Latent CO 2 -Protected N-Heterocyclic Carbene-Based Single-Component System-Derived Epoxy/Glass Fiber Composites a Michael R. Buchmeiser,* Jochen A. Kammerer, Stefan Naumann, J€ org Unold, Ravand Ghomeshi, Sathis K. Selvarayan, Patrick Weichand, Rainer Gadow Epoxy-based fiber–matrix composites based on a single-component curing system with pot times >>two weeks are described. Bisphenol-A-diglycidyl ether and hexahydrophthalic anhydride were used as epoxy matrix precursors; 1,3-dicyclohexyl-3,4,5,6-tetrahydropyrimi- dinium carboxylate (6Cy-CO 2 ) was used as latent pre-catalyst. Glass fiber-reinforced epoxy resins were obtained both via thermal curing under air and under vacuum-assisted resin infusion conditions. The high quality of the resulting composites and the absence of any air inclusion were confirmed by DSC and x-ray tomography. Rheological and kinetic data revealed that the 6Cy-CO 2 -based systems allow for an advanced processing and outrival commercial amine-based hardeners in terms of speed of curing. 1. Introduction Fiber–matrix composites, whether based on carbon, aramide, or glass fibers, [1] play a predominant role in light-weight construction. [2] For high performance, a few prerequisites have to be fulfilled. [3] First, the fibers as such must possess the required mechanical strength. In that context, particularly tensile strength and Young’s modulus are of great importance. Second, the fibers must be transformed into wovens or non-wovens. Particularly wovens can be tailored to meet the demands in terms of external load transmission to the composite. Third, the polymeric matrix needs to display tailored properties that fit the corresponding application. Fourth, the matrix must strongly bind to the fibers to ensure perfect load trans- mission of the matrix onto the fibers. Besides these chemical and engineering requirements, there are some additional issues to be fulfilled. Thus, neither woven nor non-wovens can be filled, i.e., penetrated with thermo- plasts, even at high temperature. It is the high melt viscosity of thermoplasts that basically impedes any complete infusion. However, fibrous matrices can be infused with low viscosity solutions or melts of monomers. Prior to infusion, these are mixed with the catalyst. Nonetheless, in order to reduce costs and to meet the expectations in terms of length of cycle, single-component systems are desperately M. R. Buchmeiser, J. A. Kammerer, S. Naumann Institute of Polymer Chemistry, University of Stuttgart, 70569 Stuttgart, Germany E-mail: michael.buchmeiser@ipoc.uni-stuttgart.de M. R. Buchmeiser, J. Unold Institute of Textile Chemistry and Chemical Fibers, K€ orschtalstr. 26, D-73770 Denkendorf, Germany R. Ghomeshi, S. K. Selvarayan Institute of Textile Technology and Process Engineering, K€ orschtalstr. 26, D-73770 Denkendorf, Germany P. Weichand, R. Gadow Institute for Manufacturing Technologies of Ceramic Components and Composites, University of Stuttgart, 70569, Stuttgart, Germany a Supporting Information is available from the Wiley Online Library or from the author. Full Paper ß 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim DOI: 10.1002/mame.201500090 937 Macromol. Mater. Eng. 2015, 9, 937–943 wileyonlinelibrary.com