Process technology for the autoclave consolidation of fibre composites with a high-temperature thermoplastic matrix material has been developed and investigated. Five different types of carbon fibre/PEEK (PolyEtherEtherKetone) have been examined: APC-2 solid prepreg (pre-impregnated) tape from ICI; Quadrax 5 Harness Satin prepreg fabric from Quadrax; and unidirectional, 8 Harness Satin and 5 Harness Satin postpreg (post impregnated) fabrics of Filmix(TM) (a drapeable yarn spun from a blend of carbon and PEEK fibres) from Heltra Inc. The influence of autoclave pressure, pressure cycle and additional matrix material in the form of PEEK films on laminate quality and properties are reported. The laminates are characterised by microscopy, fibre content, porosity, inter-laminar shear strength (ILSS), bending strength and bending modulus. High-duality laminates with less than 1% porosity can be fabricated from APC-2 unidirectional tapes at a pressure of 0.3 MPa, whereas a woven fabric of Filmix(TM) requires a pressure 2.0 MPa in order to produce laminates which also have less than 1% porosity. By adding a small amount of extra matrix material in the form of PEEK films to the Filmix(TM) material, an autoclave pressure of only 0.7 MPa can produce laminates with a porosity of less than 1%. The ILSS is relative high (100-120 MPa) for all the laminates. It was expected that in general, a higher ILSS of the Filmix(TM) laminates would be found, since the nature of the yarn construction creates some fibre bridging between the different plies in the laminate, but the ILSS of the UD-laminates is 20% higher for the APC-2 laminates. This is caused by a very homogeneous fibre distribution with no matrix-rich areas in the APC-2 laminates, whereas thin matrix rich layers are observed by microscopy in the UD-Filmix(TM) laminates. (C) 1998 Elsevier Science S.A. All rights reserved.
