Photocurable Coatings to Improve the Mechanical Properties of 3D Printable Expanding Foams

Recent developments of highly expandable foaming pre-polymer
resins
for lithographic additive manufacturing have allowed for the creation
of structures larger than a printer’s build envelope. To fully
utilize the capabilities of this technology, the mechanical properties
of these foams must be improved. This manuscript presents one method
for strengthening these lightweight polymeric structures via aerosol
spray application of a high-strength, low-viscosity photocurable coating.
This method is free from the reliance on often complex, large, or
bulky on-site equipment ordinarily required by conventional high-strength
spray coating. The newly formulated photocurable resin can be applied
using an ordinary cordless paint sprayer and cured using sunlight
in less than a minute, enabling the rapid production of large, load-bearing
structures from a small volume of feedstock and low-cost portable
equipment. A comprehensive screening process for resin formulations,
detailed mechanical compression and tensile analysis of coated polymer
structures, and an applied technical demonstration of the technology
are described. The photocurable coating described herein greatly strengthens
porous polymeric structures using a method that can be easily implemented.