Three-Dimensional Printed Lightweight Composite Foams

Abstract

The goal of this paper is to enable three-dimensional (3D) printed lightweight composite foams by blending hollow glass microballoons (GMBs) with high density polyethylene (HDPE). To that end, lightweight feedstock for printing syntactic foam composites is developed. The blend for this is prepared by varying the GMB content (20, 40, and 60 volume %) in HDPE for filament extrusion, which is subsequently used for 3D printing. The rheological properties and the melt flow index (MFI) of blends are investigated for identifying suitable printing parameters. It is observed that the storage and loss modulus, as well as complex viscosity, increase with increasing GMB content, whereas MFI decreases. Further, the coefficient of thermal expansion of HDPE and foam filaments decreases with increasing GMB content, thereby lowering the thermal stresses in prints, which promotes the reduction in warpage. The mechanical properties of filaments are determined by subjecting them to tensile tests, whereas 3D printed samples are tested under tensile and flexure tests. The tensile modulus of the filament increases with increasing GMB content (8–47%) as compared to HDPE and exhibit comparable filament strength. 3D printed foams show a higher specific tensile and flexural modulus as compared to neat HDPE, making them suitable candidate materials for weight-sensitive applications. HDPE having 60% by volume GMB exhibited the highest modulus and is 48.02% higher than the printed HDPE. Finally, the property map reveals a higher modulus and comparable strength against injection- and compression-molded foams. Printed foam registered 1.8 times higher modulus than the molded samples. Hence, 3D printed foams have the potential for replacing components processed through conventional manufacturing processes that have limitations on geometrically complex designs, lead time, and associated costs.

Porous PLAs with Controllable Density by FDM 3D Printing and Chemical Foaming Agent

“…It is also seen that the tensile stiffness and strength of the 3D-printed PLA foams in this research have an increasing trend with increases in density. A similar stiffness–density variation trend was reported for tensile strength in References [ 13 , 14 ], while a decreasing trend was observed for stiffness in those references.…”

“…One category of porous polymeric structures is syntactic foams, which use hollow spheres in their matrix. Syntactic foams have been in use since the 1950s, and have thus been the focus of extensive research [ 12 , 13 , 14 , 15 ].…”

Additively manufactured foamed polylactic acid for lightweight structures

“…Customised characteristics can be achieved for many applications by varying the volume percentage of these hollow fillers in the matrix (Gupta and Ricci, 2006). H S et al (2020) produced lightweight syntactic foam composites by mixing various content of micro glass balloons (GMBs) with high-density polyethylene (HDPE) using the MEX process and studied their rheological and mechanical properties. The results showed that the foam specimens produced have higher specific tensile and flexure modulus in comparison to pure HDPE.…”

Digitally Tuned Multidirectional All-Polyethylene Composites via Controlled 1D Nanostructure Formation during Extrusion-Based 3D Printing

“…Spherical fillers and inorganic or organic fibers, as well as the addition of amorphous PP, have shown positive effects with respect to the warpage of PP and PP copolymers. − In contrast to PP or random PP copolymers, much less is known regarding the extrusion-based additive manufacturing of PE. Chinga-Carrasco et al reported on the fabrication and 3D printing of HDPE biocomposites reinforced with compatibilized thermo-mechanical pulp (TMP) fibers. , Various studies have also shown the usability of recycled HDPE from postconsumer waste, which once again underlines the outstanding position of polyethylene in terms of sustainability. − The authors often point out that the printing of pure HDPE is associated with poor adhesion and unacceptable warpage . In a recent advance, our group has shown that these problems associated with FFF of HDPE can be solved by selecting a suitable printing build plate and by optimizing the printing parameters to fabricate parts that exhibit mechanical properties similar to those obtained by conventional injection molding .…”

“…38−41 The authors often point out that the printing of pure HDPE is associated with poor adhesion and unacceptable warpage. 42 In a recent advance, our group has shown that these problems associated with FFF of HDPE can be solved by selecting a suitable printing build plate and by optimizing the printing parameters to fabricate parts that exhibit mechanical properties similar to those obtained by conventional injection molding. 43 Moreover, several groups have employed UHMWPE as an additive for the 3D printing of PP and ABS/poly(styrene-block-ethene-co-butene-block-styrene) (SEBS).…”