The overarching goal of this project was to create innovative 3D printing materials for a conventional 3D printer. The presentation will be focused on the experimental procedure and results of conductive polylactic acid material. Conductive filaments allow us to 3D print color-changing and electrically conductive components using almost any commercially available desktop 3D printer. The electrically conductive filament was made with carbon black and clear polylactic acid (PLA) pellets.
Literature research was done to prepare necessary materials for experiments and design methods for synthesis. Experiments were carried out later to synthesize conductive PLA filament.
Two experimental methods were carried out to produce electrically conductive filaments. The first method was to heat up PLA until the pellets became fluid-like. Then varying weight percent of carbon black was added to the matrix and then stirred until the two substances were uniformly mixed. The second synthesis method involved a plasticizer, dichloromethane, to promote mixing of PLA and carbon black. The plasticizer’s purpose is to break the bond between the matrix and the filler, and triggers the formation of the composite. The sample was stirred for an hour then set on a watch glass for an additional hour to allow dichloromethane to evaporate. The sample was then placed in a water bath for one minute in order to separate the mixed filament from the watch glass.
The resistivity of each sample was measured with a multi-meter. For the first method, no resistivity reading was measured with 1wt% and 2wt% of carbon black. Resistivity varies depending on the distance between two electrical probes and their relative locations on the sample surface. The samples from both methods were observed using the scanning electron microscope. The images provided interesting surface features of the conductive composite.