CA2.5 and PVOH were plasticized in a Leistritz ZSE 18HP-40D twin-screw extruder (L ¼ 40D) equipped with a liquid feeder for plasticizer addition. Polymers were dried overnight at 80 C in a ventilated oven before being introduced into polymer feeder. Screw speed was fixed at 250 rpm and the barrel temperature profile was set-up in function of the material to be processed. Extruded material was cooled down in awater bath (CA) or by air ejectors over a moving belt (PVOH) and pelletized downstream. Cellulose acetate was plasticized with 30 wt% triacetin and PVOH with 25 wt% glycerol. HEC plasticization was conducted in a different manner using a two-step process [9]. First, HEC was mixed with plasticizer and water in beakers at room temperature and left to swell overnight to form a premix. In a second step, the premix was melt-processed using a Brabender bench-scale kneader (model 50 EHT, 80 cm3 free volume) with cam blades at 110 C for 6 min. Plasticizer content was varied between 20 and 40 wt% and water was added at concentrations of 10 or 15 wt%.