Macromolecular Engineering of Degradable Photocurable Resins*

Photocurable resins, typically consisting of a combination of multi-functional monomers and oligomers, a photoinitiator, and an optical absorber, are formulated for numerous applications in light-based 3D printing. By strategically incorporating novel, biocompatible, anhydride-based oligomers that are available solely through our innovative synthesis route, formulation development has provided expanded physical properties of 3D-printed materials that chemically degrade in the presence of water. Chemical degradation leads to controlled and predictable erosion of the crosslinked network from the surface inward on a time span of hours, days, or weeks. The physiochemical behavior of the polymer network in unique environments is heavily influenced by incorporation of different degrees of hydrophobicity into the matrix backbone. Practical material-oriented methods of altering the capability for anhydride-based materials to degrade in their solid state at controlled rates include changing the monomers that are used, changing the length of the monomer, changing functionalities that are associated with the ‘R’ group of the polymer (i.e., the internal structure of the monomer), and changing the formulation of the photocurable resin. Characterization techniques for measuring the erosion rate, mechanical integrity, water uptake, and swelling of the parts that are 3D printed upon exposure to water are explored. Future work includes the incorporation of functionalized particles and fillers for advanced applications that require controlled and predictable delivery.