Production and Properties of Spin-Coated Cassava-Starch-Glycerol-Beeswax Films

Cassava-starch based polymer films containing glycerol as a plasticizer (1.0-2.5-5.0%, w/w) and different lipids as additives (paraffin, stearyl alcohol, and beeswax -0.25-0.5-1.0%, w/w) were produced. Control films were produced by heating a mixture of glycerol, starch, and water, while treated films were produced by the addition of lipids/ethanol solutions. The solutions were kept at around 70 degrees C during amalgamation, and once congealed, were placed in a vacuum oven for 1 h at 90 degrees C. The solutions were then spun on 7-inch diameter non-stick disks, allowed to dry, and conditioned at 23 degrees C and 50% RH before testing. Cassava starch-glycerol-beeswax films were successfully produced with a stable film structure at glycerol concentration equal or below 5% (w/w). Addition of glycerol and beeswax did not visually change the color of the films. Increasing glycerol content improved elongation while decreasing tensile strength. Increasing the glycerol concentration from 1.0 to 5.0% increased the water vapor permeability by 150% and addition of beeswax further increased these values by 250%.