Abstract: Glycerol was used as a plasticizer to prepare zein-PPC films from zein and polypropylene carbonate (PPC) by extrusion. The mechanical characteristics, morphology and structure of zein-PPC films were studied. The tensile strength of zein-PPC films was enhanced by adding PPC and reached maximum level (30.11 MPa) at a PPC content of 30%. A Halsey model reflecting the relationship the tensile strength of zein-PPC films and relative humidity was established. The composite films had stable thermal properties as demonstrated by differential scanning calorimetry (DSC) analysis. FT-IR and X-ray analyses indicated the formation of ester bonds from carboxyl groups in zein and hydroxyl groups in PPC, maintaining the stability of zein-PPC films.

Key words: zein, polypropylene carbonate (PPC), film, mechanical characteristics, scanning electron microscopy (SEM)