustainable monomers such as succinic acid and dilinoleic diol, were successfully synthesized by two-step transesterification and polycondensation, and collected directly from the reactor as crystallized filaments suitable for 3D printing. Chemical characterization indicated the formation of expected functional ester groups. Crystallized copolymers revealed spherulitic morphology and phase transitions typical for thermoplastic elastomers. Interestingly, incorporation of 5 wt% PEG into copolymers containing higher hard segments content (70 wt%) disturbed the banded spherulitic morphology of copolymers, contributed to the increase of elasticity up to 830%, and reduced the water contact angle indicating improvement of copolymers hydrophilicity. The mechanical properties and printability of the copolymers depended on their segmental composition, with higher hard segment content facilitating good printability. In solution processing, the copolymers turned into nanofibers via electrospinning with average fiber diameters between 400 and 600 nm. The obtained results showed excellent melt and solution processability, rubber-like elasticity and tailored physical characteristics dependent from segmental composition of the new sustainable PBS-DLS-PEG copolymers.