3D Printing of Strong Lightweight Cellular Structures Using Polysaccharide-Based Composite Foams

Abstract

Polysaccharides are attractive sustainable resources for the fabrication of advanced materials, but the assembly of these building blocks into complex-shaped structures combining the high strength and low weight required in many applications remains challenging. We have investigated and optimized the rheological and mechanical properties of polysaccharide-based composite foams based on mixtures of methylcellulose (MC), cellulose nanofibrils (CNF), montmorillonite (MMT), and glyoxal and tannic acid. Such foams were found to be stabilized by the coadsorption of MC, CNF, and MMT at the air−water interface, while the complexation of the polysaccharides with tannic acid improved the foam stability. Tannic acid could also be used to tune and optimize the microstructure and the viscoelastic properties of the wet foam for direct ink writing of robust cellular architectures. Glyoxal had no noticeable effect on the properties of the wet foams but significantly enhanced the water resilience and stiffness of the lightweight material obtained after drying at ambient pressure and elevated temperatures with minimum shrinkage. The foams possessed a high porosity and displayed a specific Young's modulus and yield strength that outperformed other biobased foams and commercially available expanded polystyrene. The strong and water-resilient 3D printed foams can be surface modified using, for example, aminosilanes, which opens up applications for air purification and thermal insulation.

Scalable method for bio-based solid foams that mimic wood

“…The elastic moduli can only be determined along the major axis and those are MPa and MPa for Ecopulp and reference. The values of Y and on hard direction are close in magnitude to previous polysaccharide based foam materials with similar densities 31 .…”

Creaming Layers of Nanocellulose Stabilized Water-Based Polystyrene: High-Solids Emulsions for 3D Printing

“…The challenge is to retain the shape of the printed objects, especially upon drying, since 3D printed objects with high water content severely shrink, deform and crack. Many routes have been used to circumvent this such as use of additives, cross-linking or curing, formation of foams, dissolving and regeneration as well as freeze drying (Rees et al, 2015;Voisin et al, 2018;Wang et al, 2018;Mohan et al, 2020;Jiang et al, 2021). Nanocellulosic materials, among other biobased materials, have also been used in 3D printable bionanocomposites, frequently as a component in polymer filaments.…”

Direct Cryo Writing of Aerogels via 3D Printing of Aligned Cellulose Nanocrystals Inspired by the Plant Cell Wall

“…The 3D printing of cellulose-based materials in the context of "hydrogel to aerogel" has emerged in the past few years, including in wound healing applications [14,15], scaffolds [16][17][18], lightweight foams [19], and aerogel substrates for supercapacitors [20]. Nanocellulose-containing hydrogels and aerogels, as well the different approaches used to prepare these materials and their applications, have been recently reviewed by De France et al [21].…”