Up-Cycling of LCD Glass by Additive Manufacturing of Porous Translucent Glass Scaffolds

Abstract

Additive manufacturing technologies, compared to conventional shaping methods, offer great opportunities in design versatility, for the manufacturing of highly porous ceramic components. However, the application to glass powders, later subjected to viscous flow sintering, involves significant challenges, especially in shape retention and in the achievement of a substantial degree of translucency in the final products. The present paper disclosed the potential of glass recovered from liquid crystal displays (LCD) for the manufacturing of highly porous scaffolds by direct ink writing and masked stereolithography of fine powders mixed with suitable organic additives, and sintered at 950 °C, for 1–1.5 h, in air. The specific glass, featuring a relatively high transition temperature (Tg~700 °C), allowed for the complete burn-out of organics before viscous flow sintering could take place; in addition, translucency was favored by the successful removal of porosity in the struts and by the resistance of the used glass to crystallization.

A review on the ceramic additive manufacturing technologies and availability of equipment and materials

“…Finally, ceramic additive manufacturing is expected to follow the general 3D printing concern with sustainability [371] and expand studies on its environmental implications (considering materials savings in the life cycle and energy consumption [372]). There are already related studies about the reusability/recycling of feedstock [354], the use of recycled glass as raw materials [373,374], and steel dust waste as an additive in ceramic 3D printing [375]. Also, care must be taken about the environmentally hazardous materials involved in 3D printing and post-processing [15].…”

Advanced Dye Sorbents from Combined Stereolithography 3D Printing and Alkali Activation of Pharmaceutical Glass Waste

“…Sintering may also be a fundamental step for products with a not-stochastic porosity [ 18 , 19 ], such as scaffolds fabricated by additive manufacturing technologies starting from glass slurries. Dasan et al [ 20 ] have recently discussed the manufacturing of three-dimensional translucent scaffolds, designed as supports for photocatalysts or parts of optical sensors (to detect noxious gases), by stereolithography as a reuse strategy for clear glass used in LCD displays.…”

“…In the case of LCD glass, the translucency of the sintered scaffold is based on a nearly full densification, with no concurrent devitrification, maximizing the optical quality of fired pieces. This in turn depends on the softening of glass at relatively high temperature, enabling the complete thermal degradation of organic binders before densification while avoiding the trapping of any pyrolytic residua [ 20 ]. A quite distinctive feature of pharmaceutical glass, explored in the present paper, is related to its sensitivity to alkali activation.…”

“…Components with a regular but tortuous structure, like the one offered by gyroids. (Cellular bodies defined by the packing of helicoidal channels, separated by curved membranes [ 20 ], effectively maximize the contact interface [ 28 ].) We will show that the contact interface can be enhanced by alkali activation of glass.…”

Desenvolvimento de suspensão fotossensível de vidro soda-cal-sílica para impressão 3D por processamento digital de luz (DLP)

“…Mais recentemente, uma pesquisa preliminar relatou a viabilidade de utilizar vidros de telas de cristal líquido (LCDs, da sigla em inglês) reciclados na produção de scaffolds translúcidos altamente porosos e com morfologia adequada a partir das técnicas de direct ink writing e processamento digital de luz [61]. Embora o DLP tenha proporcionado estruturas com geometrias mais complexas, igual à apresentada na Figura 12, ambas as metodologias permitiram obter scaffolds para aplicações em sensores ópticos para detecção de gases e como suportes de fotocatalisadores.…”