Visible Light Photoinitiator for 3D-Printing of Tough Methacrylate Resins

Abstract

Lithography-based additive manufacturing was introduced in the 1980s, and is still the method of choice for printing accurate plastic parts with high surface quality. Recent progress in this field has made tough photopolymer resins and cheap LED light engines available. This study presents the influence of photoinitiator selection and post-processing on the thermomechanical properties of various tough photopolymers. The influence of three photoinitiators (Ivocerin, BAPO, and TPO-L) on the double-bond conversion and mechanical properties was investigated by mid infrared spectroscopy, dynamic mechanical analysis and tensile tests. It was found that 1.18 wt % TPO-L would provide the best overall results in terms of double-bond conversion and mechanical properties. A correlation between double-bond conversion, yield strength, and glass transition temperature was found. Elongation at break remained high after post-curing at about 80–100%, and was not influenced by higher photoinitiator concentration. Finally, functional parts with 41 MPa tensile strength, 82% elongation at break, and 112 °C glass transition temperature were printed on a 405 nm DLP (digital light processing) printer.

Development of keratin-based membranes for potential use in skin repair

“…The equation could be further optimized by including parameters such as the optical properties, homogeneity of the material, the penetration and attenuation of UV light through the keratin resin, and the UV absorption by the constituent molecules of the resin. Other publications have detailed on the effect of various complex parameters in light-based crosslinking, particularly for 3D printing purposes, including the critical energy required to initiate polymerization, the penetration depth of the curing light [59,60], and UV absorption [61]. These reports focused on one or two variables and involved synthetic materials that have been extensively characterized.…”

Concurrent Modelling and Experimental Investigation of Material Properties and Geometries Produced by Projection Microstereolithography

“…A successful PµSLA system, in general, requires an optimized resin formulation. The current available photosensitive resins consist of a single or a mixture of monomers and oligomers, photoinitiator, photoblocker, and enhancing additives [10,[17][18][19]. The concentration of each component influences the process parameter values selected to achieve the desired material properties and geometrical accuracy [20].…”

Additive Manufacturing of Personalized Pharmaceutical Dosage Forms via Stereolithography

“…Although the loading of 1.00% may seem high there are a number of publications in the literature utilizing higher concentrations. In a publication by Steyrer and researchers [61], they illustrated the possibility of using a concentration loading of 1.18 wt% of Omnirad TPO-L (Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate) in the fabrication of 3D printed part on a 405 nm Digital Light Processing (DLP) printer, and although it may not be the same process used in this study it does, however, rely on a similar technology using UV light to cure the photopolymer. In addition to this, a concentration in excess of what is proposed in this study was utilized by Asikainen et al [62] in which they assessed lidocaine drug release from photo-crosslinkable PCL scaffolds fabricated by SLA technology.…”