Nanofibres in Composites (Sam Van der Heijden) (2013 - 2016)

Thermoset matrix fibre reinforced composites are widely used in industry, due to their light weight, high stiffness and strength. However, these composites still face a serious problem as the thermoset matrix is a brittle material. This can lead to failure of the composite due to relatively low out of plane impacts. It is also the main cause of delamination. Furthermore, it negatively affects the fatigue properties of the composite. Several solutions have been proposed to enhance the toughness of epoxy composites. Most of them make use of nano- or microsized filler particles, in general it is proven difficult to obtain a homogeneous dispersion of these particles. This leads to agglomerations which can induce stress concentrations and may even reduce the overall performance of the composite. Furthermore, there is a growing concern about health issues involved in the use of nanoparticles.

Thermoplastic nanofibres have the potential to provide a solution for these problems. Nanofibrous webs can be readily embedded in the resin; they have the large benefit of their inherent nanoscale distribution, which may improve the traditional limitations in (nano) particle dispersion. Owing to their macro-scale length, no health hazards are involved in the production and use of electrospun nanofibres. In addition, the non-woven structure of the nanofibres could initiate toughening by fibre bridging. Moreover, the use of polymers with the appropriate functional groups may further enhance this bridging effect. Recent literature indicates that nanofibres may contribute substantially to the ductility and fracture toughness of the composite. Notwithstanding some of the obvious benefits of nanofibres over nano- and thermoplastic particles, the research on nanocomposites with electrospun nanofibres has been very limited. Only a few papers have been published, in which the authors made use of very small-scale samples. Furthermore, a systematic study starting from the processing parameters of the electrospinning till the resulting mechanical properties of the nanocomposites has not yet been done. But both such a study and an upscaling of the production to medium-scale samples are prerequisite for future market applications. Therefore these are the main objectives of this project.

The “nanoscale” parameters such as nanofibre diameter, nanofibre web (thermo)mechanical properties and the effect of different functionalizations will be investigated. These nano-scale parameters will be linked to macro-scale (thermo)mechanical parameters which are highly relevant to industrial applications. Whereas the “nano-scale” parameters are highly relevant for a profound understanding of the impact of nanofibres on the (thermo)mechanical properties of composites.

Supported by: IWT
Duration: 01/2013 – 12/2016
Contact: ir. Sam van der Heijden - Prof. Dr. ir. Karen De Clerck