posted on 2024-02-26, 05:43authored byLaura Ballester-Bayarri, Alodi Pascal, Jon Ayestaran, Alba Gonzalez, Nicholas Ballard, Robert Aguirresarobe
Covalent adaptable
networks (CANs) have the potential
to combine
the excellent mechanical properties of traditional thermoset materials
with the reprocessability of traditional thermoplastics. However,
the processing of CANs using common techniques for thermoplastics
has proven challenging. In this work, the 3D printing of reprocessable
CANs with controlled shape is reported using vat photopolymerization
(VP). Using a vinylogous urethane-containing methacrylic cross-linker,
a series of resins containing nonreactive and reactive diluents are
described. The resin viscosity can be easily tuned by the relative
amount of diluent to functional cross-linker such that the viscosity
of commercial resins can be easily achieved. By studying the curing
kinetics using Jacob’s equation, optimal printing conditions
are found that allow for high-resolution printing with limited shrinkage.
In addition, due to the presence of dynamic bonds in the final material,
it is shown that the final printed piece can be reprocessed at high
temperatures and can even be recycled into a second-generation resin
that can be reprinted.