Frontal polymerization of composites
Markus Fitzka1*, Michael Scheerer2, Zoltán Simon2, Thomas Rohr3, Donato Girolamo3, Robert Liska1 and Patrick Knaack1
1 Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9, 1060 Vienna (Austria)
2 Aerospace & Advanced Composites GmbH, Viktor-Kaplan-Straße 2, 2700 Wiener Neustadt (Austria)
3 European Space Agency (ESA), 2201 AA Noordwijk, The Netherlands
Radical Induced Cationic Frontal Polymerization (RICFP) is a self-preserving polymerization technique applicable for different industrially relevant resins like epoxides, oxetanes or vinyl ethers. After an initial and locally limited stimulus (heat or light), an exothermic polymerization is initiated via acidic species. The generated polymerization heat cleaves a thermal initiator into radicals which generate, via a redox reaction with a photo acid generator (e.g. iodonium and sulphonium salts) again the initiating acid. This cycle leads to a curing “wave” wandering throughout the whole resin. As only this first energy input is needed, this makes it a faster and more energy-efficient curing method than the state-of-the-art methods for curing such resins, which often include long curing cycles using autoclaves.
This principle is applied to particle and fiber filled composite1 as well as prepregs2 and filament winding applications.
References
1. Tran, A. D.; Koch, T.; Knaack, P.; Liska, R., Radical induced cationic frontal polymerization for preparation of epoxy composites. Composites, Part A 2020, 132, 105855.
2. Tran, A. D.; Koch, T.; Liska, R.; Knaack, P., Radical-induced cationic frontal polymerisation for prepreg technology. Monatshefte für Chemie - Chemical Monthly 2021, 152 (1), 151-165.