Electrospun nanofibres as a tool for controlling the gas bubble size distribution in fibre/thermoset-matrix composites

The influence of electrospun nanofibres made from polyamide 6 (PA6) on the gas bubble size distribution by volume in fibre/thermoset-matrix systems cured without a vacuum was comprehensively studied via various methods. An analysis of the microstructural, thermal and dielectric properties proved that the unique structure of PA6 electrospun nanofibres can withstand the curing conditions required for fibre/thermoset-matrix systems and that the overall dielectric behaviour of manufactured composites is not negatively influenced by the addition of nanofibres. Visual and numerical analyses of the tomograms obtained via X-ray computed microtomography (micro-CT) suggested that a nanofibrous structure can act as a solid grid limiting the growth of large gas bubbles or their random agglomeration during curing. The initial observations were independently supported by partial discharge analysis (PDA), which confirmed that the addition of nanofibrous layers leads to the presence of bubbles with generally smaller dimensions and that the nanofibrous layers significantly suppress the partial discharge (PD) activity inside a composite structure.