Fabrication of Polylactide/Carbon nanopowder filament using melt extrusion and filament characterization for 3d printing
Abstract
Conclusion
Fused deposition modeling (FDM) technology uses thermoplastic filament for layer by layer fabrication of objects. To make functional objects with desired properties, composite filaments are required in the FDM. In this thesis, less expensive mesoporous Nano carbon (NC) and carbon nanotube (CNT) infused in Polylactide (PLA) thermoplastic filaments were fabricated to improve the electrical properties and maintain sufficient strength for 3D printing. Solution blending was used for nanocomposite fabrication and melt extrusion was employed to make cylindrical filaments. Mechanical and electrical properties of 1 to 20 wt% of NC and 1 to 3 wt% of CNT filaments were investigated and significant improvement of conductivity (3.76 S/m) and sufficient yield strength (35MPa) were obtained. Scanning electron microscopy (SEM) images exhibited uniform dispersion of nanoparticles in polymer matrix and differential scanning calorimetry (DSC) results showed no significant changes in the glass transition temperature (Tg) for all the compositions. Perspective uses of this filament are for fabrication of electrical wires in 3D printed robots, drones, prosthetics, orthotics and others.
A brief review of nanofiller materials in thermoplastics and other host materials was made in this thesis along with the unique characteristics obtained. Composite filaments consisting of nano additive, carbon nanopowder (NC) and carbon nanotube (CNT) in polylactide (PLA) matrix that ranges from 1% to 20%NC and 1 to 3%CNT were successfully fabricated using melt extrusion. The advantage of melt extrusion is that it can be used for long filament fabrication and mass manufacturing. Mechanical, electrical and thermomechanical properties of the composite filaments were determined and a conductivity of 3.76 ± 0.84 S/m and a mechanical strength of ~36 MPa at 20% loading of NC were obtained. The glass transition temperature was not affected significantly as the NC% is increased and the SEM images showed that relatively uniform dispersion of the NC in polymer matrix. This conductive filament can be a promising solution for 3D printing of wire lining in robots, orthotics, and prosthetics using commercial FDM printers. Further research should be done to print prototypes and determine the characteristics of the structures and the efficacy of the approach.
Thesis report