Fused Deposition of PLA Matrix Composite for 4D Applications

Abstract

In the past two decades, fused deposition modeling (FDM) has been explored widely as one of the low-cost additive manufacturing (AM) techniques for a different range of thermoplastics and thermoplastic composites. In the current scenario, various industries (such as medicine, construction, mechanical, electrical, etc.) are using FDM for printing critically designed products. Various range of polymeric materials such as polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), polyamide (PA6), polyvinyl chloride is available for FDM applications. PLA is one of the widely used materials for FDM applications. Especially bio compatibility issues have been explored widely by various research groups. But little has been reported on the in-house feedstock filament development and printing capability for multi-material (product comprising of different composite materials at each successive layer of 3D printed design) and hybrid composites (all reinforcements in a single composite). In this work, PLA was reinforced with PVC, wood powder, and magnetite powder (Fe3O4) for preparing multi/hybrid composites to support 4D applications. The reinforcement of PVC in PLA has been chosen to make the PLA material flexible and use the waste PVC in the PLA matrix. The wood powder has been reinforced in the PLA matrix to reduce the thermal conductivity to control the heat flow from the material matrix. Fe3O4 powder has been used to provide the 4D capability to the newly designed composite matrix to acquire the property of self-assembly when triggered with the external magnetic field (as stimulus). Two different types of prototypes (a) hybrid blend (PLA/PVC/wood powder/Fe3O4 powder in single composite) and (b) multi-material with four different feedstock filaments ((a) PLA, (b) PLA/PVC, (c) PLA/wood powder and (d) PLA/Fe3O4 powder) have been used in a single prototype. To explore the properties of two different types of prototypes, the selected material matrix has been initially prepared as feedstock filament using twin-screw extrusion (TSE) followed by 3D printing on an FDM setup. At each step of processing, Taguchi orthogonal array (OA) approach has been used to prepare the components so that optimization of processing conditions may be achieved for maximizing the results. After developing functional prototypes of different combinations, properties such as mechanical, morphological, rheological, thermal and magnetic, were tested. Finally, the prepared composites were tested for addressing the recycling issues.