A holistic approach to use multi-scale fractions of dry carbon fibre production waste in filled bulk moulding compounds (BMC)

The increasing demand for composites leads to a growing amount of end-of-life material and production waste. The latter consists of a large fraction of unimpregnated fibre waste which is not sufficiently reprocessed using conventional textile processing procedures as they are either too expensive or their mechanical performance is too low. Using pieces of dry non-crimp fabrics (patches) in a Bulk Moulding Compound process (BMC) displays a straightforward approach of fabric recycling. Adding fillers to the mixture not only offers the opportunity to modify mechanical and electrical properties as well as the costs but also a chance for a more holistic approach of dry fibre recycling, when conventional fillers like chalk are replaced by ground recycled carbon fibres. In this way, all kind of dry fibre wastes can be reused in one process: Larger offcuts are chopped to smaller rectangular patches whereas waste fractions of small offcuts are processed to carbon fibre powder as filler and processed together with resin to produce BMC materials. Mechanical investigations reveal that the presented approach shows higher specific properties than the conventional filler without compromising the process and material quality.