Investigation of structure-properties relationship of modified green PBS-DLS copolymers and their processability by 3D printing

Abstract

In this study, the synthesis and physico-chemical properties of sustainable poly(butylene succinate-dilinoleic succinate) (PBS-DLS) copolymers modified with hydrophilic poly(ethylene glycol)(PEG) are discussed in context of structure-properties relationship of polymeric materials and their processibility. The copolymers of variable segmental composition and containing green monomers such as succinic acid and dilinoleic diol, were successfully synthesized by non-solvent two-step transesterification and polycondensation reaction. Synthesized polymers were collected as crystallized filaments directly from the reactor. These filaments were used without any postprocessing for 3D printing. Characterization of chemical structure confirmed the presence of functional ester and ether groups. Crystallized copolymers revealed spherulitic morphology and phase transitions which were dependent from the segmental composition. 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 in comparison to copolymers containing 60 wt% of PBS hard segments. The mechanical properties and printability of the copolymers depended also on their segmental composition, where higher hard segment content (70 wt%) facilitated better printability compared to polymers containing 60 wt% of PBS hard segments. Additionally, we demonstrate that new copolymers were suitable for electrospinning yielding nanofibers of average fiber diameters between 400 and 600 nm. The obtained results showed excellent processability, rubber-like elasticity and improved hydrophilicity of new polymers thus indicating that segmental composition can be important design parameter in preparation of new green copolymers for advanced processing by 3D printing and electrospinning.