TITLE:
Characterization of Fiber Dust Resulting from Recycling of Carbon Fiber-Reinforced Thermoplastics (CFRP) and Their Cell Toxicity
AUTHORS:
Lisa Tölle, Christian Monsé, Nina Rosenkranz, Natalia Haibel, Dirk Walter, Jürgen Bünger, Matthias Hopp, Götz A. Westphal
KEYWORDS:
Carbon Fibers, Fiber Dust, Recycling, Toxicity
JOURNAL NAME:
Journal of Materials Science and Chemical Engineering,
Vol.10 No.7,
July
14,
2022
ABSTRACT: Carbon fiber-reinforced
thermoplastics (CFRP) have excellent specific strength and rigidity,
which has made them a popular material for lightweight construction. The
growing demand for fiber-reinforced plastics (FRP) leads to the problem of the
sustainable handling of FRP at the end of their life cycle. The aim of the
research project was to gain knowledge about the shredding of FRP concerning
the optimal machine and process design of the shredding process and the
possible formation of harmful, inhalable dust fractions and WHO fibers.
Toxicity should be investigated at the cellular level. The investigated
shredding parameters influence the amount and length of fiber dust produced,
both when shredding with a cutting mill and when shredding with a single-shaft
shredder. In all investigations, an increasing rotational speed leads to an increase
in the fiber dust mass or the fiber concentration. The proportion of short,
respirable fibers increases, but raising the speed does not lead to a further,
significant shortening of the fibers. A reduction in feedstock size leads to a
slightly reduced mass of fiber dust in the ground material. A reduction in the screen size also leads to an increase in fiber dust mass and concentration. There was no
recognizable cytotoxicity in the relevant concentration range up to 500 μg/cm2 and no significant induction of cell migration. This indicates minor flammable
effects of the dust formed after inhalation. The biological data indicate that
the WHO fibers produced by shredding are only
a minor health hazard. Formally, the detected carbon fiber (CF)
fragments meet the fiber definition of the legislator. However, carbon fibers
currently have no specific limit value.