Thermal conductive composites for FDM 3D printing: A review, opportunities and obstacles, future directions

This review documents the current possibilities for producing a thermally conductive polymer or composite material designated for 3D printing, which could be used for the construction of items with high thermal con-ductivity. There is a wide range of 3D printing techniques that use a number of different principles. These include FDM (Fused Deposition Modeling) or FFF (Fused Filament Fabrication), SLA (Stereolitography), DLP (Digital Light Processing), and SLS (Selective Laser Sintering), to name a few. This review is focused on the use of 3D printing techniques for application in FDM printing since it is the most common technique. In recent years, this technology has become one of the most widely used methods for cheap and rapid prototyping, but also for the manufacture of end parts at lower costs. However, filaments made from various polymers such as PLA (Polylactic Acid), ABS (Acrylonitrile Butadiene Styrene), ASA (Acrylonitrile Styrene Acrylate), PC (Polycarbonate), PPS (Polyphenylene Sulfide), PEEK (Polyether Ether Ketone), and others are generally very good thermal insulators and do not conduct heat. There are many applications where some advanced properties such as thermal con-ductivity should be beneficial. These types of materials have potential to be used in various heat-intensive ap-plications, such as a material for heat sinks, heat exchangers, or mold tooling, (generally wherever heat exchange between systems is required), with the advantage of lower weight and simpler processing compared to, for example, metal equivalents. There are several ways to improving thermal conductivity of plastic parts. This paper will discuss crystallinity and modification of molecular orientations, the possibility of incorporating thermally conductive fillers into a thermoplastic matrix by random distribution and the formation of a segregated structure, as well as imitation of the segregated structure by coextrusion. The influence of individual modifications of the polymer on its mechanical properties will also be considered.