Water uptake of bioplastics was determined following the ASTMD570 norm (ASTM D570-98, Standard test Method for Water Absorption of Plastics) (American Society for Testing Materials,2005) using at least three 50 mm × 10 mm × 3 mm specimens. Ini-tially, specimens were put into an oven at 50 ± 2◦C for 24 h in order to determine their dry weights (w0). After that, specimenswere immersed in distillate water for 2 and 24 h at room tempera-ture. Finally, each specimen was periodically weighed (wt) or driedunder the same conditions before weighing again (wf). According tothis method, water uptake and loss of soluble mater were calculatedas follows:
Water update (wt%)