The mechanical properties of materials printed using fused filament fabrication (FFF) 3D printers typically
rely only on adhesion among melt processed thermoplastic polymer strands. This dramatically
limits the utility of FFF systems today for a host of manufacturing and consumer products and severely
limits the toughness in 3D printed shape memory polymers. To improve the interlayer adhesion in 3D
printed parts, we introduce crosslinks among the polymer chains by exposing 3D printed copolymer
blends to ionizing radiation to strengthen the parts and reduce anisotropy. A series polymers blended
with specific radiation sensitizers, such as trimethylolpropane triacrylate (TMPTA) and triallyisocyanurate
(TAIC), were prepared and irradiated by gamma rays. Differential scanning calorimetry
(DSC), tensile testing, dynamic mechanical analysis (DMA) and attenuated total reflectance Fourier
transform infrared spectroscopy (ATR-FTIR) were employed to characterize the thermomechanical
properties and the chemical structure of the various polymers. TAIC was shown to be a very effective
radiation sensitizer for 3D printed sensitized polylactic acid (PLA). The results further revealed that
crosslinks induced by radiation temperatures near Tg of shape memory systems have prominently
enhanced the thermomechanical properties of the 3D printed polymers, as well as the solvent resistance.
This enables us to deliver a new generation of inexpensive 3D printable, crosslinked parts with robust
thermomechanical properties