Regenerated cellulose in additive manufacturing

Abstract

Environmental concerns within the 3D printing industry have attracted interest in finding biodegradable, eco-friendly material solutions. Cellulose is the most abundant natural polymer on the planet. Cellulosic pulp, derived from biomass, can be dissolved in eco-friendly solvents such as N-methyl morpholine N-oxide (NMMO) to produce Lyocell TM . Lyocell TM has had applications in the textile industry for the last decade. It has shown promise in producing highquality cellulosic fibers and the ability to be altered, tailored, and manufactured with ease. Despite this, additive manufacturing using cellulose is still an area of research with ample room to grow. In this work, we propose an in-depth study of using Lyocell TM to manufacture 3Dprinted parts using an affordable desktop 3D-printer modification. The 3D printing process of Lyocell TM is completely circular as the solvent can be recovered from 3D-printed parts, and the printed parts are biodegradable. The design of the developed 3D printing equipment, the rheological properties, and the 3D printing of the cellulose-NMMO solution are discussed in this work.

Structure Formation by 3D-Printing of Cellulose from Cellulose-NMMO-Water Solutions: Analysis of Extrusion, Regeneration, and Drying Stages

“…A detailed study on the capillary extrusion of cellulose-NMMO solutions was previously reported. 12 The shear viscosity, η, and first normal stress difference, N 1 , of 7.0% cellulose in the NMMO solution were measured as a function of shear rate, γȧ t different temperatures (Figure 1a). The sample showed a shear thinning behavior at all measured temperatures (80−130 °C) above the shear rate of 10 −1 s −1 .…”

“…Immediately after, the dope was removed from the vessel and stored in a lab refrigerator at 5 °C for further experiments. 12 All of the 3D printing experiments were carried out by using a dope from a single batch of preparation. Thus, the effects of possible variations in dissolving the cellulose further postextrusion were minimized.…”

“…These results are in line with our previous findings, where we hypothesize that remaining undissolved cellulose acts as small fiber reinforcements in a cellulose matrix. 12 Tensile properties of regenerated samples were also used to evaluate the interlayer fusion and bonding among stacked filaments. For this purpose, the effects of longitudinal (0°), transverse (90°), and bidirectional (0 and 90°) printing of 100 °C extruded and regenerated samples were investigated while testing in the longitudinal (0°) direction (Figure 6b,d).…”

“…However, drying a 3D object and controlling the shape integrity are more challenging than drying two-dimensional objects such as fibers and films while keeping them under tension. Following our first study on the viability of 3D-printing of regenerated cellulose, 12 this study is focused on the feasibility of obtaining dried 3D objects. We have focused on different stages, including the 3D-printing process.…”

Let’s Print an Ecology in 3D (and 4D)

“…Many other scientists and researchers, such as Hod Lipson, Neil Gershenfeld, Terry Wohlers, Elaine Cohen, and Jean-Claude André, have also made significant contributions, advancing various aspects of 3D printing through their work on specific mathematical modelling techniques. Some current applications involve characterizing the shear thinning behavior of inks by quantifying the degree of shear thinning and using mathematical models to predict the window of printer operating parameters within which Overall, each group of topics concerning 3D printing in an ecological context has the potential to contribute to a more sustainable manufacturing industry by reducing material and energy use and carbon emissions [6,[55][56][57]; conserving resources [7,58,59], repairing and upcycling [56,[60][61][62] and reducing waste generation [63][64][65][66]; facilitating the selection of eco-friendly materials [67][68][69][70][71]; and enabling decentralized and customized production processes [72][73][74], thus contributing to holistic assessments of environmental impacts. In the group of publications related to modelling, there is a significant emphasis on understanding printing conditions and the properties of various printed materials.…”