Vat photopolymerization using catalytic chain transfer polymerization (CCTP) derived reactive oligomers to influence mechanical properties†

ω-Vinyl terminated reactive oligomers of 2-ethylhexyl methacrylate and poly(ethylene glycol)methacrylate (PEGMA) were synthesized via catalytic chain transfer polymerization (CCTP) and subsequent addition–fragmentation chain transfer (AFCT) polymerization. The reactive oligomers were then incorporated into 3D-printing resins composed of isobornyl acrylate and poly(ethylene glycol)diacrylate (PEGDA). The formulations were used in digital light processing (DLP) 3D printing, and the mechanical properties of the printed parts evaluated. The effects of concentration, molecular weight and chemistry of the reactive oligomers additives were investigated. It was found that EHMA based reactive oligomers acted as plasticizers resulting in the weakening of the printed objects, whereas PEGMA based reactive oligomers transformed the objects from stiff and brittle to ductile elastomer-like materials.