Natural and Naturally Derived Photoinitiating Systems for Light-Based 3D Printing

Abstract

Photoinitiating systems (PIS) are key components in photocurable formulations (inks) for 3D printing. Natural PIS are promising and more environmentally friendly alternatives to conventional photoinitiators. These systems offer enhanced features such as less toxicity and therefore, higher biocompatibility. Furthermore, they can be found in a large "color palette” variety (absorbing in the different regions of the UV-visible spectrum) enabling new possibilities in the field of 3D printing. In this review, we outline the current efforts to implement natural and naturally derived PIS in light-based 3D printing. First, recently applied natural PIS and their performance for light-based 3D printing are discussed. In a second part, an overview of naturally derived PIS including the most common synthetic strategies are provided. Last, current challenges as well as future perspectives of the field are discussed.

Renewable Photopolymers: Transformation of Biomass Resources into Value-Added Products Under Light

“…β-Carotene can also act as a natural photosensitizer for both cationic and thiol–ene photopolymerizations . A variety of naturally present compounds were reported to serve as type II PIs to provide improved biocompatibility. , The solvents used in the processing of biomass to biosourced synthons, reactive diluents during photocuring, or reinforcing agents for better mechanical properties, , all can be replaced with biomass derivatives to accelerate the transition toward a greener community. The renewability of the final products should not be calculated solely on the eventual biomass content incorporated.…”

Crosslinked polymers based on monomers derived from renewable resources and their application potential

“…3D printing can be seen as an additional application field where these monomers could receive additional attraction [33][34][35][36][37][38]. Particular manufacture of prostheses for medical uses or dental restoration addresses interesting challenges [36,37].…”

“…Here, the new bio‐based dimethacrylate (Scheme 1) and a modified structure of the bio‐based dimethacrylate for example, as shown in Scheme 2, respectively, may become interesting alternatives to the currently used fluorinated polymers. 3D printing can be seen as an additional application field where these monomers could receive additional attraction [33–38]. Particular manufacture of prostheses for medical uses or dental restoration addresses interesting challenges [36, 37].…”

Light‐Mediated Polymerization Catalyzed by Carbon Nanomaterials

“…Light‐mediated polymerization has received increasing interest in polymer synthesis for use in diverse fields [1–19] . Examples include, but not limited to lithography, [4,9,20–22] printing based on 2D, [4,15,23,24] 3D [4,6,8,25–52] or 4D [27–29,53,54] patterning, holographic recording, [16,55,56] fabrication of prosthesis, [57] dental composites, [38,46,58] anti‐counterfeiting materials, [59] inks, [4,60,61] surface modification of solidified coatings [4,13,14,62–68] or adhesives [4,69–72] . Formulating of light‐sensitive compositions based on Chemistry 4.0, which was defined by the VCI in Germany as a combination of artificial intelligence (AI) and central data management, [73] can be seen as an additional challenging aspect [18] .…”