# Sustainable Approaches for Carbon Powder-Filled ABS: A Comparative Study of Injection Moulding and Fused Filament Fabrication Technologies

## TL;DR

This study compares injection moulding and 3D printing for recycling ABS plastic with carbon powder, finding that both methods can produce strong materials suitable for reuse.

## Contribution

The study demonstrates the feasibility of recycling ABS+carbon powder composites using injection moulding and FFF, with improved mechanical properties after recycling.

## Key findings

- ABS+1.5 wt.% CP composites showed a 3% increase in tensile strength and 15% increase in elastic modulus after re-injection moulding.
- FFF reprocessing of ABS+1.5 wt.% CP resulted in 12% higher tensile strength and 27% higher elastic modulus compared to virgin ABS.
- Recycled ABS+CP composites maintain structural integrity and offer a granite-like appearance suitable for structural and decorative applications.

## Abstract

The recycling of polymer composites remains a significant challenge due to both technical and economic obstacles. This study investigates the recycling potential of acrylonitrile butadiene styrene (ABS) composites filled with carbon powder (CP), employing injection moulding and fused filament fabrication (FFF) technologies. Laboratory-based experiments were conducted using ABS reinforced with 0.5, 1.0, and 1.5 wt.% CP to explore the tensile properties of mechanically recycled ABS+CP composites. The results indicate that CP addition positively influences tensile behaviour and that the ABS+CP composite maintains both tensile strength and stiffness after repeated processing. A concentration of 1.5 wt.% CP proved to be the optimal filler amount. The results for re-injection-moulded ABS + 1.5 wt.% CP demonstrate enhancements in tensile strength of approximately 3% and elastic modulus of approximately 15%, relative to virgin ABS. Similarly, such specimens reprocessed via FFF showed an average increase of 12% in tensile strength and of 27% in elastic modulus relative to virgin ABS across all three printing orientations (X, Y, and Z). These findings suggest improved interfacial adhesion and filler dispersion upon recycling. The study confirms the practical feasibility of ABS composite recycling and highlights their potential for structural and decorative use due to their appealing granite-like appearance.