Polymer Effects on the Chemorheological and Drying Behavior of Alumina-Poly(vinyl alcohol) Gelcasting Suspensions

摘要: A new gelcasting system based on aqueous alumina (Al2O3)–poly(vinyl alcohol) (PVA) suspensions cross-linked via titanium ion complexation has been developed as a feedstock for bulk casting and solid freeform fabrication (SFF) routes. Its chemorheological properties, measured by stress viscometry oscillatory techniques, exhibited strong dependence upon polymer hydrolysis molecular weight. The gelation time of systems constant PVA volume fraction (φPVAsoln) cross-linker concentration decreased with increasing degree weight, whereas their steady-state elastic modulus (G′) the opposite dependence. Stress evolution during drying gelcast layers was in situ using controlled-environment, cantilever deflection apparatus. Both maximum residual stresses increased hydrolysis, only modest weight effect observed.