Effects of chemical structure and molecular weight of plasticizer on physical properties of green tape in BaTiO3/PVB system

The effects of the chemical structure and molecular weight (Mw) of plasticizer on the physical properties of green tapes were investigated by measuring the rheological behavior of suspensions and estimating the tensile properties of green tapes. The BaTiO3 green tapes were fabricated from the suspensions prepared in nonaqueous media with poly(vinyl butyral) (PVB) and various plasticizers, such as di-octyl phthalate (DOP, Mw≈391), butyl benzyl phthalate (BBP, Mw≈312), and two kinds of polyethylene glycols (PEG400 (Mw≈400) and PEG1530 (Mw≈1300–1600)). As the suspension was prepared with lower Mw of plasticizer, the viscosity of suspension and flexibility of green tape was decreased and improved, respectively. The BaTiO3 suspension prepared with PEG1530 resulted in delamination of the cutting surface due to low flexibility of green tape. The chemical structure of plasticizer also affected the elongation behavior of green tape as a function of time. The BaTiO3 green tapes prepared with phthalate-based plasticizers having an aromatic unit (DOP and BBP) were found to be more stable for time-dependant elongation property of the green tapes than those prepared with glycol-based plasticizers having an aliphatic structure (PEG) in BaTiO3/PVB system.