Effect of Photo-Polymerization and Phase Separation Kinetics on the Structure-Property Relationship of 3D Printing Resins Using PPG

The physical properties of 3D printed porous materials can be tailored via photo-polymerization-induced phase separation. The competition between photo-polymerization kinetics and phase separation can be studied through use of a multiscale method to show the extent of phase separation and its overall effect on the material once 3D printed. A main characterization method of phase separation is a UV transmittance experiment performed using a custom-built light transmission apparatus. Additional characterizations have been performed to get information on the photo-polymerization kinetics and morphology of the polymer films such as real time-fourier transform infrared spectroscopy, polarized optical microscopy, and scanning electron microscopy. Compression testing and tensile testing have been used to characterize the mechanical properties of the molded material. Polypropylene glycol (PPG) is used as a polymer additive. PPG-containing resins show a drastic increase in turbidity upon photo-polymerization. By altering the composition and molecular weight of PPG additive used, the extent of phase separation and therefore the mechanical properties of the material can be tuned.