With the use of Addition Fragmentation Chain Transfer (AFCT) Reagents one is able to delay the gel point to higher conversions and therefore reduce the shrinkage process significantly. Furthermore the toughness of the material can be increased by a factor of up to ten due to the more homogeneous network architecture [1,2]. A new generation of vinylsulfones also allows polymerization even without delay [3-5]. Furthermore, ester activated vinyl ethers [6] and cyclopolymerizable AFCTs [7] have been developed.

[1] C. Gorsche, T. Koch, N. Moszner, R. Liska:
"Exploring the benefits of β-allyl sulfones for more homogeneous dimethacrylate photopolymer networks";
Polymer Chemistry, 6 (2015), S. 2038 - 2047.

[2] C. Gorsche, M. Griesser, G. Gescheidt, N. Moszner, R. Liska:
"β‑Allyl Sulfones as Addition−Fragmentation Chain Transfer Reagents: A Tool for Adjusting Thermal and Mechanical Properties of Dimethacrylate Networks";
Macromolecules, 47 (2014), 21; S. 7327 - 7336.

[3] C. Gorsche, K. Seidler, P. Knaack, P. Dorfinger, T. Koch, J. Stampfl, N. Moszner, R. Liska:
"Rapid formation of regulated methacrylate networks yielding tough materials for lithography-​based 3D printing";
Polymer Chemistry, 7 (2016), 11; S. 2009 - 2014.

[4] K. Seidler, M. Griesser, M. Kury, H. Reghunathan, P. Dorfinger, T. Koch, A. Svirkova, M. Marchetti-Deschmann, J. Stampfl, N. Moszner, C. Gorsche, R. Liska:
"Vinyl Sulfonate Esters: Efficient Chain Transfer Agents for the 3D Printing of Tough Photopolymers without Retardation";
Angewandte Chemie - International Edition, 57 (2018), 29; S. 9165 - 9169.

[5] C. Gorsche, K. Seidler, H. Reghunathan, M. Kury, T. Koch, N. Moszner, R. Liska:
"Difunctional vinyl sulfonate esters for the fabrication of tough methacrylate-​based photopolymer networks";
Polymer, 158 (2018), S. 149 - 157.

[6] G. Peer, A. Eibel, C. Gorsche, Y. Catel, G. Gescheidt, N. Moszner, R. Liska:
"Ester-Activated Vinyl Ethers as Chain Transfer Agents in Radical Photopolymerization of Methacrylates";
Macromolecules, 52 (2019), 7; S. 2691 - 2700.

[7] S. Schörpf, Y. Catel, N. Moszner, C. Gorsche, R. Liska:
"Enhanced reduction of polymerization-induced shrinkage stress via combination of radical ring opening and addition fragmentation chain transfer";
Polymer Chemistry, 10 (2019), S. 1357 - 1366.