Interlaminar fracture toughness of carbon fibre/RTM6-2 composites toughened with thermoplastic-coated fabric reinforcement

Abstract

Thermoplastic toughening of epoxy (RTM6-2)/ carbon fibre (CF) laminate composites without modification of the resin is reported, in which a CF fabric coated with 20 weight % of a poly (aryl ether ketone) (PAEK) was used to toughen composites. Dissolution of the PAEK during resin infusion, with subsequent reaction-induced phase separation and phase inversion during curing, formed PAEK-rich continuous layers with dispersed RTM6-rich particles within the interlaminar regions. These layers provided significant toughening during interlaminar fracture testing, in which the Mode I and Mode II fracture energies for the toughened system increased from 216±7.2 to 751±105 and 857±99 Jm-2 to 3316±372 Jm-2 , respectively. Thus, coating of the CF fabric with PAEK avoided the significant increases in viscosity observed with resin systems containing dissolved thermoplastics; whilst generating multiphase toughening layers at the CF fabric-matrix interfaces which provide efficient interlaminar toughening.

Bisphenol-A benzoxazine and cycloaliphatic epoxy copolymer for composite processing by resin infusion

“…In composite fabrication processes like vacuum resin infusion, a low viscosity resin at infusion temperature is required for the air removal, complete fiber wet-out, and impregnation, typically lower than 1000 mPa.s (cP) 11 and preferably 100 cP. 12 The high melt viscosity of BZ ( > 1250 cP) at common processing temperatures like 80℃–110℃, however, limits its applications in industrial manufacturing setups. 13 In addition to the explained process challenge, the glass-transition temperature of BZ (167℃) is smaller than that of the commonly used aerospace-grade infusion resin (RTM6, an epoxy system with the Tg of 212℃ 14 ), which limits its high-temperature application.…”

Multi-scale reinforcement of epoxy composites - Use of carbon fibre fabrics coated with an epoxy binder containing MWCNTs for improved interlaminar fracture resistance

“…Coating of the fabric surface has increased the rigidity of the CF tows, increasing their resistance to compression; which results in lower packing fractions of the tows [15] and can give higher levels of intra-tow voids in a composite laminate. However, the CF volume fractions of composites produced using coated fabrics can be increased by increasing the pressure and/or temperature applied during processing beyond that of the room temperature, vacuum-only pressure RI procedure used in this study; as reported from our Centre in [16] for CF fabrics coated with a thermoplastic toughener. Consequently a hybrid moulding technique, combining RI with hot-press moulding in a Dr Collin GmbH P300P/M press, was developed [16] to produce laminates with higher fibre volume fractions.…”

Polyetherketone powder/epoxy blends with low viscosity and high mechanical properties

“…It is generally accepted that diffusion of materials is significantly influenced by temperature. 33,34 For the undissolved blends, temperature is bound to affect the phase structure by adjusting the competition between the diffusion and separation of the PEK powder. Therefore, the phase structure of the undissolved 20 wt% PEK/DGEBA/M-DICY blends at different curing stages was investigated and compared with the dissolved ones.…”