Fast Hydrolytically Degradable 3D Printed Object Based on Aliphatic Polycarbonate Thiol‐Yne Photoresins

Abstract

Like the thiol‐ene addition reaction, the thiol‐yne addition reaction can be initiated thermally and photochemically. The latter route therefore can be utilized for vat photopolymerization‐based additive manufacturing (AM). In this work, the following is reported (1) the synthesis of an aliphatic polycarbonate oligomer with a pendant alkyne functional group as a hydrolytically degradable “yne” component; (2) a new thiol‐yne photoresin formulation that has been applied in digital light processing (DLP) 405nm 3D printing to print objects with high resolution (50 µm layer thickness); and (3) the successful demonstration of fast hydrolytic degradation of a 3D printed object in aqueous alkaline solution. Therefore, the incorporation of an aliphatic polycarbonate alkyne component and ester thiols in the photoresin formulation is effective for imparting the ability to do fast hydrolytic degradation of 3D printed objects.

Hydrolytically Degradable Poly(β‐amino ester) Resins with Tunable Degradation for 3D Printing by Projection Micro‐Stereolithography

“…The resin chemistries used currently in PμSL based degradable 3D printed parts include poly(propylene fumarates) and copolymers thereof, biobased polyesters, and thiol‐yne chemistry. [ 15,29–32 ] Although promising, these resin chemistries have limited tunability over degradation rate and behavior. Moreover, the synthesis of these multifunctional macromers that form degradable networks commonly involves multiple functionalization and purification steps, which makes the development of large numbers of polymers with diverse properties difficult.…”

3D Printing of Thiol‐Yne Photoresins through Visible Light Photoredox Catalysis

“…Recently, our group reported hydrolytically fast degradable thiol-yne photoresin containing the aliphatic polycarbonate for DLP 3D printing (λ max = 405 nm). [11] While most works used 405 nm as light source in 3D printing, Griesser's group was the first to utilize visible light (λ max = 465 nm) in DLP 3D printing of thiol-yne resin. [12] In his research, the visible light thiol-yne polymerizations are activated via a photoinitiation mechanism by photoinitiator Ivocerin, which is a commercial germanium-based photoinitiator developed by Ivoclar Vivadent Inc. [13] As a class, photoredox catalysts (PRC) have the remarkable property of having members with strong oxidizing or reducing properties to catalyse the thiol-yne addition.…”

“…[18,19] Furthermore, the amount of photocatalysts to be added in photoresins potentially could be catalytic amount compared to that of the photoinitiators (typically ∼ 0.2-2 % in the formulation). [11,20] Transition metal complexes such as Ru(bpz) 3 (PF 6 ) 2 and fac-Ir(ppy) 3 were evaluated for the thiol-ene and thiol-yne coupling. [15,[21][22][23][24] The application of transition metal catalysts improved the selectivity in favour of CÀ S bond formation.…”

“…This development allows the possibility of surface functionalization of 3D printed objects. Recently, our group reported hydrolytically fast degradable thiol‐yne photoresin containing the aliphatic polycarbonate for DLP 3D printing ( λ max =405 nm) [11] . While most works used 405 nm as light source in 3D printing, Griesser's group was the first to utilize visible light ( λ max =465 nm) in DLP 3D printing of thiol‐yne resin [12] .…”

A novel strategy for producing high‐performance continuous regenerated fibers with wool‐like structure

“…Then, the extracted cortical cells are well mixed with the purified linear keratin to prepare the solution (Figure 1C) for wet spinning, while the keratin is yielded in advance by dissolving wool waste in terms of the abovementioned DTT/SDS system (Figure 1C). For purposes of improving toughness of the regenerated keratin fibers, a few flexible poly(ethylene glycol) diacrylate (PEGDA) are incorporated as toughening agent, whose vinyl groups can react with sulfhydryl groups of the decrosslinked keratin using 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU) as catalyst [38][39][40][41] playing the role of precrosslinking (Figure 1D) and increasing intermolecular interactions. Last, the asspun regenerated keratin fibers, in which the cortical cells serve as the reinforcement and the linear keratin as the binder, are further crosslinked for strengthening to meet the application requirements for mechanical properties.…”