[Back]

P. Gauss, K. Seidler, H. Reghunathan, M. Kury, A. Svirkova, M. Marchetti-Deschmann, P. Dorfinger, T. Koch, J. Stampfl, N. Moszner, C. Gorsche, R. Liska:
"Tailored Photopolymer Networks Using Addition Fragmentation Chain Transfer";
Talk: XXII. Bratislava International Conference on Macromolecules, Bratislava; 09-06-2016 - 09-09-2016; in: "BIMac 2016 Programme Book and Book of Abstracts", (2016), ISBN: 978-80-89841-01-1; 12.

Addition fragmentation chain transfer (AFCT) reagents1,2 represent a powerful approach towards regulated photopolymer networks. Materials with enhanced properties (e.g. reduced shrinkage stress, improved toughness, higher conversion) are formed and help the development of photopolymerization in innovative applications such as biomedicine, microelectronics and 3D lithography. Bowman, et. al.3,4 have shown that allyl sulfides are potent AFCT reagents as additives to photopolymerizable formulations yielding materials with reduced shrinkage stress and improved mechanical properties.
Herein, we present the development of β-allyl sulfones5 and vinyl sulfonate esters6 as AFCT reagents regulating the photopolymerization of multifunctional (meth)acrylates. The radical curing mechanism is investigated starting from monofunctional resin systems using laser flash photolysis, NMR, GPC, photoreactor and MALDI-TOF experiments. Moreover, a coupled FTIR-photorheology set up is used to investigate the photocuring of multifunctional resins, thus proving the reduction of shrinkage stress and increased conversion. Final mechanical properties of the regulated networks show improved thermomechanical properties (DMTA), and high toughness (tensile test, Dynstat test). First 3D structures have been printed and a shape memory effect has been observed.

Photopolymers, Addition fragmentation chain transfer (AFCT)