The films were processed in a pilot single screw extruder (BGM,
model EL-25, Brazil) equipped with a screw diameter (D) of 25mm
and a screw length of 28 D, four heating zones, and die with two
3 mm diameter holes for the production of pellets. For the production
of tubular films, the same extruder was used, with five heating
zones, 50 mm film-blowing die with internal air for the formation
of the film ‘‘bubble’’