[Zurück]

Y. Mete, A.D. Tran, N. Klikovits, D. Bomze, P. Knaack, R. Liska:
"Cationic Photopolymerization - Innovative Photoinitiators and their application for Bio-based Monomers and Frontal Polymerization";
Vortrag: European Polymer Congress 2019 (EPF 2019), Crete, Greece; 09.06.2019 - 14.06.2019; in: "European Polymer Congress 2019 (EPF 2019)", (2019), S. 114.

Until now, the field of applied photopolymerization has been mainly focused on radical polymerization. However, the introduction of iodonium salts as photoinitiators shifted the attention more towards cationic polymerization and its possible applications. We hereby present an aluminum-based Photo-Acid-Generator (PAG), which makes it possible to polymerize epoxy resins and various other monomers bubble-free and highly efficient (Figure 1). [1] At the same time the reactive formulations exhibit a long pot life and allow a one-pot-storage of the PAG and monomers.

Fig. 1: Aluminum-based Photo-Acid-Generator and the charge distribution of the anion

Beside traditionally used monomers for cationic polymerization, nature-inspired and other monomers, which provide possibly alternatives to established epoxy and bisphenol-A resins, are presented.
A very promising application of cationic photopolymerization is the radical induced cationic frontal polymerization (RICFP). This technique triggers a self-sustaining reaction front by using the initial photoinduced polymerization heat to decompose a thermal initiator, which again leads to further release of acid by the PAG (Figure 2). [2][3]
In our latest investigations, we did not only show that this enables bulk curing of resins and composites almost without any spatial restrictions, but that it can also be performed in an aqueous medium. This again gives impressive new opportunities for the application of RICFP, such as pipe or bridge reparations underwater.

applied photopolymerization, radical polymerization, iodonium salts as photoinitiators, cationic polymerization, aluminum-based Photo-Acid-Generator, polymerize epoxy resins, radical induced cationic frontal polymerization