2.3. Preparation of thermoplastic starch/chitosan-based films by
blown film extrusion
The obtained resins were blown into films using a single-screw
extruder (LE-25-30/C; Labtech Engineering) – with an l/d ratio of
30, a screw diameter of 25 mm, and four controlled temperature
zones – connected to a film-blowing attachment (LF-400; Labtech
Engineering) with a ring-shaped die. The barreltemperature profile
was maintained at 130/140/140/140 ◦C (from feed inlet to die) and
the die temperature was set at 150 ◦C. Screw speed and nip roll
speed were adjusted to 35–45 rpm and 3 rpm, respectively.