Spreading and drying of starch‑glycerol‑fiber film produced by tape‑casting

Abstract

The objective of this work was to evaluate spreading and drying processes of starch‑glycerol‑cellulose fiber film prepared by tape‑casting. Suspension spreading was evaluated at 50, 150 and 250 cm min^‑1, followed by drying in a forced‑air oven at 40 or at 70ºC; suspension spreading was also evaluated at 150 cm min^‑1, followed by film drying on the tape‑casting support at 22ºC and 60% relative humidity, at air‑drying velocity of 4, 6, and 8 m s^‑1 in the drying tunnel. Rheological tests showed that suspension spreading at temperatures below 50°C had the modulus of elasticity superior to the modulus of viscosity, in all oscillation frequency spectrum. Micrographs showed films dried at 40 and 70ºC without defects and whose mechanical properties showed no differences. Spreading speed and air‑drying velocities did not change the drying time and film properties. The drying time can be reduced to approximately two hours, which is important to the scale‑up of film production.