1 Accepted for publication in Polymer Composites Published in April, 2016 DOI: 10.1002/pc.23314 Toughened carbon fibre fabric-reinforced pCBT composites Tobias Abt 1 , J. Karger-Kocsis 2 and Miguel Sánchez-Soto 1* 1 Department of Materials Science. Centre Catalá del Plàstic. Universitat Politècnica de Catalunya. C/Colom 114, 08222 Terrassa, Spain. 2 MTA–BME Research Group for Composite Science and Technology, Muegyetem rkp. 3., H-1111 Budapest, Hungary. Abstract: Toughened carbon fibre reinforced pCBT composites were obtained by chemical modification of CBT with small amounts of epoxy resin and isocyanates as chain extenders. Homogeneous CBT/epoxy and CBT/isocyanate blends were prepared by melt blending the components in a lab-scale batch mixer at low temperatures and high shear rate. Melt blending was stopped before the ring-opening polymerization of CBT could start. The modified CBT was the starting material for carbon fibre fabric-reinforced pCBT composites (fibre content at about 70 vol.%) which were prepared by ring- opening polymerization during compression moulding using a simple powder prepreg method. Interlaminar shear strength, flexural strength and failure strain of the chemically modified composites increased up to 60% with respect to unmodified pCBT composites. Nevertheless, the flexural moduli slightly decreased due to the toughening effect of the chain extender on the pCBT matrix. Falling weight impact tests revealed that the energy absorption of the