Eventos Anais de eventos
COBEF 2023
12th Brazilian Congress on Manufacturing Engineering
Natural dispersants used in formulations for zirconia suspensions in additive manufacturing.
Submission Author:
Giovanna Rubo de Rezende , SP
Co-Authors:
Giovanna Rubo de Rezende, Carlos Fortulan
Presenter: Giovanna Rubo de Rezende
doi://10.26678/ABCM.COBEF2023.COF23-0331
Abstract
Zirconia is one of the main ceramic materials with attractive mechanical and electronic properties that has been applied in the manufacture of bodies by additive manufacturing (AM) where light curing in vat polimerization (VP) is highlighted. Suspensions with high solid loading and homogeneous dispersion are recommended to achieve the minimization of defects, low shrinkage and good mechanical properties. However, increasing the solid content of a material with a nanometer fraction increases the viscosity on an exponential scale, which is unfavorable for the maintenance of homogeneity and distribution in thin layers. In order to maintain the suspension’s rheological properties, dispersing agents and surfactants are added to prevent particle agglomeration and provide affinity with the light-curing resin, reducing the viscosity of the suspension. The use of vegetable oils as dispersants represents a strong appeal related to “green chemistry”, as they are renewable and non-toxic organic materials that can naturally contain surfactants, lubricants, plasticizers and solvents. Castor oil is already a consolidated product in cosmetics, plastic engineering, engine lubricants, among others, and as a surfactant in microbiology. In turn, cashew nut shell oil (LCC), due to its surfactant property, has been indicated as an ecological substitute for detergents and as additive in engine lubrication. In this research, the effect of these two natural dispersing agents on the photosensitive and rheological parameters of ceramic suspensions is being analyzed. Formulations containing zirconia powder (TZ-3Y-E) at 15% by volume, photosensitive resin (PEGDA 250 + phenylbis-phosphine oxide), solvent (n-methyl-2-pyrrolidone) at 10% by volume were developed using castor oil and LCC as dispersants at 3% by weight for viscosity tests, sedimentation test. The suspensions are being submitted to different times of light exposure. It is expected that the performance of natural dispersants will match that of the synthetic commercials, without ecological appeal, or will exceed it in terms of viscosity, settling and curing, without adversely altering the mechanical properties and surface finish of the final parts. In the fulfillment of these expectations, the studied dispersants may be suggested as an accessible, economically viable and scientifically reliable alternative for the production of ceramic bodies by AM.
Keywords
Additive manufacturing, Zirconia, Dispersants
