Recycling industrial waste polymer as a binder system for ceramic injection molding feedstock

Abstract

Ceramic injection molding is a widely used manufacturing process for producing high-precision ceramic components. However, the high cost of traditional binder systems, as well as non-ecological aspects of these binders, may limit its broader applications. This study investigates the potential use of polyvinyl butyral industrial waste containing plasticizer as a sustainable alternative binder system for ceramic injection molding, utilizing alumina powder with a mean particle size of 0.7 μm. The mixing behavior of the binder-powder mixture was evaluated through torque measurements, identifying a critical solid loading point at 56 vol%. The rheological properties of the feedstocks were characterized, revealing that their viscosity remained below the recommended threshold of 1000 Pa s, suitable for ceramic injection molding. The activation energy, ranging from 18 kJ/mol to 45 kJ/mol, demonstrated favorable temperature sensitivity for the process. Subsequently, the feedstocks were successfully injection molded into test specimens, followed by the debinding and sintering processes to achieve the final density. Mechanical testing of the sintered ceramic parts indicated performance comparable to parts produced with traditional binder systems, with final densities exceeding 4 g/cm³, a bending modulus of approximately 15000 N/mm2, and bending strength up to 139 N/mm2. These findings suggest that incorporating industrial waste polymer as a binder system is a cost-effective, environmentally friendly alternative that maintains the quality of molded ceramic parts. © 2024 The Authors