Abstract:

The polypropylene carbonate-soy protein isolate (PPC/SPI) composite film was prepared by extrusion using
glycerol as a plasticizer. The mechanical properties, opacity, and water resistance (water absorption and water-soluble) of
the composite film were studied as a function of PPC/SPI ratio (m/m), and the thermal properties and structure were also
examined. The study indicated that with increasing PPC/SPI ratio (from 1.0:1, 1.5:1, 2.0:1, 2.5:1 to 3.0:1), the flexibility and
opacity of the composite film were increased, water absorption gradually became lower, mass loss was significantly reduced.
Moreover, the PPC/SPI composite film exhibited good thermal stability and its structure was dense, uniform and stable.

Key words: soy protein isolate, poly (propylene carbonate), composite film, mechanical properties, differential scanning calorimetry (DSC)