A Simple and Efficient Model to Determine the Photonic Parameters of a Photopolymerizable Resin Usable in 3D Printing

Abstract

This study provides insight into the relationship between the photochemical reactivity and the photonic parameters of an acrylate formulation usable in digital light processing (DLP) 3D printing. First the photoreactivity of riboflavin tetrabutyrate (RFT) used as a non‐toxic photoinitiator is assessed by laser flash photolysis in the absence and in the presence of an amine as co‐initiator. RFT alone is able to photopolymerize the acrylate formulation at a rate which is drastically increased when the co‐initiator is added. Then, the depth of light penetration (Dp) and the critical energy (Ec) to form a polymer film were measured and compared to those determined from the Bouguer‐Lambert‐Beer law for Dp and from the Stockmayer equation and photopolymerization experiments for Ec. A new proposed model is able to predict the in‐depth acrylate conversion within a printed part with a relatively low input of experimental parameters. Confocal Raman microscopy is used to discuss the effect of the photobleaching of RFT in the absence of co‐initiator on the photopolymerized films. Finally, it is shown that this formulation performs quite well for 3D printing with a resolution close to the best performance of the DLP printer.

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

“…18 In the triplet state, RF can generate radical ions through triplettriplet annihilation or undergo self-quenching. 29 Thus, RF can be used as a photosensitizer as well as a reducing agent due to the ribityl moiety. 22,23 However, this mechanism is not very efficient and very often co-initiators such as amines are employed as external hydrogen donors.…”

“…B) RFT-based 3D-printed model version of the "Notre Dame de Paris" showing high-resolution details. 29 Reprinted with permission from Ref. 29.…”

“…Aiming for these properties, Champion et al could success-fully perform DLP 3D printing of a biobased acrylate formulations in the presence of RFT and an amine co-initiator. 29 The 3D-printed structures show enhanced resolution and level of detail (Figure 3B). This work is the first employing RF-derived PIS in other than hydrogel 3D printing.…”

“…Published by American Chemical Society. B) RFT-based 3D printed model version of the "Notre Dame de Paris" showing high resolution details 29. Reproduced with permission.…”

3D printed objects obtained by combination of radical photopolymerization and photo sol–gel reaction: towards reinforced thermomechanical properties

“…Moreover, acrylate photopolymerization leads to thermoset polymers with structural inhomogeneities. 4,5 Combination of radical and cationic photopolymerization [6][7][8] is an interesting alternative to overcome these limitations. Besides compensating the shrinkage by volumetric expansion due to the ring-opening polymerization of (spiro/)epoxy compounds, [9][10][11] the living character 12 of this reaction improves interlayer adhesion.…”