MEASUREMENT OF INTERFACIAL SHEAR-STRENGTH OF CARBON FIBRE EPOXY COMPOSITES USING A SINGLE-FIBER PULL-OUT TEST/

Single fiber pull-out tests were conducted for G34-700/Araldite-F, T70 0S/Araldite-F and T800H/Araldite-F model composites using an improved experimental set-up to evaluate the interfacial shear strength (IFSS). The modified method made it possible to reduce the formation of resin meniscus and to accurately define the embedded fibre length, and it a lso provided a practical approach to conveniently estimate the IFSS fo r comparison of the fibre-matrix adhesion between different composite systems or different fibre surface conditions. A strong interfacial ad hesion and unstable debonding process without detectable friction stag es were found for all types of model composites with fibres being chem ically treated/sized or sizing being removed. The electrochemical oxid ation treatment and sizing on the carbon fibres noticeably increase th e IFSS of the composites.