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S. Ligon, M. Schwentenwein, C. Gorsche, J. Stampfl, R. Liska:
"Toughening of photo-curable polymer networks: a review";
Polymer Chemistry, 7 (2016), 257 - 286.

Photo-curable resins based on multifunctional acrylate monomers are commonly applied as thin films (e.g. protective coatings, printing inks, etc.) and in recent years are also used for the fabrication of bulk objects such as dental fillings or 3D-printed parts. While rapid curing and good spatial resolution are advantages, brittleness and low impact resistance due to inhomogeneous polymer architecture and high degrees of crosslinking are serious drawbacks. By comparison, epoxy thermoset resins suffered many years ago from similar problems, but since then are found in ever demanding applications thanks to a variety of approaches to increase polymer toughness. Based on these successes, researchers have tried to translate strategies for toughening epoxy resins to photopolymer networks.
Therefore, this review surveys relevant scientific papers and patents on developing crosslinked epoxy-based polymers and also photo-curable polymers based on multifunctional acrylates with improved toughness. Strategies developed to reduce brittleness include working with monomers, which intrinsically contribute to tougher polymers, particulate additives, and alternate forms of polymerization and polymer architecture (e.g., dual-cure networks, interpenetrating networks, thiol-ene chemistry). All of these strategies have advantages and yet application specific rigours must also be considered before and during formulation development.

http://dx.doi.org/10.1039/c5py01631b

Project Head Jürgen Stampfl:
Neue Konzepte zur Zähigkeitssteigerung 3D-druckbarer Photopolymere