Ceramic Stereolithography of Bioactive Glasses: Influence of Resin Composition on Curing Behavior and Green Body Properties

Abstract

Herein we report on the preparation of a bioactive glass (BAG)-based photocurable resin for the additive manufacturing of BAG scaffolds with high filler loadings. The preparation of glass/ceramics resins for stereolithography with high filler loading is always a challenge, especially for fillers with a high refractive index variance. Various photocurable resin compositions with and without bioactive glass fillers have been investigated to see the influence of bioactive glass on physical properties of the resin and resulting green body. The effect of concentration of monomers, reactive diluent, light absorber (Sudan orange G dye), photoinitiator (PI), non-reactive diluent, and fillers (BAG) on rheology and photocuring behavior of the resin and tomography of the resulting 3D structures have been investigated. The BAG contents affect the rheology of resin and influence the rate of the polymerization reaction. The resin compositions with 55–60% BAG, 10% PEG-200 (diluent), 1% of PI and 0.015% of the dye were found to be suitable compositions for the stereolithographic fabrication. A higher percentage of PI caused over-curing, while a higher amount of dye decreased the cure depth of the resin. The micro-computed tomography (µ-CT) and scanning electron microscopic (SEM) images of the resulting green bodies display a relatively dense glass scaffold without any visible cracks and good interlayer connection and surface finishing. These properties play an important role in the mechanical behavior of 3D scaffolds. This study will be helpful to prepare high density glass/ceramic slurries and optimize their printing properties.

Infrared irradiation to drive phosphate condensation as a route to direct additive manufacturing of oxide ceramics

“…8 The exposure time to light is in the range of 1000 ms to a few seconds. 7,8,42,43 The build time scale for each layer is typically 10−60 s because each layer requires application of fresh liquid in a recoat step. 8 Concerning particle size, ceramic powders from 0.2 to 12 μm are usually used in resins for CSL.…”

“…8 Concerning particle size, ceramic powders from 0.2 to 12 μm are usually used in resins for CSL. 7,8,42,43 The resin viscosity should be relatively low to facilitate the recoating and self-levelling of the resin. Moreover, to reduce scattering and lower the polymerization time, a decrease in the powder size and a close matching between the resin and powder refractive indexes are desirable.…”

“…However, obtaining pure ceramic parts requires that these printed bodies be subjected to appropriate thermal treatments that first remove the organic phase (debinding) and then densify (sinter) the part to achieve acceptable mechanical properties. 7,8 Another approach may be to combine photonic heating technologies, which can be delivered quickly and remotely with standard AM process flows, with inorganic binders that can be directly converted into intergranular ceramic phases that bind the ceramic part together. When converted into monolithic parts, these binders are sometimes known as "chemically bonded ceramics," rather than "sintered ceramics."…”

Novel Additive Manufacturing Materials for Waste Heat Deduction

“…[ 22–24 ] Especially fractions above a certain threshold can increase the properties dramatically, but some processing properties, like the viscosity, are mostly affected negatively so that only a certain limit can be reached. [ 25–27 ]…”

“…[22][23][24] Especially fractions above a certain threshold can increase the properties dramatically, but some processing properties, like the viscosity, are mostly affected negatively so that only a certain limit can be reached. [25][26][27] The three approaches in this work differ strongly regarding material composition and overall properties and each system has been separately optimized to reach the best balance between thermal performance and AM applicability.…”