AbstractResponse surface methodology was used to analyze the effect of glycerol (X1) and ethylene–acrylic acid (EAA) level (X2) on the objective (water solubility index (WSI), water absorption index (WAI), and tensile strength) attributes of a poly(vinyl alcohol) (PVOH)/starch‐blended plastic resin. A rotable central composite design was used to develop models for the objective responses. The experiments were run with different barrel temperatures, such as zone 1: 100°C, zone 2: 100°C, zone 3: 105°C, and zone 4: 105°C, respectively, with a feed rate of 20 g/min and screw speed of 25 rpm. Responses were most affected by changes in glycerol level (X1) and to a lesser extent by EAA level (X2). Individual contour plots of the different responses were overlaid, and regions meeting the optimum WSI of 6.10%, WAI of 5.57 g gel/g dry wt, and tensile strength of 62.14 MPa were identified at the glycerol level of 72.41 mL and the EAA level of 36.03 g, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009