3D-printed and injection molded polymer matrix composites with 2D layered materials

Two-dimensional layered materials (2DLMs), MoS2 and WS2, and three-dimensional (3D) graphite were infused in thermoplastic polymer matrices comprised of acrylonitrile butadiene styrene (ABS) and polyethylene terephthalate glycol (PETG). Two processing approaches were examined for creating polymer tensile test specimens using the composites for mechanical testing, which included three-dimensional (3D) printing and injection molding. The ductility generally decreased with the addition of the fillers indicated by an increase in Young’s modulus and a corresponding decrease in yield stress and tensile stress for the 2DLM-polymer composites. The dynamic friction data of the composites were measured in an attempt to exploit the solid phase lubricating properties of graphite and the 2DLM fillers. Graphite proved to lower the dynamic friction in the cases of 3D printed PETG and injection molded ABS, while MoS2 and WS2 were found to reduce friction in 3D printed PETG and ABS. Finally, the thermal conductivities of these polymer matrix composites were measured and compared to the pure polymer matrices. The thermal conductivity increased in both ABS and PETG composites containing graphite, MoS2, and WS2, irrespective of their processing routes. The use of 2DLM-based polymer composites remains an area of interest for a wide range of applications in the future, such as wearable electronics and sensors with low-cost additive manufacturing approaches.