Glass powders and reactive silicone binder: Application to digital light processing of bioactive glass-ceramic scaffolds

Powdered \u2018silica-defective glasses\u2019, mixed with silicones, have been already shown as a promising solution for the sintering, in air, of glass-ceramics with complex geometries. A fundamental advantage of the approach is the fact silicones act as binders up to the firing temperature, at which they transform into silica. A specified \u2018target\u2019 glass-ceramic formulation is achieved through the interaction between glass powders and the binder-derived silica. The present paper is dedicated to the extension of the approach to the digital light processing of reticulated glass-ceramic scaffolds, for tissue engineering applications, starting from glass powders suspended in an engineered photocurable silicone-based binder. The silicone component, besides providing an extended binding action up to the maximum firing temperature, stabilizes the 3D-printed shapes during sintering. The formation of a rigid silica skeleton, from the transformation of the silicone binder, prevents from excessive viscous flow of softened glass. The final phase assemblage does not depend simply on glass devitrification but also on the glass/silica skeleton interaction

Glass powders and reactive silicone binder: Interactions and application to additive manufacturing of bioactive glass-ceramic scaffolds

A novel concept for the additive manufacturing of three-dimensional glass-ceramic scaffolds, to be used for tissue engineering applications, was based on fine glass powders mixed with a reactive binder, in the form of a commercial silicone. The powders consisted of ‘silica-defective glass’ specifically designed to react, upon firing in air, with the amorphous silica yielded by the binder. By silica incorporation, the glass was intended to reach the composition of an already known CaO[sbnd]Na 2 O[sbnd]B 2 O 3 [sbnd]SiO 2 system. Silica from the binder provided up to 15 wt% of the total silica. With the same overall formulation, silicone-glass powder mixtures led to nearly the same phase assemblage formed by the reference system, crystallizing into wollastonite (CaSiO 3 ) and Ca-borate (CaB 2 O 4 ). Samples from silicone-glass powder mixtures exhibited an excellent shape retention after firing, which was later exploited in highly porous reticulated scaffolds, obtained by means of direct ink writing (DIW).Fil: Elsayed, Hamada. Università di Padova; Italia. National Research Centre; EgiptoFil: Picicco, Martiniano. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; ArgentinaFil: Dasan, Arish. Alexander Dubček University of Trenčín; EslovaquiaFil: Kraxner, Jozef. Alexander Dubček University of Trenčín; EslovaquiaFil: Galusek, Dušan. Alexander Dubček University of Trenčín; EslovaquiaFil: Bernardo, Enrico. Università di Padova; Itali

Insights on numerical models to predict potential recyclability of spent refractories from steel making industry

The present study is part of the CESAREF (Concerted European action on Sustainable Applications of REFractories) doctoral network, started in late 2022. The aim of the consortium is the contribution to scientific breakthroughs inherent to refractories for steel making sector thanks to transversal competences deriving from academic and industrial realities. European green deal and circular economy targets set by EU for 2025 are also related to the massive consumption of refractory materials in the steel industry. Operative lifetimes of refractories range from hours to several months depending on their role. As a result of increasingly tightened policies and disposal costs, and due to recent supply chain shortages, end-of-life refractories recovery and recycling practices are receiving great attention. Some of the core requirements for sustainability and circularity are the reduction of open-loop and down scaling strategies, to maintain refractory materials value as long as possible, of the end-of-life materials. Over the years application of numerical models has proved to be a useful strategy for researchers facing in-use issues related to refractory materials. In this study, different finite element models (FEM) applied to end-use refractories are discussed to understand their suitability for potential recyclability prediction. Thermomechanical characterization of prior- and post-use materials allow to identify the critical issues related to numerical models' development. The comparison between empirical results and the appropriate numerical model allow us to identify suitable pathways to improve refractories sustainability

Reuse and recyclability of refractories from steel industry

Part of the CESAREF consortium, the study presented here is dedicated to the characterization of refractory material properties after usage for potential reuse and recyclability determination. The aim of this doctoral study is to provide an insight on the variation of specific materials’ key properties (such as thermal conductivity, thermal expansion, Young’s module, modulus of rupture) after operations. Mesoscale aging studies may allow to define appropriate Finite Element Models ( to foreseen operative conditions of the refractory. Furthermore, application of an adapted FMECA (Failure Modes, Effects, and Criticality Analysis) fatigue integrated approach can be a further reliable tool to better predict refractories’ lifetime. Also, MCDA (Multi Criteria Decision Approach) implementation could help in detecting the necessary strategies to define the most convenient recycling routes

Talc, Spodumene and Calcium Carbonate Effect as Secondary Fluxes in Triaxial Ceramic Properties

Triaxial ceramics (clay-quartz-feldspar) represents a significant proportion of traditional ceramic production; art, craft and/or industrial. The use of flux is widely used in order to modify the range of maturation of ceramic pastes. The objective of the present study is to establish the influence of the addition of different secondary fluxes in the plasticity, sinterability, porosity, contraction, and mechanical properties of triaxial ceramics produced in a wide range of temperatures (800º-1200ºC). The samples were elaborated with national raw materials with industrial quality and availability. A traditional clay-quartz-feldspar mixture was employed as a standard; In the present study Talc, Spodumene, and Calcium carbonate were chosen as secondary fluxes and partially replace the feldspar. All the fluxes enhanced the sinterization, Furthermore the use of talc permitted to obtain a complete dense ceramic at 1200ºC. On the other hand the use of spodumene resulted in materials with high elastic modulus.Centro de Tecnología de Recursos Minerales y CerámicaFacultad de Ciencias Exacta

Informe de personal de apoyo: Picicco, Martiniano (2012-2013)

Proyectos de investigación en los cuales colabora: • “Agentes de sostén cerámicos para Shale y Tight (Gas & Oil)”. Convenio YPF – CIC – CONICET (12/3/12 – 13/3/13) • “Procesamiento, propiedades y comportamiento de materiales cerámicos tradicionales” Sub-línea de investigación a cargo del Investigador CIC Dr. Nicolás M. Rendtorff

Informe de personal de apoyo: Picicco, Martiniano (2014-2015)

Proyectos de investigación en los cuales colabora: a) “Agentes de sostén cerámicos para Shale y Tight (Gas & Oil) FASE 3”. Convenio YPF – CIC – CONICE

Informe de personal de apoyo: Picicco, Martiniano (2011-2012)

Proyectos de investigación en los cuales colabora: a) Control y mantenimiento de hornos y muflas del CETMIC b) A cargo del ensayo de Cono Pirométrico Equivalente c) Colaboración con investigadores CIC/CONICET del CETMI

Novel bioceramics from digital light processing of calcite/acrylate blends and low temperature pyrolysis

Porous bioceramic composites with complex shapes were easily fabricated starting from fine calcite (CaCO3) particles (<10 \u3bcm) immersed in a liquid photocurable polymer. The building of 3D structures, layer-by-layer, was achieved by means of Digital Light Processing (DLP), using a commercial stereo-lithography 3D printer. The pyrolysis of the hardened photosensitive polymer, in nitrogen atmosphere (at 500 \ub0C), left calcite powders embedded in an amorphous carbon matrix, without any degradation of the main phase, which retained its biocompatibility, according to the cell culture studies. In addition, calcite was successfully converted into hydroxyapatite (HAp), by simple immersion of samples in a phosphatizing bath (aqueous solution of sodium phosphate), for 2 weeks, obtaining HAp-pyrolytic carbon composite scaffolds. The developed structures, after phosphatization, exhibited an adequate strength-to-density ratio (compressive strength of 1.4 MPa with porosity of about 80 vol%

Glass powders and reactive silicone binder: Application to digital light processing of bioactive glass-ceramic scaffolds

Powdered ‘silica-defective glasses’, mixed with silicones, have been already shown as a promising solution for the sintering, in air, of glass-ceramics with complex geometries. A fundamental advantage of the approach is the fact silicones act as binders up to the firing temperature, at which they transform into silica. A specified ‘target’ glass-ceramic formulation is achieved through the interaction between glass powders and the binder-derived silica. The present paper is dedicated to the extension of the approach to the digital light processing of reticulated glass-ceramic scaffolds, for tissue engineering applications, starting from glass powders suspended in an engineered photocurable silicone-based binder. The silicone component, besides providing an extended binding action up to the maximum firing temperature, stabilizes the 3D-printed shapes during sintering. The formation of a rigid silica skeleton, from the transformation of the silicone binder, prevents from excessive viscous flow of softened glass. The final phase assemblage does not depend simply on glass devitrification but also on the glass/silica skeleton interaction