Synthesis and characterization of polyurethane acrylate with bio-oil modification for photo-curing 3D printed flexible structures

The use of renewable resources for additive manufacturing has grown significantly as a means of advancing the ongoing shift to a green economy. This study uses bio-oil generated from the rapid pyrolysis of forest waste as a bio-based chemical to partially replace polyethylene glycol to synthesize a new type of bio-oil modified polyurethane acrylate, used in photo-curing 3D printing technology. The study explores the impact of the ratio of bio-oil to polyethylene glycol on the properties of polyurethane resin. As the amount of bio-oil added increases, the molecular weight of polyurethane acrylate decreases. Modified photosensitive resin showcases better suitability for photo-curing 3D printing, with lower viscosity and volume shrinkage, and its printed samples exhibit enhanced mechanical strength and improved thermal stability. In particular, when the bio-oil substitution rate is 20 wt%, the tensile strength of the 3D printed sample increases by 70 %, and the double bond conversion rate reaches 58.07 %. Meanwhile, the hollow and branching structures of 3D printing have the characteristics of high precision and flexibility. Introducing bio-oil into 3D printing technology not only expands the application fields of bio-oil but also provides new considerations for the transition of photosensitive resins from petroleum-based to renewable fields. [Display omitted] •The volume shrinkage rate of photosensitive resin greatly decreased with bio-oil modification.•The viscosity of photosensitive resin was significantly reduced by more than ten times after adding bio-oil.•The tensile strength of the mechanical specimen of 20BPUA resin was increased to 70 % higher than unmodified resin.•Bio-oil-modified polyurethane acrylate photosensitive resin can 3D print flexible structures and complex shapes.