3D Printing of Green and Renewable Polymeric Materials: Toward Greener Additive Manufacturing

Abstract

There is an ever-growing push toward sustainability and green manufacturing in a wide array of industries, especially 3D printing, which is now recognized as a viable manufacturing method. The number of studies focusing on leveraging additive manufacturing of natural products continues to grow, with key areas of interest including exciting chemistries or modifications of natural products toward 3D printable materials, advancements in prototypes or products by changing feedstocks to green or bioderived alternatives, and the introduction of added functionalities or properties. This includes concepts such as processing natural or bioderived polymers into filament for extrusion-based 3D printing, the design of photopolymer resins and inks for vat photopolymerizations, jet printing, or direct ink writing processes, and the use of powders for selective laser sintering. The strategies employed to achieve materials suitable for 3D printing, the physical properties of the materials, and the resultant applications including strengths and limitations, will be explored in this review. Overall, the advancements in the field are leading to future opportunities in biomaterials and medical devices, electronics and batteries, and environmental remediation and water purification.

Enabling New Approaches: Recent Advances in Processing Aliphatic Polycarbonate‐Based Materials

“…As illustrated in Figure 14, a typical FDM printer melts a thermoplastic filament which rapidly cools and solidifies after extrusion, whereas DIW is most performed at room temperature. [110,[126][127][128] DIW feedstocks, also known as "inks," are yield-stress fluids typically composed of highly particle filled polymer solutions. These viscous, paste-like inks can be extruded through a syringe, layered to form 3D printed structures, and solidified during or after printing via solvent drying, ultraviolet curing, chemical curing, or heating/cooling the printed ink.…”

“…The selective laser sintering (SLS) technique uses a laser beam as the power and heat source to selectively fuse the particles of a polymer powder together layer by layer, while fresh powder is spread onto the previously bonded layer [109] . As illustrated in Figure 10A, the materials used in SLS are usually thermoplastic polymers in a granular form, which is attainable for linear aPCs with naturally low melting temperatures [110] . Figure 10Bi shows a lattice structure printed with SLS technique using a powder mixture of aPC and hydroxyapatite (HA) particles prepared by ball‐milling [108] .…”

Organocatalysis in ring opening copolymerization as a means of tailoring molecular weight dispersity and the subsequent impact on physical properties in 4D printable photopolymers

“…Additive manufacturing has become one of the most prominent new methods of producing unique or personalized prototypes and devices. [1][2][3][4] 3D printing technology, properly utilized, would provide avenues towards patient-specific implants in clinical settings. Achieving such a goal requires the parallel development of both the materials platform (the printable materials) as well as the processing methodologies.…”

4D Photopolymers Derived From Ring-Opening Copolymerization of Cyclic Anhydrides and Limonene Oxide

“…Recently, terpenes have been of interest as greener alternatives to commodity polymers. − Weems et al utilized terpenes as both monomeric and polymeric photopolymers, Merckle et al and the Reineke groups have shown modification of monomeric terpenoids toward photopolymer resins, and Constant and coauthors demonstrated the copolymerization of such materials for photopolymers. ,,,, In these instances, the resultant thermosets were produced using vat photopolymerization 3D printing in the form of digital light processing (DLP) driven by thiol–ene or by free radical cross-linking, where green materials are a growing field of interest for more sustainable manufacturing. ,, While this instilled the resultant materials with a certain concentration of hydrolyzable linkages (because of the thiol selected), hydrolysis could be increased through the introduction of more labile linkages. Furthermore, the physical network properties could be more readily tuned through the introduction of other moieties.…”