Thermo-rheological effects on succesful 3D printing of biodegradable polyesters

Unformatted preprint version of the submitted articleBiodegradable polybutylene succinate (PBS) and poly (butylene succinate-ran-adipate) (PBSA) were characterized to find the thermo-rheological bases for 3D printing by Fused Filament Fabrication (FFF). In dynamic viscoelastic measurements, the samples fulfilled time-temperature superposition and Cox Merz rule. The viscosity results were linked to the excellent filaments obtained and the observed good flow in the printer nozzle. Using specific tearing experiments, outstanding welding of the printed layers was obtained. Results were discussed considering the values of the entanglements density obtained by SAOS measurements. The main difference between both polymers was observed in the final production of 3D printed parts because the high crystallinity of PBS produced significant warpage, which prevented its use for practical purposes. On the contrary, the less crystalline PBSA random copolymer showed excellent performance during FFF. Thus, dimensionally stable and ductile printed objects were obtained, opening new processing routes for semi-crystalline biodegradable polyesters.This work has received funding from the European Union´s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 778092, from MINECO, project: MAT2017-83014-C2-1-P and from the Basque Government through grant IT1309-19