Interface stress transfer in an extruded ABS-rGO composite filament

Abstract

Thermoplastic composite materials are typically used as feedstock filaments in material extrusion-based 3D printing. Understanding the mechanism of stress transfer at the filler/matrix interface in a composite filament helps in improving its properties. In this work, ABS/reduced graphene oxide (rGO) composite has been prepared by the solution mixing method, and 3D printable filaments are made by single screw extrusion. At filler loading of 0.2 wt. %, tensile strength of the composite filament is increased by ~40 % compared to the neat ABS filament. To understand the mechanism of stress transfer , a multi-scale mathematical model is presented. At the microscale, interface stress transfer is studied by using two-dimensional finite element (FE) analysis. The filler dimensions required for FE analysis are estimated using XRD and Raman analysis of rGO. In the present case, the filament making process yields filler dimensions comparable to the critical length, hence providing better stress transfer. The macroscopic strength of nanocomposite is estimated by using rule of mixtures. The better interface stress transfer and extrusion-induced filler orientation increases the filament strength. T.