Cellular, Mineralized, and Programmable Cellulose Composites Fabricated by 3D Printing of Aqueous Pastes Derived from Paper Wastes and Microfibrillated Cellulose

Abstract

to as additive manufacturing (AM) and 3D printing, has emerged as highly versatile digitalized processing technology in which digitally sliced computer-designed objects are directly translated into the layer-bylayer assembly of objects in the absence of molds. [5] During the pioneering days 3D printing technologies like stereolithography have served the specialized needs of niche markets like rapid prototyping. [6,7] However, at the beginning of the 21st century, the scope of additive manufacturing is broadening with respect to both the commercially available 3D printing technologies and their applications. Nowadays, apart from vat photopolymerization, AM includes powder bed fusion, binder jetting, sheet lamination, and extrusionbased 3D printing, which is highly robust and enables processing of an extraordinarily wide spectrum of organic and inorganic materials. [5] Extrusion-based AM can be divided into two different categories: fused filament fabrication (FFF), also named fused deposition modeling (FDM), and 3D dispensing. In the FFF process, pioneered in 1989, filaments of thermoplastics are fed into a heated nozzle in which the polymer melts, is extruded and 3D deposited on a built plate where it solidifies by means of glass transition or crystallization, respectively, after cooling. [8] In contrast, extrusion-based AM by 3D dispensing resembles hotmelt dispensing and had been established in 2000 for 3D printing of synthetic and natural polymers including 3D printing of melts, pastes, solutions, and dispersions. [9] In this 3D dispensing process, thermoplastics, thermosets, elastomer prepolymers, as well as synthetic and biopolymers, metal and ceramic pastes, cement, polymer solutions, and polymer dispersions are 3D printed by pneumatic 3D dispensing without using valves. Going well beyond the physical solidification typical for FFF of thermoplastics also chemical solidification by means of ionomer formation, crosslinking, and other chemical reactions including enzyme catalysis are feasible. Moreover, no temporary support structures are required in the so called zero-gravity 3D dispensing in which 3D printing takes place in a liquid media by carefully matching the density of the 3D printed material and the liquid printing medium. [5] Particularly in view of applications in regenerative medicine, the 3D dispensing process is highly attractive and has emerged as the technological base of Combining recycling of paper wastes (WPs) with extrusion-based additive manufacturing represents a sustainable route to cellular cellulose composites tailored for lightweight construction. Particularly, shear mixing of shredded WPs with an aqueous solution of a polymer binder like polyvinyl alcohol (PVA) yields aqueous pastes suitable for 3D printing. As a shear thinning additive, both WP and microfibrillated cellulose account for enhanced shear thinning and dimensional stability. Opposite to the formation of dense WP/ PVA composites by melt extrusion, 3D printing of aqueous pastes produces cellular cellulose/PVA composites ex...

3D printed cellulose based product applications

“…4.6.2 Recycled paper. StolzRolf and Mu ¨lhaupt 131 combined paper waste recycling with the addition of additives. The chopped waste recycling was mixed with polyvinyl alcohol as a polymer binder to produce a 3D printing paste.…”

Extending Cellulose-Based Polymers Application in Additive Manufacturing Technology: A Review of Recent Approaches

“…Other than water stimulus, cellulose, and PVA composite cross-linked with glyoxal were 3D printed and it was found that the printed structure had shape-memory properties responsive to heat and moisture [ 173 ]. The T g of the composite was 70 °C and its state could be changed by heating above the temperature.…”

Biocompatible Catechol‐Functionalized Cellulose‐Based Adhesives with Strong Water Resistance

“…[42][43][44][45][46][47][48][49][50] The hydroxyl groups on anhydroglucose units make cellulose suitable for a variety of physical or chemical modifications. [51][52][53][54][55][56][57][58][59][60] Especially, graft polymerization of various monomers on the cellulose backbone by atom transfer radical polymerization (ATRP) in a living/controllable way is expected to produce functional materials, which could combine the advantage of synthetic polymer and natural polymer properties. [54,[61][62][63] Therefore, it is meaningful to graft catechol-bearing monomers onto cellulose to make biocompatible adhesives with strong mechanical strength and water resistance through ATRP.…”