Single fibre pull-out test for the material selection of a hybrid resin composite

Fibre-resin-interface is an important composite parameter for the mechanical properties of fibrereinforced plastics. An insufficient interface between fibres and resin leads to early debonding between both materials and therefore premature failure in the overall composite. Moreover, the interface characteristic is essentially driven by the fibre sizing. Here, several fibre sizings exist for carbon fibres, which are just suitable either for thermosets or for thermoplastics. It is becoming exciting, when a thermoset as well as a thermoplastic is implemented in one common composite and an additional carbon fibre woven fabric lays in between both resin system. Then, a trade-off regarding the carbon fibre including the fibre sizing need to be done to optimize the hybrid composite system. In an experimental testing study, the fibre-pull-out test was used to make a statement regarding the interface properties of different fibres and resin systems, especially thermoplastics like PEI, PVDF and PA6. Here, the testing devices, FIMABOND and FAVIMAT+, were used to realize the tests. To evaluate the ideal fibre embedding conditions, rheological tests were done with the thermoplastics. Furthermore, the tensile strength of the fibre material should be known, because it can influence the embedding depth. Some embedded fibres were scanned by an x-ray microscope to ensure the quality of the specimens and to optimize the embedding cycle. Here, design recommendations were given for the ideal fibre embedding with FIMABOND.