26 - 3D printing of fly ash-based syntactic foams

Abstract

In addition to the ease of fabrication using a wide range of forming processes, thermoplastic polymers are recyclable, which is a strong driving force behind their industrial applications. This chapter deals with manufacturing thermoplastic matrix lightweight composites called syntactic foams (SFs) using in the fused filament fabrication 3D printing process. High-density polyethylene (HDPE) is used as the matrix material and fly ash cenospheres are used as the filler. The development of SFs with cenospheres serves a dual purpose of beneficial utilization of industrial waste fly ash and a reduction in the component cost. Hollow fly ash cenospheres are mixed with HDPE to form a cenosphere/HDPE blend, which is extruded in the form of filaments for commercial 3D printers. Single-screw extruder parameters are optimized to develop eco-friendly SF filaments with minimum cenosphere fracture and homogeneous mixing of constituents. Fly ash-based SFs are successfully 3D printed for mechanical characterization and their properties are observed to be comparable to injection molded specimens of the same compositions. 3D printing of industrial components is successfully demonstrated with potential weight saving capabilities of 8% in addition to reduced polymer consumption to the tune of 4.64 million tons globally per year.