The importance of biodegradable polymers has increased as the environmental pollution caused by the use of plastics in recent years, and the possibility of using biodegradable polymers for various medical purposes such as sutures, wound dressings, tissue regeneration, and artificial organs has generated commercial and academic interest. Biodegradable polymers generally have a polyester structure such as polycaprolactone (PCL), stereoisomers of polylactic acid (PLA), polyhydroxybutyrate (PHB) and polybutylene succinate (PBS), and their ester bonds in the polymer are hydrolyzed with carboxyl groups and hydroxyl groups to cause decomposition. The 3D-printing technology that uses biodegradable polymers as bio-inks can create products quickly and easily in a desired shape, and has the advantage of being able to use it in the medical field, especially in the production of scaffolds with fine structures or personalized artificial organs.
Biodegradable polymers used for medical purposes need to adjust their physical properties and degree of biodegradation according to the application. Therefore, in this study, the physical properties and biodegradability of bio-elastomers were adjusted by controlling the polymer structure, and 3D-printing was performed using the synthesized bio-elastomer. Polyethylene glycol (PEG), polycaprolactone (PCL), and polylactic acid (PLA) were used as biocompatible and biodegradable materials. By controlling the PEG content, PCL-PEG-PCL triblock and PLA-PCL-PEG-PCL-PLA pentablock were synthesized, and then the block copolymer was chain-extended using hexamethylene diisocyanate (HDI) to synthesize polyurethane. The structure and polymer growth of the block copolymer were confirmed by 1H NMR, 13C NMR, and GPC. After urethane synthesis, chemical bonds and structures were analyzed through FTIR and XRD. The mechanical property tendency of the bio-elastomer according to the PEG composition and PLA addition was measured by UTM. In the biodegradability test, the weight loss, tensile strength change, and appearance change of the bio-elastomer over time were compared to confirm the difference in degradability according to the PEG content and PLA block addition. After checking the Tm of the bio-elastomer through DSC analysis, the filament was extruded, and finally, a desired patch shape was produced using a 3D-printer. The microstructure formation of bio-elastomer and pure PCL was confirmed under a microscope, and rheological properties was analyzed using a rheometer. The synthesized bio-elastomer is expected to be used for various uses in the medical field, as it is 3D-printable and has adjustable physical properties and biodegradability through structural control.